Capacitor Mods 101

[charlie]

Ok,
So I'm CERTAINLY no EE, lol.
But I've heard that some mobo's may benefit from additional capacitor volume or number on a motherboard.
So, I guess the idea is to increase "capacitance" or the amount of "stored energy" available to the circuit, right??
So, if you have 6.3v 2200uF capacitors, I know you can ADD an identical Capacitor in paralell to the first one...

But how about replacing the cap in whole?
Just remove the 6.3v/2200UF and replace with a 6.3v/3700uF or how about a 6.3v/10000uF.........
Can you just solder a new one in place and flip the board on? Or is there some process of having to pre-charge the new caps????????

How to select the best replacement caps?

C

[Maelstrom2160]

alot of caps are chosen for their resonant frequency, as in the frequency when the caps impedance drops to non exsistant, basicly its a filter cap for lowering interference outa the band in use. Those large digital PSU electrolytics tend to be selected for that, they dont need to really be anything close to that 1000-3300uF value

ya dont wanna be changing much TBH adding caps in parallel to other power caps could lead you into creating ringy resonant circuits, cause of resonant harmoic modes or some crap ;()

paralleling caps onto the larger PSU caps on the board will lower the ESR of what would have been the single caps ESR, alowing the caps to discharge at a faster rate.

But u'll also lower the impedance of ya PSU lowering the noise on their lines and increasing the various IC's ability to focus on its job instead of waisting time screwing with interference

purer powers a good thing!

if anything it'll help with stability at high OC's unless the onboard powers a POS, not much else i dont think, im rookie though dont take my word for it

change the electrolytics for low ESR OS-con's or any other decent cap would probably be best, dont parralel em, improvments would be extreamly little though

or ya could parallel the larger PSU electrolytic on the stage ya screwing with, with a MLCC that resonates at the mid point of the band that stage works at

dunno if it'd be any good, dependant curcuit ect

im a rookie, for all i know im talkin complete &^$^

[enzoR]

you can add the exact same type of cap (from the same/dead mobo) to the backside of your mobo in parallel. that is the best way, only do that to the filtering caps (the biggest ones)

[cetoole]

Is it possible to replace the caps with Black Gates and set it up in the Super E configuration? I don't even know if Black Gates would fit on my board.

[blinky]

*PAGING LASTVIKING TO THREAD 47991*

LV knows a lot about cap mods, from what i gather from his, u should use the same capacitance or higher than what is on the mobo, and a higher voltage rating. also make sure to use low-ESR caps, dunno what that means but it seems important

[LorD_Kvadd]

So technically I could take all the caps from my dead nf7-s and solder them to the backside of my other nf7-s? Putting them into a parallell circuit then. Hrm maybe something I should try.

[charlie]

we need someone to give a lecture about what a capacitor does. We've heard they filter voltage, that's nice. They "store" power, of course....but they don't MAKE the power, that comes from the mosfets, right?
in particular, my DFI 855gme has some weak looking 6.3v/2200uF caps (only 3 of em) around the cpu socket. This board is made for the "green" DOTHAN, but of course, I'm doing bad, bad things to it and am pushing it WAAAAYYYY beyond it's intended spec's.

C

[Hell-Fire]

Until I get back from out of town, and finishing up my modding for members here, I cant spend much time on the subject....so hopefully someone will get to this.

But heres a very general idea.

You are right charlie, the power in a circuit (whether that be core, vdimm, etc) comes from regulators not from the capacitors. There are many things in a circuit loop that affect the current/voltage and how it is applied to its target. The capacitor is there to "filter" out leaking current among other things. They are truly there in an effort to oppose any sudden changes in potential (voltage spikes) which as we all know is very bad for stability. Heres a good test to see how effective your capacitors are. Either get one from a dead board, or remove one from yours for this experiment. Be sure to pick a capacitor that you can adequately supply voltage to...meaning, if you have a 16v capacitor, you better be able to supply it with atleast 16.5v so we can do the experiment. You should construct a simple circuit with a power supply, resistor, and capacitor. A resitor above 2500ohms is a good choice. You need to have either jumpers or switches that allow you to disconnect the capacitor from the power supply AND resistor once it is fully charged. Charge the capacitor until it stops charging and then remove it from the loop.....be sure that when you setup your loop that when you remove the capacitor that its ends are free and not shorted together. Continue to measure the voltage across the capacitor. If it drops quickly you know your caps arent to good...meaning its leaky, which is why they prob use many of them for single loops.

When we start adding capacitors in parallel to an existing circuit, we are effectively doubling the capacitance (ability to withstand spikes) as well as helping with any current leakage across the stock capacitor. Basically when the current hits the 2 caps that are in parallel, the current gets split between the 2 of them and then emerges on the other side as the same current value as when it entered. The fact that we have split the current reduces "the strain" on a single capacitor and reduces/limits any leakage that may be occuring. The thing is this....a capacitor has a max voltage rating with any given capacitance. This allows us to determine the max charge it can store. This is why we see capacitors with something large like a 16v rating for our circuit paths carrying the 12v rails. Reason being this; if a capacitor hits its max voltage rating it will cease to let any further current flow between its terminals and it will either begin to discharge (not likely on motherboards) or most likely simply sit there and not let anything on its oppsing side stay powered on.

Alot of people get confused when looking at a capactor that says 6.3v on it, but is only reading 3.65v..etc etc. You always have to use a capacitor with higher rarings for these types of applications. This also yields the fact that as we get closer and closer to its max rating, the leakage can become a real problem...yet another reason to have either high quality capacitors, or run them in parallel.

It is ok to change out capacitors for ones with higher capacitance, since thats what we are doing anyway when adding them in parallel when modding, but I highly reocmmend keeping the voltage rating the same. And no since swapping out a capacitor with a higher capacitance if the one you are swapping it with is just as generic..better to just go parallel.

One of the most important components for motherboards circuit loops that have capacitors in them is the inductor (chokes). They are truly the things that are "filtering" out any AC signal that our trusty power supplies let sliip through. The more AC current a capacitor gets hit with, the harder time it has with leakage. Adding a choke in parallel to the onboard ones where the 12v aux hits the motherboard is generally a good thing to do as the small ones they typically use are not effective enough imho. Reason again why a good quality power supply is such an important component when it comes to overclocking since if it lets to much AC through, the motherboard can really struggle.

[charlie]

Hell-Fire....great notes :D
Now what to do if you have a situation where the board is designed for a CPU with certain specs and you want to like double the default POWER applied? I always thought a cap was kinda like a "reserve" of power...so that a big charged capacitor could supply extra power in times of need even though the power regulation can't meet the need??
Like a CAP in a car stereo system... The car battery system can't supply the freeking 75A of power when the 1000W monoblock AMP hits a hard 30hZ bass note, so the Cap supplies the "overload" or needed power, right?
So if a board has a sub-par power supply/reg circuit, will larger capacitors help?? Because adding mosfet becomes NEAR impossible unless yer some freekin wizard who makes his own power reg breadboards and hooks them up to the motherboard.

[charlie]

So when shopping capacitors we have to note the physical size. The typical Nichicon/Rubycon 6.3v/2200uF is 10 x 25mm......
There's only space on the PCB for a 10mm diameter piece (when the caps are close together) and www.mouser.com shows no high uF caps at 10mm diam.
You can get 6.3v/3900uF aluminum Nichicon caps that are 12.5mm x 25mm for example.

[Hell-Fire]

Thanks charlie.

Yes, a capacitor is pretty much a "reserve" of power. It charges as it accepts current..up to the point where max rating is met. Then it will either hold that voltage across it or discharge.

A capacitor indeed stores charge between its terminal, which is passed to the rest of the loop. I certainly dont know the inner workings on how the car audio amps are working, but you are right to think of caps as components used to store charge and then provide charge when needed. The rate at which they discharge depends on the resistance of the circuit they are a part of.

Yes, on boards with terrible voltage regulation, due to the controllers only, then larger caps will certainly be beneficial. They will hold more charge across them and for longer periods of time...but I still recommend 2 caps in parallel opposed to one large cap...unless you can use very very high quality caps with close to zero current leakage.

[Hell-Fire]

So when shopping capacitors we have to note the physical size. The typical Nichicon/Rubycon 6.3v/2200uF is 10 x 25mm......
There's only space on the PCB for a 10mm diameter piece (when the caps are close together) and www.mouser.com shows no high uF caps at 10mm diam.
You can get 6.3v/3900uF aluminum Nichicon caps that are 12.5mm x 25mm for example.

If size becomes an issue, just run "short" wires from the caps solder pads to your caps terminals and then secure your cap to the board in any fashion you like.

Remember to keep the voltage rating the same.

[blinky]

thanks hellfire :thumbsup:


heres a pic of some cap mods done in parallel, it must have worked since he has some pretty nice clocks :D

http://upl.silentwhisper.net/uplfolders/upload8/Capmoddback.jpg

[Revv23]

i have a dead nf7 i could pull the caps off and solder in parallel on my dfi, but i like to use a case... hmm maybe i can cut the mobo tray to let the caps fit... then again, i doubt this will get me anywhere on air.. hehe...

after christmas i should have some extra cash so maybe some exotic cooling is in order

[lalPOOO]

If you're having trouble fitting caps on the front of the board put them on the back. Just cut holes in the motherboard backing plate.

[muzz]

Ummmmm there are dimishing returns according to theory if I remember correctly.
Years ago I used to build 2000v supplies (non switching- for grounded grid linear amplifiers/RF use), and the storage of the charge becomes an issue, where TIME is an issue.

Maybe my memory is incorrect, but I am fairly certain of this.

[STEvil]

Of course there are diminishing returns, thats just how things work.

The most important value of the capacitor (other than correct voltage and capacitance ratings) is the ESR value. There is a charging and a decharge ESR value in reality, but most of the time when you hear ESR around here its going to be referring to decharging rate. The lower the value the faster your capacitor can provide current to the device. Likewise the faster its ability to charge the more stable current its likely to be able to provide since it wont be in a constant charge/discharge state (this is why capacitance is important too, to create a buffer for short bursts of loads) which can actually cause the capacitor to explode or create a short internally.


Caps in car audio are the same as for computer hardware.. signal filtering and stable voltage supply ;)

[SPL15]

If you do cap mods, keep the leads as short as possible. Long leads totally defeat what you are trying to do with the caps and can greatly reduce the effect the cap has on noise filtering.

Also, several smaller quality caps are better ESR wise than one large one. Also mixing different types of caps and bypassing them with different types of "Bypass" caps can get you ESR specs below measurability and help stabilize the capacitance value and ESR across a variety of temperature situations.

I would not use general purpose capacitors cause they will degrade very quickly when used to filter high frequency noise. Look for caps made for Switch mode power supplies and have a large ripple current rating. Ripple current is the current in and out of the cap during every charge/discharge cycle that happens anywhere from 10 to 100 thousand times per second.

With switchmode power supplies, large filtering caps are really not necessary since the charge cycle period is extremely short. switch mode power supplies charge the caps thousands of times per second which drastically reduces the amount of needed capacitance for voltage support.

Caps do not supply reserve power for any meaningful amount of time unless you start getting into the farad values, but even then the useful voltage would be only about a quarter second when drawing several amps of current.

With switch-mode power supplies, the quality of the capacitance is much more important than the quantity since the caps in a SMPS are being used only for noise and ripple filtering.

The best improvement you can do cap wise is to put ultra high quality mica bypass caps and/or tantalum caps in parrellel with the exsisting caps. If your power supply is of decent quality you really shouldnt be worried about adding more capacitance to your board, but increasing the quality of the capacitance on your board is always a good thing.

adding quality capacitance inside of your power supply is a much better way to reduce ripple voltage and gets the problem where its started instead of 2 feet away on your motherboard...

Adding a larger inductance is a risky venture. Inductors oppose change in current so when your mother board demands a large transient in current, voltage will sag because the inductor is opposing letting more current through while resistance of the circuit is being reduced. inductors in series hurts transient response, but how much it effects it is arguable.

Also 99% of the mothernoards I see have places where caps used to be but were not placed due to engineering finding out they didnt need to be there for stable operation at normal clocks. i've seen the best improvements from simply adding the missing caps on my boards. adding the missing caps near the cpu sockets always have improved stability.

if you do cap mods dont get fixed on bigger is better, quality counts not quantity.

[Revv23]

^GREAT info

[scragley]

pc ice have you got any updates on that capicitor mod yet?

Ignore that lol just looked at the time differences between here and Australia lol, Let me know tomorrow :)

[kryz]

how do you decide which you change and by what you are replacing them?

[esdee]

lol ... just got back from my local elec. shop where i couldn't find 6.2V caps and i bought 16V ones.

pure luck i found this thread !

[SPL15]

I would highly recommend NOT using the cheap general purpose caps Radio Shack sells if your going to use them in switching power supply noise filtering purposes which is exactly what these caps will be doing on your motherboard.

Mouser electronics has no minimum order and sells lots of electronics components to hobbyests.

[[XC] moddolicous]

On mouser, dont you have to order something like $20 to make it worth while. Like I couldnt order just a few caps and have them shipped.

[charlie]

I ordered from mouser.com and got a bag of Nichicon

6.3v/2200uF
6.3v/3300uF
6.3v/4700uF

figure I'll have enough for future projects

[Holst]

Ive used those Nichicon 4700's in the past on modded boards with some success Charlie.

One point to note is that haing way too much capacitance can be a bad thing, especially on boot up.
As the voltage regulation on the board has to chage the caps up this can put an unusually high load on the voltage regulation.
I did mod an epox board that would trip the OCP uppon power up as I added so much capacitance. Had to disable to OCP to get it to power up. Even then the board OC worse than before as I had overdone the cap mod.

[Revv23]

Ive used those Nichicon 4700's in the past on modded boards with some success Charlie.

One point to note is that haing way too much capacitance can be a bad thing, especially on boot up.
As the voltage regulation on the board has to chage the caps up this can put an unusually high load on the voltage regulation.
I did mod an epox board that would trip the OCP uppon power up as I added so much capacitance. Had to disable to OCP to get it to power up. Even then the board OC worse than before as I had overdone the cap mod.


Good info...

BTW i've used DIGIKEY.com for pots and such before and i was astounded by the quality/speed of thier service... priced very fair as well. website is hard to browse though.

[SPL15]

Ive used those Nichicon 4700's in the past on modded boards with some success Charlie.

One point to note is that haing way too much capacitance can be a bad thing, especially on boot up.
As the voltage regulation on the board has to chage the caps up this can put an unusually high load on the voltage regulation.
I did mod an epox board that would trip the OCP uppon power up as I added so much capacitance. Had to disable to OCP to get it to power up. Even then the board OC worse than before as I had overdone the cap mod.


Yea Most people dont realize a cap becomes another load on the power supply and regulation circuits. When you power up, theres going to be a massive current surge to charge those caps. A cap is not a battery!!

a CAP filters noise and ripple by acting as a low impedance for AC current. The more capacitance you use, the more stress it puts on Diodes and rectification circuits because of a shorter charge time which skyrockets peak currents in rectification diodes.

I dont know how many times I gotta say it, but a cap is for noise/ripple filtering only. If your using a cap for energy reserve purposes, your wasting time and money, and could be hurting stability of your motherboard regulation circuits which will ultimately lead to a worse OC.

QUALITY OVER QUANTITY!!!!!!!!!!

[Hell-Fire]

Yea Most people dont realize a cap becomes another load on the power supply and regulation circuits. When you power up, theres going to be a massive current surge to charge those caps. A cap is not a battery!!

a CAP filters noise and ripple by acting as a low impedance for AC current. The more capacitance you use, the more stress it puts on Diodes and rectification circuits because of a shorter charge time which skyrockets peak currents in rectification diodes.

I dont know how many times I gotta say it, but a cap is for noise/ripple filtering only. If your using a cap for energy reserve purposes, your wasting time and money, and could be hurting stability of your motherboard regulation circuits which will ultimately lead to a worse OC.

QUALITY OVER QUANTITY!!!!!!!!!!



I would hope people know most of this by now...atleast for anyone that is considering doing any type of cap mod to their hardware. Then again, alot of people juse follow guides or try mods without knowing what is actually going on with the circuit loop components without bothering to learn about what is really happening. But it is important that most users here look at these types of things as abstractly as possible and leave the rest to more skilled people.

Regardless, a big part of this is whether the cap is in series of parallel with the diodes/rectifiers.

At the instant the supply is fired up those caps respond like a short...if a series connect is present for diodes...the current will be pretty high. Its the opposite for the parallel connect...all current will flow through that cap as the diode will respond like a short.

Thats only right after hitting the power switch of course.

With the larger capacitance, it is going to charge slower which will increase the current through any series component..diodes included. Again, the opposite is true for the parallel connect. And for petes sake, dont anyone connect caps in series unless you know what you are doing.

I really hope that anyone adding caps to a circuit is not doing so for the purpose of powering another device. Well, atleast not your average computer user that is. There are many applications where the cap is used to store charge for power usages.....but the big use is for the filtering of AC signal in DC applications. Thus a poor responding psu can be the result of faulty, poor quality capacitors that just arent up to snuff. You get enough spikes and say buh bye to stability. We saw this when chilly1 and FUGGER hooked up my PCP&C 510 Dlx to an O-Scope. Saw some nice 60mV+ spikes.

This is the kind of discussion that prob belongs in its own specific forum as most of what SPL has to say is well above the average modder. Maybe this wouuld be a good idea, then truly technical information is available by simply checking that forum.

[STEvil]

Sounds like an idea to me, you had mentioned trying to clean this place up a bit once before ;)

[Hell-Fire]

If I can only survive this week STE...lol.

I have some Guides in the works, as well as a review on a product. But getting killed right now...and thats no joke. 4 exams, 2 lab reports, 1 quiz, and 2 homework assignments....talk about hell to be me.

[LostInSpace278]

How would an average person, like me, measure the line noise on a PSU? Is there a special tool or do I need to call an electrician? (Which happens to be a friend, no charge)

I am really curious to how much noise is along the rails on my PSU's.


On another note, I have heard that on an NF7-S, cap modding has increased stabilty some. Is this true?

BTW, Thankyou for answering my questions about volt modding my NF7-S. All where successful!!!! :YIPPIE: (Vdimm, Vdd, and Vtt) Also modded my 9600 XT :rocker: I am having so much fun with a soldering iron, it should be illegal. My wife won't even let me turn on her puter any more :shrug:


Any one have pics of the vcore mod to this mobo? Just a pic of the area with what pins to connect. Not the pencil one either , I want to be able to more than 1.8~1.85 volts to it. I don't have the skills to add a 4th phase yet. I know I read it another post somewhere, Just wasn't explained very well.

[Hell-Fire]

Doesnt the NF7 have bios options above 2v for Vcore??

To be able to read the "noise" in your psu rails you will need to have access to an oscilloscope bud.

[LostInSpace278]

It has over 2v in the bios, but it fluctuates to much under load. I had read on another post about an IC chip, were by you connect 2 legs via a VR and it will control the fluctualtion a little better. And if your brave enough, you can add a 4th phase, for the best results.

EDIT: I believe its the one where you solder a 5k VR to pin 7 and pin 10 on HIP6301. Does this sound right?

[Hell-Fire]

Not sure if thats right or not honestly. I am in the middle of writing a 6-8 hour lab report and just checking the forums sporatically. Dont have time to check the data sheets.

Adding a resistor between 2 pins sounds like the standard droop mod to me. Would also help to consider adding possibly a choke near the 12v aux connector, and a couple of caps in parallel with the stock ones. Might help to filter out any additional noise.

[STEvil]

yup, choke and caps would help the board I think.

Got a 600w powerstream on mine and max I can get is 2650mhz 2.03v 2700mhz will run around in windows fine but once I put a load on it it crashes in about 5-10 minutes. Voltage doesnt help either... this is air cooled, too.

[LostInSpace278]

Well I took apart a PSU a week or so ago and found some low ESR caps on it. The mobo has 4 16v caps. Only 3 16v caps in the PSU. I do have enough for the 6.3 caps. Would doing these help as well or just stick with doing the 12v caps? I see the choke your talking about, the tiniest on the board? Its a tight squeeze in there, will it matter if it touches anything, like the cap or the plastic shroud for the 12v Aux line?

I can do about the same as you STEvil, but only need 1.95 vcore.(on air as well) This is with a Antec True 430. I am just trying to cure the fluctation problem. Maybe later on If I go water chiller, DI, or direct die, I may need more, but right now I am good.

[STEvil]

voltage isnt the important number (other than it should be higher than what the max the cap will have going through it), and you have to keep track of what each capacitor you are replacing or adding to does. Some circuits wont be able to handle the extra capacitance so well due to lower requirements vs what a CPU would need. Most of the 6.3v caps will be for vdimm or the northbridge or agp (just did an 8rda+ today, replaced every 6.3v cap on the board because they were all buldging and leaking).

Wish I had more room under my board so I could add another choke and a couple more caps..

[LostInSpace278]

So I can add the choke under the board? I just solder it to the existing choke?

I have read that on the capacitors, I need to keep the legs as short as possible, is this correct? how do I check the voltage comming from the capacitor? Can I take out my video card, flip the mobo over and turn it on? I haven't even bothered to put the mobo back in the case, I figured as many things as I want to do to it, it would be a waste of time!

[SPL15]

By putting another choke in parrellel with the existing inductor, your going to be greatly reducing the inductive component of the PI filter (CLC filter). This will lower it's noise filtering capability and by adding another core in parrelel to the existing one, your going to be increasing saturation current of the total inductance which may prove to also be highly detrimental to noise/ripple filtering in addition to the lower inductance value of the chokes in parrelel which will hurt noise filtering. Know what your doing before you do it.

Also, VOLTAGE IS NOT COMING FROM THE CAPACITOR!!!!!!!!!!!!!!!!!!!!!! The power supply produces pulses of current which are FILTERED by caps!!! Caps are not batteries!!! They hold a static charge, they dont hold enough energy to power a high current draw for any meaningful amount of time. If your trying to relying on caps to make up for a crappy power supply, there's a simple solution to it and I hope you guys are bright enough to figure it out. Caps on motherboards should ONLY be used for noise filtering. Again, know what your doing before you do it.

If you hook up a scope to your computer, KNOW HOW TO USE IT!! depending on your grounding situation, you can do anything from getting false results to destroying the scope and computer. I highly recommend isolating the scope's ground connector. Also, your ripple measurements with a scope will be WAY off if you stick the ground on one point and put the probe somehwhere a foot away. Just cause ground is supposed to be the same throughout the system, doesnt mean it is. Again, know what your doing before you do it.

[STEvil]

How do chokes respond to current load, SPL15? Oppainter has had a choke unsolder itself due to heat on his x800 series card and I am wondering if part of the problem on the nF7 is the choke by the P4 connector cant handle the current? I also have a dead 9700 card and one working one and have considered placing the chokes from the dead card in parallel with the ones on the good card to see if I can increase the voltage regulation circuitry on the card somewhat. Adding caps only had minimal gains..

Glad to have you here btw, I only know enough to be dangerous :D

[Revv23]

im pretty sure replacing a small choke with a nice big looking one couldnt hurt to much...

[SPL15]

im pretty sure replacing a small choke with a nice big looking one couldnt hurt to much...


How do you know this??? Do you know what it does? Why its doing it? and how much it is doing it? Statements like these spread bad information and bad information is virally rampant in consumer electronics especially where enthusiasts are involved. I urge you to make statements that are true based on real knowledge NOT because it seams like it would work because it is bigger which obviously means it is better.

As for STEvil's question, I wont go into inductor physics because it would take an hour for me to upload the massive post needed to throughly explain how they work. Basicaly an inductor acts as a low impedance to low frequencies and a gradually rising impedance to frequencies higher in frequency. Inductors do this because they have a magnetic field that must be opposed/chagned in order to change the current through the coil. Inductors reduce high frequency voltage by -6dB per octave above the crossover frequency. The crossover frequency is determined by the frequency value where the load impedance matches the inductor impedance. This is a very very very basic decription of the function of an inductor.

A low pass filter (Which an inductor is) has a higher impedance to fast high frequency votages which is good for noise/ripple filtering but can be bad for cases where a fast transient response is needed like in a power supply.

In a power supply filtering application, the choke is just about always ran in saturation mode which in very simple terms decreases it's impedance to fast current pulses, but maintains it's ripple/noise filtering abilities decently. If a choke is in saturation, it's ferrite core cannot be magnetized anymore than it is. Air-core chokes are almost immune to saturation because they have no ferrite core to be magnetized.

A choke gets hot because of the coils of wire dissipating power.... Duh. The coils dissipate power because of the natural resistance of copper (DCr ~ Direct Current Resistance) and the reactive impedance (Xl) of the inductance of the coils when DC current with AC ripple flows through them. Let's only factor in the Direct current resistance and say one of the output filtering inductors on a three phase motherboard has a direct current resistance of .02 ohms (Which is probably unrealistically low). Power = Current Squared times Resistance (P=I^2*R) so lets say your running a highly overclocked prescott which will draw around 90 amps from your motherboard power supply which divided between 3 phases equally (Which is also very unlikely) will equal 30 amps per phase. So this give us 30 amps squared times .02 ohms which will equal 18 watts being dissipated by the inductor in a perfect world during perfect conditions. 18 watts is a lot of power when there is little surface area to dissipate the heat. In the real world the heat dissipation will be much higher.

What I've done to my motherboards was rewind the inductors with a SLIGHTLY lower inductance and SLIGHTLY larger cores with multiple strands of enamal coat wire that equal a much larger cable diameter to lower DCr. BUT if your having inductors unsolder themselves from the board, then your either vastly exceeding power design limits of the board, or the board was designed for cheap manufacturing costs or both.

[LostInSpace278]

Well you have done a nice job on your board. As you know what you are doing.

We or I was looking for a way to control the fluctuation on the vcore, in a simple yet effecient way. Please feel free to school me in the art of choke rewinding. A few links to the products I would need, would be most helpful.

[STEvil]

Makes sense as to why chokes sometimes "squeal" then.. can squealing be an indication you are beginning to run too much current through it maybe?

LostInSpace - vdroop mod takes care of vcore fluctuations much of the time, although it might drop your max vcore somewhat (selecting 2.3v would result in 2.1v max for instance). On the DFI Infinity and LanParty-B this was done by soldering to a VR (10K max) or a fixed resistor between 2K and 5K from the output side of one of the chokes supplying vcore to the vsense pin for vcore... I believe there is a guide for the nF7(-s) in the mod forum also..

http://www.xtremesystems.org/forums/showthread.php?p=633773#post633773
http://www.xtremesystems.org/forums/showthread.php?t=21796&highlight=nf7%2A+vdroop

those two links have mention of them, dont know how valid the first link is and I havent read the second one yet...

Thanks for the schooling SPL15, looking forward to futher info :D

[SPL15]

I think the question should be is the fluctuating VCore that the BIOS, MBM, etc report an accurate reading? When I viewed my VCore on my fully calibrated/certified tektronixs scope, it didnt look nearly as bad as MBM makes it look. My min max range was 1.4-1.44 with this prescott with the voltage set at auto in the BIOS and had an average Peak to Peak ripple of 11 mV. RMS ripple was calculated by the scope to be only 5.4 mV!!!! considering how much current is drawn by the CPU and the noisy environment, this is very respectable by any standard. MBM5 however during the same time frame showed my VCore min/Max as 1.36 to 1.48 volts.... I will believe my $20,000 DPO scope that does 20 GigaSamples per second over free monitoring software anyday.

You have to remember the chip on the motherboard that is getting this information is being subjected to all the EMI/RFI and ground noise the computer is producing. This isnt a good thing for accurate and precise measurement. I would use this mainly as a reference and not an absolute measurement for basing decisions and effectiveness of mods.

Squealing Inductors are caused by coils resonating from the lower frequency/longer duration current pulses from the switching mosfet. When current demand is high, the PWM IC gives the switching mosfet lower frequency,high duration voltages on it's "gate" lead. Since we now know the filtering on the mosfet's output is a low pass filter, we should be able to figure out that the switching lower frequency will have a lower impedance to the filter AND a longer charge duration due to the lower frequency and longer pulse duration thus enabling voltage to stay constant which will mean more current will flow when the resistance of the load is dropped.

Most things run in constant voltage mode, this means output impedance of the supply power source is 0 ohms (In a perfect world). When load resistance drops, current rises and voltage stays 100% the same. We dont live in a perfect world though, so the power source's output impedance is not 0 ohms. there are parasitic resistances I've talked about before and these resistances are in series with the load creating a voltage divider. As the load resistance drops, the ratio of parasitic resistance to load resistance drops which simply means that the voltage across the parasitic resistance grows and the voltage across the load drops (Like Vcore).

Now seeing as how the inductors are in series with the Vcore, and the inductors are running VERY hot, there has to be a voltage drop across these inductors in order for them to be getting hot. Here is one of the main parasitic resistances of the Vcore. We all know that noise and ripple is bad for stability, but we also know that voltage drops can have the same effects. What do you do??

People who know basics would think the magical capacitor will solve all their problems, because they are taught a cap is a energy storage device, which it is, but a very very small energy storage device that stores a static charge. They are not batteries! can you power up a 100 watt light bulb (which takes less power than a CPU) for any appreciable amount of time by shocking it with your finger? NO!!! I'm not saying dont do cap mods, but know what they are doing. At the frequencies and current the power supply is working at, the length of the leads on the caps (mm count) will make or break the effectiveness of these caps, and 99% of the mods I've seen have lengths that render the cap worthless. On amplifiers I've designed and built, a few millimeters of lead length on filter capacitors made a distortion difference of 0.3% at 20 KHz which is massive. Computer power supplies/regulation circuits works at 20Khz and above. The purpose of caps on motherboards is for FILTERING purposes ONLY. It makes sense to spend time making it quality filtering NOT QUANTITY.

So the inductor is the main source for VCore drop due to parasitic resistance. what can you do about it? Well I'm fairly certain that Asus and Abit dont have an inductor making factory so they have to be buying these parts from someone else. There are many catalogs with pages of inductors to experiment with. Digikey, Mouser, MCM, Allied, etc. have pages of inductors that would work. If you have the gonads to roll your own. you can take the coils from your motherboard or a dead one and cut all the wires off, but remember how many turns there were. You then need get small diameter like 22 Gauge enamal coat wire and use several strands about 6 or so to wrap around the core the same or ONE turn less than what was on there before. your basicly making a larger gauge wire from mulitple smaller gauge wires. MAKE SURE your windings are nice and neat!!! it matter !! also different winding patterns have different effects on parameters. you may want to do some searches on google about it, cause I'm not going to go into inductor physics in a computer forum.

I've taken this thread way off topic so I'll quite now before I get booted.

[SPL15]

Makes sense as to why chokes sometimes "squeal" then.. can squealing be an indication you are beginning to run too much current through it maybe?

LostInSpace - vdroop mod takes care of vcore fluctuations much of the time, although it might drop your max vcore somewhat (selecting 2.3v would result in 2.1v max for instance). On the DFI Infinity and LanParty-B this was done by soldering to a VR (10K max) or a fixed resistor between 2K and 5K from the output side of one of the chokes supplying vcore to the vsense pin for vcore... I believe there is a guide for the nF7(-s) in the mod forum also..

http://www.xtremesystems.org/forums/showthread.php?p=633773#post633773
http://www.xtremesystems.org/forums/showthread.php?t=21796&highlight=nf7%2A+vdroop

those two links have mention of them, dont know how valid the first link is and I havent read the second one yet...

Thanks for the schooling SPL15, looking forward to futher info :D



If you need more than 1.8 volts to the CPU, you will need to change the surface mount tantalum caps in the CPU socket if it has them. They are rated at 2 volts or 1.8 If I remember correctly. Tantalum caps do not like out of spec voltages, ripple currents, and high heat. They also like to flare up when they are abused so it would be wise to change them. Also tantalum caps are the highest quality cap money can buy, but they dont like abuse and will degrade very quickly if not ran within tolerances.

[STEvil]

Very good info and definately not off topic ;)

Tantalum caps not liking above ~2.0v would certainly answer for why some boards run great for long times at or above ~2.1v then deterriorate.

[SPL15]

Very good info and definately not off topic ;)

Tantalum caps not liking above ~2.0v would certainly answer for why some boards run great for long times at or above ~2.1v then deterriorate.


Just wanted to clear up that those caps I'm talking about are RATED for 1.8 volts max and that is why they do not handle higher voltages, it is not because tantalum caps do not like over 2 volts as there are tantalum caps rated for 50 volts, although they are large and EXPENSIVE!!!. Tantalum caps like to short out and burn up when they fail. This is usually precluded by a skyrocketing ESR which basicly makes its high frequency filtering capabilities worthless.

Tantalum caps are the best money can buy quality wise, but they are very unforgiving of abuse.

Any cap no matter what type is supposed to be ran within 20-80% of its rated voltage. This is especially true for Electrolytic caps because the Dielectric will not form/maintain correctly if there is not at least 20% of the rated voltage present during normal usage.

On caps you see a tolerance rating, most people know that this is for capacitance value tolerance, but few people realize that this also applies to WVDC (Working voltage Direct Current), Ripple Current, ESR, Dielectric Absorption, and all other specs of a cap. Running caps at the edge of voltage ratings and Ripple Current ratings will always mean bad news sometime down the road. A high ESR reading signals a failing cap usually caused by excessive ripple current... But I doubt any of you have a Capacitor ESR meter which kinda leaves ya in the dark.

[LostInSpace278]

I think the caps you are refering too are like these (http://www.xtremesystems.org/forums/showthread.php?p=538987#post538987)

I did a google search and there are many types of tantalum caps, most of the varieties you see used on mobos. I am just making sure I am following correctly.

[SPL15]

I think the caps you are refering too are like these (http://www.xtremesystems.org/forums/showthread.php?p=538987#post538987)

I did a google search and there are many types of tantalum caps, most of the varieties you see used on mobos. I am just making sure I am following correctly.


Umm... no I think your lost in space :D .

If you're refering to the small brown surface mount caps on the backside of the motherboard under the CPU, those are just cheap surface mount ceramic capacitors and probably have a voltage rating of at least 50 volts probably much much higher so you dont need to worry about them.

I'm talking about surface mount tantalum caps that are found sometimes in the center of the CPU socket on 478 socket P4's. They are black and one side has a line acrossed it or is white to signify postive.

I'm really not too sure why you would want to put 2 volts or more into a P4 anyways.

[LostInSpace278]

Well not sure if I would more than 2v into a P4 but mine is an 2600+ mobile. I am running air and have already put over 2v into it. For a brief period of time any way.

I chose that picture, because when I did a google search for tantalum caps, I found a site that had the ones you refered to above as well as the orange looking caps. I do know the caps you talking about, next time I have my cpu out, I'll take a gander in the socket. Guess I had better do some more research first.

[STEvil]

usually just ceramic caps on AXP boards.\

SPL15, I have been wondering if the reason nF2 cannot do high FSB could be related to the fact the northbridge is fed both by CPU voltage and by the VDD power circuit, but one or the other is not supplying clean enough voltage to it? Would a tantalum cap in parallel with the stock electrolytic caps (6.3v 1500uf x1 from cpu vcore supply, 6.3v 1000uf x3 from vdd) be worth trying maybe?

[SPL15]

usually just ceramic caps on AXP boards.\

SPL15, I have been wondering if the reason nF2 cannot do high FSB could be related to the fact the northbridge is fed both by CPU voltage and by the VDD power circuit, but one or the other is not supplying clean enough voltage to it? Would a tantalum cap in parallel with the stock electrolytic caps (6.3v 1500uf x1 from cpu vcore supply, 6.3v 1000uf x3 from vdd) be worth trying maybe?


I guess you could try it, but no cap regardless of quality can fix design flaws/Limitations of a PCB, Chipset, CPU, Power Supply, Layout, Software, etc.

Capacitors aren't bandaids and shouldn't be used like one. If your getting astronomical gains from adding caps, then I would move to different hardware because that clearly shows a really crap design. Also, if the filtering was that bad to begin with, it is likely that you'd see problems at stock settings.

Now caps do deteriorate over time especially with switchmode power supplies so if your caps are going downhill, then new caps would make a difference. Hopefully your motherboard maker is using good caps...... Abit

I'm thinking the NF2 doesnt do ultra high FSB is because of an Architecture reason, not because of noise and ripple on voltage lines. The AMD platform is not known for it's headroom like Intel is. NVidia designs a chipset that is good enough and bit more because that is what AMD tells them to do. Intel designs one that has massive headroom because they design for rock solid stability. Notice that VIA and SiS Chipsets for Intel dont do as well as Intel's chipsets. kinda the same thing with AMD and their chipset makers. You care the most about yourself, so if your building yourself a chipset, your going to make it a good one.

Also It may not even be the chipset, it could very well be that the Athlon XP 's architecture CPU wise doesnt handle higher FSB's well. The NF2 chipset may do 2.6 bagigaherts 110% stable, but if the CPU's FSB interface can only handle 420Mhz, then that is the limiting factor.

[STEvil]

people have had AXP's to 300mhz but the northbridge cant handle it. nVidia's nF2 chipset does ok on 2x256 but once you throw 2x512 on there its all downhill. Bumping up VDD can help sometimes, more for some than others.

We already know its the chipset primarily, but I am wondering if the voltage regulation isnt part of that "build it good enough to work and dont worry about overhead" since it wouldnt be the first time nVidia or an AMD board was built like that.

Guess i'll have to see what i've got around for tantalum caps maybe.

[SPL15]

people have had AXP's to 300mhz but the northbridge cant handle it. nVidia's nF2 chipset does ok on 2x256 but once you throw 2x512 on there its all downhill. Bumping up VDD can help sometimes, more for some than others.

We already know its the chipset primarily, but I am wondering if the voltage regulation isnt part of that "build it good enough to work and dont worry about overhead" since it wouldnt be the first time nVidia or an AMD board was built like that.

Guess i'll have to see what i've got around for tantalum caps maybe.


If voltage regulation problems on NF2 boards ARE in fact the reason for mediocre FSB (Although I'd say 300Mhz is dam good) Caps arent going to solve the problem. Again, Caps dont make power, they are helping to filter the DC pulses from the Switching mosfets. The biggest component of the filtering is the output choke. In series, a choke acts like a capacitor in parallel to the load so you dont want to go real low with its value, BUT a choke is also a series resistance, so you dont wanna go to high. TO the power supply, a choke in series with the load acts as a high impedance to high frequency while a cap in parallel to the load acts as a short to high frequency. Do you see how they are both acting as low pass filters??

Ya never know though, a cap may gain you a few extra MHz, but I would not expect anything large from it.

[dippyskoodlez]

If voltage regulation problems on NF2 boards ARE in fact the reason for mediocre FSB (Although I'd say 300Mhz is dam good) Caps arent going to solve the problem. Again, Caps dont make power, they are helping to filter the DC pulses from the Switching mosfets. The biggest component of the filtering is the output choke. In series, a choke acts like a capacitor in parallel to the load so you dont want to go real low with its value, BUT a choke is also a series resistance, so you dont wanna go to high. TO the power supply, a choke in series with the load acts as a high impedance to high frequency while a cap in parallel to the load acts as a short to high frequency. Do you see how they are both acting as low pass filters??

Ya never know though, a cap may gain you a few extra MHz, but I would not expect anything large from it.


Hmm.. 300mhz is **rare**, but its known that the CPU isnt the problem, or, shouldnt be atleast... My 2600+M has handles 267fsb form my infinity, but my an7 has voltage issues and cant maintain 220 stable.

The outlet im on isnt quite the best, so Part of my problem may be jumping voltage... feels like 220 can be stable some times, isnt others... 1.65vdd->1.75Vdd does nothing..

I see what ya mean by a cap filtering instead of holding power-- AA's can't power a monitor for long :p:

I really wish Nvidia would give datasheets for the NFII stuff. :toast:

[kristos]

We already know its the chipset primarilyIf it's the chipset, then why does just about every DFI do 250 fsb or more whilest NF7's more often then not don't make that number stabely.

[dippyskoodlez]

If it's the chipset, then why does just about every DFI do 250 fsb or more whilest NF7's more often then not don't make that number stabely.

PCB layout... SMD selection, BIOS?

Or just maybe special NB's? :p:

That just proves it IS the chipset--

DFI didnt engineer the LP and infinity like an AN7 or NF7.

[STEvil]

Doing a couple mods similar to this seems to help the Abit IC7 series, so just speculating really.

http://www.xtremesystems.org/forums/showthread.php?t=28553

How do I decipher the text on SMD tantalum capacitors? Got some that say "226c p5 1xc" on them but dont know what everything stands for and google hasnt turned up much yet.

[SPL15]

How do I decipher the text on SMD tantalum capacitors? Got some that say "226c p5 1xc" on them but dont know what everything stands for and google hasnt turned up much yet.


Different manufacturers have different codes. I have a hard time deciphering them too, so usually I dont :D . My guess would be that it is a 22uF at 6 volts and the p5 1xc has to do with the size and series of cap. Dont quote me on this though.

A lot of multimeters have a built in capacitance meter which will tell you the value, which will help you narrow down what number will be the voltage.

[STEvil]

Doesnt seem any of my multimeters have a capacitor tester setting on them.. hm.

[Hell-Fire]

The only other way, that I can think of off the top of my head, to determine the capacitance is to charge the cap to a specific voltage and see how long it takes the capacitor to discharge across a resistor.

I take it this is a capacitor that is already on a board and not something just laying around.

In any case, we can prob still that little experiment and determine the capacitance if ya really wanna. Not a hard thing to do.

[SPL15]

The only other way, that I can think of off the top of my head, to determine the capacitance is to charge the cap to a specific voltage and see how long it takes the capacitor to discharge across a resistor.

I take it this is a capacitor that is already on a board and not something just laying around.

In any case, we can prob still that little experiment and determine the capacitance if ya really wanna. Not a hard thing to do.

That is a way to get a rough estimate on capacitance, but you'll get a lot of error because there is a huge variable in time (Using a stopwatch) and when the cap is "Discharged" (How many RC tmie constants??). Also Dielectric absorbtion will have a big impact on the measurement with this testing method.

The best way is to apply a Known AC signal to the cap in series with a variable resistor. Adjust the Pot until the voltage across the cap is equal to the voltage across the pot. The resistance of the pot will be equal to the Impedance of the cap at that particular frequency when votage is equally divided between the two. If you know the frequency and the Capacitive impedance, you can calculate capacitance. This is the same method used by real capacitance meters and is very accurate. In cap meters they use a fixed resistor instead of a variable one and a high frequency.

The best way though is to just get a meter with a capacitance measurement

[yasoumalaka]

Ever since I implemented a droop mod with minimal gains I've been toying with the idea of doing a CAPS mod. I've located capicitors with the same uf and voltage, but I'm not sure how to judge them on other aspects. Could somebody tell me if these are good for use on mobos. I ordered them at digikey.com. Thanks. Peace!

Part#: P11206-ND
digikey.com (http://www.digikey.com)

[Hell-Fire]

Ever since I implemented a droop mod with minimal gains I've been toying with the idea of doing a CAPS mod. I've located capicitors with the same uf and voltage, but I'm not sure how to judge them on other aspects. Could somebody tell me if these are good for use on mobos. I ordered them at digikey.com. Thanks. Peace!

Part#: P11206-ND
digikey.com (http://www.digikey.com)


Be weary of adding to much capacitance to any circuit loop. The more capacitance you add the slower that cap will charge and the higher the current will be for that loop for a longer period of time versus the stock conditions. If you are adding caps that equal the stock, you should be fine as many people have done this with success.

As for the rated voltage, as long as its rating is above the voltage that will be applied to it all will be right with the world.



That is a way to get a rough estimate on capacitance, but you'll get a lot of error because there is a huge variable in time (Using a stopwatch) and when the cap is "Discharged" (How many RC tmie constants??). Also Dielectric absorbtion will have a big impact on the measurement with this testing method.

The best way is to apply a Known AC signal to the cap in series with a variable resistor. Adjust the Pot until the voltage across the cap is equal to the voltage across the pot. The resistance of the pot will be equal to the Impedance of the cap at that particular frequency when votage is equally divided between the two. If you know the frequency and the Capacitive impedance, you can calculate capacitance. This is the same method used by real capacitance meters and is very accurate. In cap meters they use a fixed resistor instead of a variable one and a high frequency.

The best way though is to just get a meter with a capacitance measurement

SPL15, there is no argueing your knowledge in this field, but some of these suggestions are beyond the scope of what most users here can do. Thats not saying our members are not intelligent enough to do them, but we need to provide the methods for them to do it for themselves. Asking them to start using AC signals across a circuit loop in order to estimate the capacitance is just not feasible for most I would think. This may be Electrical Engineering 101 I know, but most members here are not electrical engineers.

I would agree that using a multimeter is a way to go, but only if someone already has one, or plans to buy a new one. Our job (mine, yours, others who understand it), is to provide them ways to do simple experiments in order to figure some of this stuff out for themselves. That experiment is a very handy way to figure out a solid estimate for capacitance in conditions where it is not readily marked on the actual capacitor.

If you charge the cap to a fairly high level (5v or more), and have a multimeter that tracks to atleast 0.001, and you use a fairly large resistor, the discharge will be slow enough to get a good estimate of the capacitance. You can get to within 1% of the rated capacitance if you do the experiment correctly. I would say 3-5 runs is more than sufficient. Generating that number of RC constants will yield a solid estimate.

Unless you have a function generator, forget about applying a sinusoidal waveform...and I figure most people do not have these in their homes. And most people will not have access to these at school either.

If you have the true resistance of your series resistor, not rated, and do the experiment properly you will get a very good estimate of the capacitance. Not to mention very few capacitors are truly accurate to their rated capacitance to begin with.

Man oh man do we need a "Xtremely Techinal" forum as this topic is above most users knowledge.

[yasoumalaka]

Are those caps of the right quality.

[SPL15]

Man oh man do we need a "Xtremely Techinal" forum as this topic is above most users knowledge.

Ha Ya I'm with ya there. I understand that alot of what I say is pretty technical, but from my viewpoint, when you do a mod, you should know what it is that it is doing. Maybe not exactly specifically what it is doing, but a general idea of what is happening so they can better troubleshoot problems that arise other than wasting server space with a thread that reads "I F'd up my board doing a mod and all the solder pads are burned to hell, Can someone tell me what I did wrong and help me fix this irrepairable board I screwed up because I rushed into something I had no knowledge about?"

Even if the people here can not do the test I described above, it is a good example of how a capacitor opposes AC frequency. I really doubt most people have the knowledge here to really grasp everything I'm saying but hopefully the confusion of what I say inspires them to learn more and experiment on their own to gain knowledge. I really can't stand it when people do a mod just because it supposedly gains performance and then see pics of the mod and it has so many things wrong that it renders the mod useless. The more knowledge the users here have, the better the quality of information.

I know for a fact that there are users here that want to know the in depth details of how the electronics are integrating with each other, but so far they kinda have to rely on stumbling across a rare good post. I think a dedicated area where highly indepth postings is a really good idea, but it would need to be highly moderated to insure that posts that read "Where's the link to the Vdroop mod for the P4C800 at?" will not be tolerated. It should be dealing more with the electronic theory as it pertains to computers, and not procedural topics on how to do a mod.

Look at the Phase change forum, I would say that the info there is pretty dang technical and I personally have learned just about everything I know about phase change from those forums. I now have the knowledge to do anything and everything that would be needed to set up a single stage system. Highly technical information is vital to the quality of a forums usefulness.

[yasoumalaka]

How do I know if a cap has a low ESR?

[Hell-Fire]

How do I know if a cap has a low ESR?


As far as I can recall, the ESR for a capacitor is based on the internal resistance of the electrolytic used (as well as the plates etc etc), and the very small resistance of the connecting external legs. This forms the caps Equivalent Series Resistance (ESR).

The ESR is very low for a good capacitor, and only diminishes over periods of years....or major wear and tear. There are many other things that affect the ESR, but not a topic to talk about now. One of the major things however, is temperature. High temps can either damage the rubber seal or begin drying the electrolytic out. This causes the ESR to increase. Circuits are setup with specific resistances in mind. So, if a cap initially has a very low resistance, it will not affect the circuit. However, if the ESR begins to rise in the cap, that will affect the charging time of the cap as well as its ability to subdue AC signals. What you end up with is the resistane already present in the circuit, as well as a "series resistor" inside the capacitor. Basically it cant do its job properly. Not to mention caps that take abuse over extended periods can actually explode...literally.

Power supply caps are prone to this type of failure as they have to endure large ripple currents which heats the electrolytic beyond its tolerance and it begins to break down. Thats why 6 outta 10 psu failures are due to blown caps.

Unless I am mistaken, just check the resistance between the pins of the cap.

Maybe SPL can verify what I said above.


You could not be more right SPL.

Hopefully some members will take it upon themselves to have a look around the net and their locl book store. There is no replacement for knowledge...period.

The first step in being able to figure out mods on your own, and troubleshooting mods that arent working, is know wth is going on behind the scenes. Something as simple as how resistors/caps respond once in series and parallel is lost on many people here.

Soon as I get some free-time I will talk with FUGGER to see about setting up a technical forum here. Cough:: throw your hat in for Modship ::

I agree that tech replies may force some members to do the right thing and grab some knowledge, but I would wager most just follow guides and close their eyes to learning what is truly making that wonderful mod tick.

In any event, I for on thank you for your expertise and time invested here....so please dont think I was giving you a hard time.

[persivore]

How do I know if a cap has a low ESR?
You have to measure the ESR using a special meter designed for reading the ESR. You might be able to find info about a caps ESR by looking at the caps datasheets, but that would only tell you the ESR that the cap is designed to have, and not its true value after hours of (ab)use.

[STEvil]

sometimes they say "Low ESR" right on them, although its not a very technical description of the actual esr rating.. ;)

[yasoumalaka]

I attend UF so I could take classes in circuitry but I'd rather just read a book. Do any of you guys have suggestions? I would really like to learn a few things before my next build. That way I could mod it from the jump.

[dippyskoodlez]

I attend UF so I could take classes in circuitry but I'd rather just read a book. Do any of you guys have suggestions? I would really like to learn a few things before my next build. That way I could mod it from the jump.

www.google.com

Google knows all. :banana4:

[STEvil]

Added the SMD tantalum to the board, didnt help any. Even tried feeding the northbridge 2.6v and still nothin'... argh.

nForce2 have to be one of the most aggrivating chipsets there is.

EDIT

considering putting the spare SMD tantalums off my dead 9700np onto my living 9700 pro now.. :p:

[SPL15]

I attend UF so I could take classes in circuitry but I'd rather just read a book. Do any of you guys have suggestions? I would really like to learn a few things before my next build. That way I could mod it from the jump.

Books are great, but there is no substitute for in class instruction. throughout my schooling I learned absolutely no new concepts i didnt know about before, but class was invaluable in tightening up my grasp on things that were a little fuzzy. Also the hands on experiance of class is more helpful than any book for people with no background in electronics. People say the stuff I post on these forums is technical but compared to some of my text books from college, my posts are as easy to read as "The Cat in the Hat" by Dr. Seuss.

If you can afford it, I would highly recommend classes, who knows you may find a career out of it (a very high paying career too :D )

[kristos]

who knows you may find a career out of it (a very high paying career too :D )Is there that much money to be made in electronics (in the US)? :D

Not that that should be your main reason, if any, for getting into electronics, I'm just inquiring :)

[SPL15]

Is there that much money to be made in electronics (in the US)? :D

Not that that should be your main reason, if any, for getting into electronics, I'm just inquiring :)

Depends on where you are. In my area, there are few talented electronics engineers and few good electronics technicians. Means good money for people that are talented around here, but also means companies are more likely move to somewhere there is lots of cheap talent..... like China

[yasoumalaka]

I just did a caps mod on my DFI lanparty. I added 13 caps in total and when I went to fire it up I got a quick flash from my led fans and that was it so after messing around with various wires and stuff it still didn't work so I startesd to take of caps. The first two I took off where right next to the 2 12v lines going into the board after this it worked. This left me with 11 caps. When I look at tutorials on caps mods on the 478 they only use 11 caps is this strange or is there something behind it. I thought maybe one of you might have the answer. Peace!

[SPL15]

I just did a caps mod on my DFI lanparty. I added 13 caps in total and when I went to fire it up I got a quick flash from my led fans and that was it so after messing around with various wires and stuff it still didn't work so I startesd to take of caps. The first two I took off where right next to the 2 12v lines going into the board after this it worked. This left me with 11 caps. When I look at tutorials on caps mods on the 478 they only use 11 caps is this strange or is there something behind it. I thought maybe one of you might have the answer. Peace!


It's just a coincidence, there's nothing significant with the number 11 except that it is one more than 10 and one less than 12 :D .

The reason your board wouldnt power up could be caused by several things or a combination. Your power supply has a current limit. If it is sensing a massive current rush when you power up, it will shut down in order to save itself and connected equipment. Also, you've got to charge those caps, if your power hasnt stabilized and fully charged the capacitors in say 300mS (Spec'd for PCP&C 510) the "Power Good" (AKA PG) signal will not go to 5 volts and the motherboard will unlatch the "Power On" signal to the power supply which stops the oscillator in the PWM IC. The "Power Good" signal from the power supply releases the motherboard's internal reset latch thus starting the boot-up process. There is a Monitor IC in every AT and ATX power supply that monitors voltage/current conditions. If something is not kosher, this Monitor IC will stop the PWM IC from PWMing and drop out the "Power Good" signal. If you look closely I bet you'd find a 16 DIP IC that is manufacturerd by ASTEC in a whole poop ton of power supplies. This will be the monitor IC.

Also, your motherboard could be sensing an out of spec voltage drop after 250 mS (Industry standard) which is a function of current draw. More capacitance creates a larger initial current draw when you power up, If the motherboard monitoring hardware senses that there is a large voltage drop after the predetermined stabilization period (250mS), it will unlatch the "Power On" signal that goes to the power supply (Green lead from power supply). Larger capacitances take longer to charge up due to voltage drops across parasitic resistances in the power loop which effectively lengthens the RC time constant which determines how fast a capacitance charges. If the world was perfect you could magically get rid of all the parasitic resistances in your system and you'd have no Vcore droop, Vdimm Drop, no voltage drops period and much less heat as long as your power supply could provide the amperage needed which woldnt be hard since the power supply would be 100% efficient which means no heat.

I'm glad we dont live in a perfect world though cause I'd be out of a job and you guys would be out of a hobby :D .

[yasoumalaka]

After playing around with the bios the highest stable clock I'm able to achieve is 3.82. Does anybody think it would help to try CAPs with different uf.

[persivore]

After playing around with the bios the highest stable clock I'm able to achieve is 3.82. Does anybody think it would help to try CAPs with different uf.

After a certain point, no matter how many caps you use, you will start to reach a point where you will see no benefit from adding more caps, and you might even start to see a decrease in performance. You might have reached this limit if you are getting boot problems with 13 capacitors. Adding capacitors will never be able to make up for a power supply, it will just help to improve it slightly. Are you sure that it is the Vcore regulator which is limiting the overclock and not some other factor?

[yasoumalaka]

No I'm not sure, but I know others have had sucess with different combimations of capacitors. I solved the boot problem. My overclock is still relatively weak for this processor, mem, moded mobo and psu. In addition I have a processor that nebver gets over 44c. I'm thinking of posting my bios screens somewhere. Maybe I've got a setting wrong somewhere. After ruling everything out I migh just see if the proc can handle 1.5v or more and whether this helps. Thanks for any suggestions. Peace!

[persivore]

You could try putting some smaller value caps (tantalum caps maybe) as close to the CPU's Vcore pins as possible.

[SPL15]

After playing around with the bios the highest stable clock I'm able to achieve is 3.82. Does anybody think it would help to try CAPs with different uf.


Capacitors are not magic band-aids that fix limitations in your system. If your CPU is running at its max at a particular temp/voltage, caps will do little if anything. Spend your money lowering temps, not increasing capacitance.

3.82Ghz is not bad if your running air. I'm assuming its a P4 since 3.82 for AMD would be pretty ridiculous.

Until you start getting into high bus/CPU speeds, I wouldnt bother with voltage mods and capacitor mods.

Here's an analogy, Doing major mods to a motherboard running a relatively low bus would be like putting a full ultra performance race suspension on an Acura Integra with stock rims/tires and a motor putting out stock horses for an 80 year old lady. It doesnt make much sense to spend all that money/time on an ultra performance suspension when your performance is being limited by a lack of tire traction/sidewall flex and a puny 110 Horsepower engine rated at the flywheel AND a driver who doesnt quite know how to manipulate the car to bring out performance..... Also if that ultra performance suspension is not tuned correctly, you'll have worse performance than the stock suspension and could very well cause a deadly accident. Slapping on a performance suspension will not make up for limitations in other parts of the car and if not tuned right, it can cause major stability problems.

[trodas]

SPL15 - first - thanks for very very informative posts there, and keep them up. I have only one correction. When you elaborated the chils heating-up, you mentioned that the heat is generated by the resistance and impedance thing. There is also 3rd factor, and that is the magnetic resistance of the used material - versus used frequency. It could not be underestiminated, because these coils heat up to about 60-70C pretty fast after start, so... BTW, most of the ferite materials have the peak performance (minimal amount of energy need to flip the magnetic field) at around 100C, witch is very bad for the mobo components (mainly caps) anyway :lol: The magnetic resistance rised over 100C relatively very quickly, so that is why they are designed to run at about 60-75C in most cases. When mine hit 126C, I know that there is something very very bad :(
But after all, this just support your warnings about number of heat dissipiated out there :)

Second:

Capacitors are not magic band-aids that fix limitations in your system.

This should be carve to rock and people should be slaped with this rock frequently. Including myself.

After years of OC and heavy HW modding, I lost only there components. Epox 8RDA+, eVGA FX5700U and DFI LP B. All there was lost by trying to do capacitor mod in order to enhance the voltage regulator performance (Epox, eVGA) or decrease the produced heat out of the mosfets...
All there attempts failed. Except eVGA, witch refuse to even start, after adding two caps on the Vgpu rail in order to ease the voltage regulator suppliing 1.5Vgpu for 610Mhz, the two mobos worked. Epox for 20minutes and DFI LP B for about 6 hours. Then both died.

I will try to resuscitate them, tough, but the chances are IMHO slim.

I just learned the hard way, that the discharging speed/power of capacitor is the most important thing ever and adding normal quality caps will kill the board almost instantly... :(
I can't buy low ESR caps out there (Czech republic), so Im restricted to what I can get from other dead mobos.

Thanks to SPL15 is also for explaining the coils problem, and why just replacing the coil used on mobo with other, similary looking one with more threads is far from wise thing. Increasing impedance should provide better spikes filtering (the coild on DFI LP B has very few treads - only 5 (!), while old ECS K7S5A (also AXP mobo, SiS 735 chipset) got coils with 10 threads) - but it, of course, also decrease the frequency of the pulses, witch might do more harm that good... :(
And it sounds as such nice idea, to just replace these coils! Even in the docs for the mosfets are mentioned that increasing the impedance in the LC filer part could reduce the mosfets temp up to 30%! ...however this is probably valid only for systems with stable current requirments, witch CPU's simply are not :stick:

[the phantom]

Hi SPL15,

I'm curious as to the mobo 'Never before Seen Mods/Tweaks that you speak of. Care to give a hint on what you have done or tried to achieve.

In my opinion, highly technical information is exactly what I want from forums, and what I find most useful. There is waaaay too much mumbo jumbo out there, and a distinct lack of high quality and qualified information, particularly for mobo mods. People scared away by things they dont understand perhaps shouldn't be dabbling in these areas in the first place. Hence I appreciate you input thus far....

Its also interesting how you seem to differ in opinion to pretty much everything suggested by Hipro5 in 'the great IC7 mobo mod' thread, i.e cap/inductor mods. You both exceed my knowledge in these areas so its not appropriate for me to make detailed technical comments, I am more interested in what your opinion of that is, considering the speeds he has attained.

[SPL15]

Hi SPL15,

I'm curious as to the mobo 'Never before Seen Mods/Tweaks that you speak of. Care to give a hint on what you have done or tried to achieve.

In my opinion, highly technical information is exactly what I want from forums, and what I find most useful. There is waaaay too much mumbo jumbo out there, and a distinct lack of high quality and qualified information, particularly for mobo mods. People scared away by things they dont understand perhaps shouldn't be dabbling in these areas in the first place. Hence I appreciate you input thus far....

Its also interesting how you seem to differ in opinion to pretty much everything suggested by Hipro5 in 'the great IC7 mobo mod' thread, i.e cap/inductor mods. You both exceed my knowledge in these areas so its not appropriate for me to make detailed technical comments, I am more interested in what your opinion of that is, considering the speeds he has attained.


My mods on my P4C800e-dlx so far are invisible and look 100% stock. I've got the Vdimm and Vdroop mods, but instead of grafting on some wires and pots onto my motherboard, I've replaced the resistors that control these things in the first place and added common sense design ideas to it. The Voltage that comes out of the DC-DC converter is created by a Voltage divider, I've stabilized the voltage divider with small tantulum caps in order to reduce spurous noise transients and voltage sags. But again you cant even tell its there, unless you have another stock P4C800e-dlx to compare it with and a good pair of eyes. I've added caps where they are missing in stock locations, I've rewound the Inductors on the DC-DC converters for the CPU and for the 4pin 12V input line. There are 5 places where ASUS decided they should leave the surface mount tantalum caps out so I added them there. I've added better quality capacitance in places that had just an electrolytic cap. I've basicly refined what ASUS already did, or did cheaply, or decided not to do. There are still many areas where I could do a mod, but it's not worth the hassle anymore on this old platform. There are spaces on the backside of the motherboard for MORE mosfets to help with the CPU Vcore that no one has said anything about....

If you look at Hipro's systems, he uses major voltmods to achieve his great results. Cap and inductor mods dont gain you the kind of results like Vmodding does. The cap mod for the IC7 that puts the cap right at the Northbridge could be LOTS more effective by simply using tantalum caps.

The things I say about electronics I didnt conjecture and didnt discover, the laws of physics determine what I say to be true. The issue's I've brought up on this thread and other threads are very well documented throughout the industry and have proven to be true in application and in theory. These are not new concepts by any way shape or form. Understanding electronics has many depths of knowledge levels. Lots of Engineers can do the "Programming" or design of a circuit, lots less understand the real world component interactions, tolerances, functions, limitations within the actual real world circuit. I've designed amplifiers where just by switching to a tantalum cap in the input stage reduced high frequency distortion at 25Khz by a magnitude of 10000%. They are the same capacitance wise, but FAR different regarding the "other" parameters ignored/not understood by lots of engineers and most design programs. ESR with caps matters depending on application, It takes lots of thorough understanding to know why ESR matters in one situation while raw capacitance matters in another.

OK I'm done for now, it's late and I'm about to get a good long...... foot massage :D .

[Kunaak]

I have to say, this has been one of the Most Useful posts I have ever read. in the last hour I think I learned more about caps, then I ever have in any other single post.

this area isn't my area to make stickies, but I think this post definatly deserves to be a sticky, cause theres alot of great information and very informed people in this post.

[TheBlackTulip]

Since I have a lot of power drops in my house, what about adding two 200v 1000uf caps to the main driving circuit of the psu + the original 200v 470uf I've got :confused:

I don't want it to improve anything but the tolerance to power drops...

Another trick I've been using is to put diodes on the 5v and 12v lines then combined choke from an old psu.
Then adding 2200uf 10v cap on the 5v and 3000uf 16v on the 12v.
It protects my hard drives from experiencing any power drains due to swapping some 160GB swappable SCSI drives I have.

i managed afterwards to shortcut 3.5 fuse on another line without any voltage drops in my hard drive lines :toast:

[SPL15]

Since I have a lot of power drops in my house, what about adding two 200v 1000uf caps to the main driving circuit of the psu + the original 200v 470uf I've got :confused:

I don't want it to improve anything but the tolerance to power drops...

Another trick I've been using is to put diodes on the 5v and 12v lines then combined choke from an old psu.
Then adding 2200uf 10v cap on the 5v and 3000uf 16v on the 12v.
It protects my hard drives from experiencing any power drains due to swapping some 160GB swappable SCSI drives I have.

i managed afterwards to shortcut 3.5 fuse on another line without any voltage drops in my hard drive lines :toast:


It wont do much of anything for that situation. Caps are not batteries. 2470uF is a peasely amount of capacitance for power backup. LOTS LOTS more would be needed to make any difference for a power drop out situation while the PSU is under load. I have an amplifier with 1 Farad of capacitance (that's 1,000,000uF) and if there is any load on the amp, it will discharge to an unacceptable level within milliseconds if I shut off the power. Adding caps in your situation would make the mains input rectifier diodes work much much harder and will create a much larger charging current transient which creates a tremendous amount of RFI and EMI which is just plain not good when dealing with high clock frequency digital devices. The only thing adding these caps will do is make your standby 5 volts voltage last a second or two longer when you disconnect the plug with the PSU off. In the worst case, you'll blow the rectifier diodes or you'll get electrocuted by the added capacitance if you ever decide to open the PSU after it was just plugged in.

What you need is a good UPS (Uninterruptible Power Supply) I recommend a higher quality unit that converts the 120/220 VAC into 12/18/24 DC volts and then converts the 12/18/24 volts back to 120/220VAC. This type isolates the load from the main's circuit and the output of the unit is 100% unconditional to the 120/220VAC input. This type filters out any and all harmonics, frequency deviation, spikes, sags, etc. The cheaper ones (That 99.9% of consumers have) connect the 120/220VAC directly to the outputs until it senses bad voltage. This type uses passive filtering (Maybe) and has a wide acceptable voltage variation (90-135vac TYPICAL). Also, the cheapers ones have no frequency variation protection. But in reality, any decent quality UPS is better than none. Especially if your in an area or country with crappy power.

In your filter that you described above, eliminating the Diode will not hurt the LC filter. The diode is taking probably .7 to 1.4 volts away from the rail voltage. If you are using low voltage schottky or germainium Diodes, you may be getting only a .3 volts of drop, but still not exactly good. The Diode on you configuration with that amount of capacitance with a series inductor isnt doing anything helpful, but it IS dropping voltage. Unless your overvolting to compensate for the Diode drop, I'd get rid of them. If you trying to use the diodes to limit voltage spikes from removing the Hard Drives, you'd be better off using transorbs (Transient voltege suppressors) across the lines. a 15 volt 600watt unidirectional transorb across the line (Reverse bias) would solve voltage spike issues, and is what I use personally on lots of electronics i build.

[TheBlackTulip]

i noticed that the voltage is 11.86 and 5.02 which is not that bad...
i used diodes from psu

[SPL15]

Are those readings before or after the diodes?

If your using diodes from a PSU, they are just regular silicon diodes which will have about a .6 to 1.4 volt drop across them. Also, depending on what diodes your using, the current through them may be excessive which will short them out in little time. If your running multiple Hard Drives, your going to need a large TO-220 or TO-245 package with a small heatsink in order to dissipate the heat. Also, start-up current is high with hard drives.

If you are getting small voltage drops across the diodes or no voltage drop at all, your diodes are shorted. I would check them out, and probably just get rid of them as they are doing anything much for noise/voltage spike supression.

This is all assuming that the diodes are in series with the load. How do you have them configured?

[TheBlackTulip]

(the voltage readings is after the diodes..)

i used fast respond diodes which is Ge made of (those small gray ones with Cu heatsink installed)
they were on main lines of 5 and 12 volts from old dvd psu which is 5v -5A and 12v - 4A written on
i think it shold be more then enough
they isolate the hard drives line from drain cuased externally loading on of the line (like blowing 3.5A fuse or connecting large scsi drive)
as i said they do the trick so i dont have drains any more and the drives arent effected any more...

what about adding the choke on the scsi line - then power drain will be limitted to some delta since a choke is just another word for inductor right???...

they are like this

in--5vLine---|>--cap+---out
GND-------------cap----out

[[XC] moddolicous]

Holy thread resurrection. Finally got interested into doing something to my motherboard, and this looks like the perfect thing. Could I use this type of capacitor: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=333150&e_categoryid=380&e_pcodeid=01420
in parallel (cause hellfire said parallel>single big one) with other caps by the cpu??

[Revage]

any capacitior mods for dfi nf4 ?

[stealth17]

any capacitior mods for dfi nf4 ?

Ditto x1000!!!

[Big Pope]

Oh, i missed this thread last year. I will supply good quality ultra low ESR caps for this project if i know this thread last year.:cool:

[Soker]

sexy core ;)

[stealth17]

Where can I get Ultra Low ESR caps from a known reputable source? I am looking for Rubycon or Sanyo if possible.

[Big Pope]

Where can I get Ultra Low ESR caps from a known reputable source? I am looking for Rubycon or Sanyo if possible.

If you need ultra low ESR with performance and quality, then i supply you. However, I can't help you if you need "brand name". Try to search "Samxon" or "Big Pope" in google, you can got more details.