Antec TruePower 550 PSU Volt mods ? ~ PART II ~

[StinkN1]

I now have some knowledge of modding this PSU , but would like to know if anyone really "knows their math" ?? ESPECIALLY ~ Hëll ‡ Fîrë / pc ice and STEvil !!! you 3 know it all !
I have this so far right ?
3.3v = 10ohm resistor + 1k vr (or 20k VR alone)
5v = 36Ohm + 10k VR
12v = 68 Ohm + 10k VR
The BIG question I have is - If you can use a 20k trimpot alone for the 3.3v sense line , would I be able to use trimpots alone for the 12v and 5v lines safely ? 50k or 100k for 5v ?? 100 or 500k for 12v ?? Also - is using the resistor + a VR safer ? Does the resistor act as a fuse ? Also are the resistors I listed supposed to be ohm or k-ohms ? I would rather go the trim-pot by itself route as it seems like less work than grounding it out and such , but I want to do it only if it is just as safe as the resistor+VR method .Lemme know please
Thanx guys :toast:

[StinkN1]

: Update : So far from what I have been told it is somewhat of a neccessity to use resistors as using Vr trimmers alone can result in voltage fluctutations ..
The problem is where in the world do I ground three seperate rated VR resistors ? Can I run them all to the same place ? Would tapping into a ground on the psu be wise ?
I kind of though that each line had it's own ground - rated to a certain spec .. Each molex has it's own black wire(s) and the ATX connector has 7-8 black wires ; so which one would I route my ground(s) into safely without throwing everything off ?

[sjohnson]

My first thoughts:

Does the Antec TP 550 have sense lines for 5v and 12v in addition to the sense line for the 3.3v rail? Most PSU's have only the 3.3 sense line, if they have any at all.

Those PSU's where I've modded the 5v rail have required modding the PSU circuit board - not something I'd recommend to anyone without high-voltage circuit experience. A small risk but a possibly deadly one.

Another question - are you sure that the 12v and 5v rails are seperate on that Antec? Many PSU's have the 12v and 5v rails generated from the same circuits. So, modding the 5v also mods the 12v.

Some PSU's with the 3.3 sense line won't "take" without the fixed resistor. Although I have modded both an Enermax and an Enhance with just the VR, no problems with stability after almost two years.

[StinkN1]

Yes , it has sense lines for all three .. Yellow w/sense is 12v .. red w/sense is 5v and orange w/sense is 3.3v !!
I am not 100 % sure that the lines are "seperate" but they do have seperate sense lines ! So I guess they are ; yes !
What about all the lines using only a VR ?
Glad you could make it to my thread !!

[sjohnson]

Like I said, some PSU's won't work without the inline fixed resistor. Only way to know for sure is to try it.

The grounds for the three variable resistors can be shared.

Do you have a link to any 5v/12v mods for the Antec, for me to study? I'm coming up with pretty much nothing on a google.

[StinkN1]

No - no links at all .. I will take a pic of the ATX connector tomorrow if you like ? Will it help at all ? I am 99% sure it is the same as an antec TruePower 430/480 ..

[Malves]

Antec True Power models have 3 individual dedicated circuits.

[sjohnson]

No, I just wonder about the range needed for the VR's.

Use of multi-turn cermet VR's is a MUST IMO. The lowest ohm VR that is larger than the largest needed resistance is best, that way you have more fine control over the voltage, plus you adjust it slowly - that's safest for the PSU and board.

[StinkN1]

ok - now you have definately lost me sj .. "The lowest ohm VR that is larger than the largest needed resistance is best" ?? Come again please .

[StinkN1]

Also - I am going to use the last ones down on this page http://www.oselectronics.com/ose_p75.htm 15 TURN 3/4" RECTANGULAR CERMET TRIMMER
Tolerance: ± 10%
Power rating: 0.75W
Maximum voltage: 300V

[sjohnson]

OK, an explanation:

Assume you need 8.9K Ohm resistance for a zero-volt change and 8.0 K Ohm to get your 3.3v rail up to 3.6 - your targeted max.

8.9K Ohm is the highest resistance you want, so an 8.9K Ohm cermet would be ideal. 10K Ohm is available as is 20K Ohm, but you want the 10K. 10K is closer to the 8.9K you want than 20K.

Clear? :)

[StinkN1]

I get it now , but as I said I was going to use either resistors+VR , but wanted to use vr's alone so save trouble grounding them all .. I suppose I just am going to have to do it Malves' way .. He has a truePower ..
The only reason I really want to mod all three is I read that if you do the 3.3v alone , other lines get lots lof fluxtuations if you go over 3.4v .. I would have it at 3.45-3.50 because the new motherboard I have coming is known to drop .2v on the 3.3 when under stress ..
If I do one line - might as well do um all ey ?

[sjohnson]

u sed it ;)

[StinkN1]

sjohnson r u trying to sike me out ..

[sjohnson]

might as well do um all ey - just agreeing with you

[StinkN1]

so are my resistor and VR calculations ok ? 1/2 watt resistors + 3/4 watt vr's will not conflict with each other ?

[sjohnson]

That's OK - the sense lines use less than 1/2 watt and mixing wattages has no affect.

[StinkN1]

Okay .. Im trying to get technical as to make sure all will go well !! You guys have been helpful !! Still waiting for hell fire to get off the squatter and come on in though !!
Thanx fellas !! Any other comments or findings please lemme know !!

[Hell-Fire]

Hello guys. ;D

I highly recommend using the Cermet vs the Trimpot. The trims are a less fine tuning vr. Go with the Multi-Turn Cermet VRs (usually 15 turn if memory serves).

You dont have to use an inline fixed resistor with the vr for all power supplies, but you do have to use it for some.

No, the fixed resistor does not act as a fuse. Basically it just gives you a starting point to go from.

Doesnt truly matter which vr you use. Whether it be 10k or 20k, as they all go from 0 resistence to the max setting.....only difference is when you get into situations where you need a high base resistence to start with...say when modding certain north bridges...but thats another story. Some people use the 1k vr's on the 3.3v rail, but you have to be very careful when adjusting those as each turn means more voltage vs per turn on the 10/20k vr's.

For the rails on my Antec TP550, I used 3 47ohm fixed, and 3 Cermet Multi-Turn 10k VRs.

I know that pc ice used a vr straight inline after making his cut on the sense lines...I cant recall what psu that he was working with at the time, but every psu I have modded (4 Antec's and 3 Enermax) have all required the use of a fixed + vr scenario.

Mixing wattages wont matter in the least.

[StinkN1]

Great ! Thanx !! I was hoping someone would say no need for resistors + the VR , but seeing as how I can ground it right into my ground wire on the PSU , it's just as easy !!
Will post back how it went .. !!
Whats a trimpot ?? These are cermets right >> ?? http://www.circuitspecialists.com/level.itml/icOid/6955
and
http://www.circuitspecialists.com/level.itml/icOid/6945
Any difference between the two ?

[Hell-Fire]

Originally posted by StinkN1
Great ! Thanx !! I was hoping someone would say no need for resistors + the VR , but seeing as how I can ground it right into my ground wire on the PSU , it's just as easy !!
Will post back how it went .. !!
Whats a trimpot ?? These are cermets right >> ?? http://www.circuitspecialists.com/level.itml/icOid/6955
and
http://www.circuitspecialists.com/level.itml/icOid/6945
Any difference between the two ?

Not really, they look exactlly alike to me...except for the size, but that could be just that the pic is distorted on the one page which makes it look smaller. Either would do. I get most of my mod stuff at Radio Shack if possible versus buying off the web. Nothing sucks more than paying more in shipping than the product is worth.

This is how you want to do it if you are using the fixed + vr:

http://www4.ncsu.edu/~rwbradl2/CSC251/images/3.3rail Vmod.jpg

I soldered an old molex connector from a dead psu to the ground wire of the VR and then plugged that into a live molex from the TP550. A simple way to be able to disconnect the vmod versus soldering a ground somewhere so that its a permanent thing unless you desolder it.

As far as what a "Trim Pot" is, it depends on who you ask actually. Some people call the Taper Potentiometer a trim pot, when truly the Cermets are actually Trimmers in the truest sense. To put things straight, a Cermet VR is a Trimmer (Trim Pot), and a Taper Pot is just what it says it is....but they are both VR's of course. Here is a Taper Pot, which is what I was referring to about not being as fine a tuning VR as a Cermet VR, but there are instances where using a Taper is needed. The taper also has the problem of being a much larger vr which means using them in small areas isnt possible. In that case you can use other resistors/vr's/cermets in a series.

http://www.radioshack.com/images/ProductCatalog/ProductImage/271/271-092.jpg

[StinkN1]

does it make any difference at all if I put the resistor and vr closer to the atx plug or closer to the psu itself ? Also one more thing . whats the difference between metal film and carbon film 1/2 watt resistors please ? :rolleyes:

[StinkN1]

Another idea >> http://directron.com/atxextension.html
Catch my drift ?? Nothing permanent .. It would work right fellas ?

[Hell-Fire]

I wouldnt recommend using that extender unless all your wires matched up with those wires...as in sense lines, etc. If it does then it may be a good idea to try mods on it. If it works...then simply removing it clears the mods and obviously saves your warranty.

It doesnt matter where you put the resistor/vr on the cable bundle. All my latest ones have been done inside the psu housing.

[StinkN1]

If i use the extender , I wouldnt need to use sense lines though .. Would I ?

[Hell-Fire]

Using an extender is just like if you snipped all hte wires and sodlered longer wires to it. The extender does what it is suppose to do...make your ATX cable longer in instances where it doesnt reach for whatever reason from the psu to the motherboard.

If you wanted higher rails on the psu, you would still need to modify the extender...which is the point I thought. You buy the extender, make sure it has all the wires your atx connector has, then mod the extender versus the cable bundle from your psu so that you do not kill the psu warranty.

[MentholMoose]

Modding an extender won't work because the sense lines connect to their corresponding rails at the ATX connector, so there is no reason to have the extra sense wire on the extender (it wouldn't make sense). If the extender for some reason did have extra sense wires, they would be non-functional as sense wires and connecting them to ground would be 'bad' (same effect as connecting the rail to ground).

[sjohnson]

MentholMoose is right, any sense wires on an extender would NOT have a distinct path back to the circuit board on the PSU, grounding sense wires on an extender would be also grounding the rail - not good!

[Hell-Fire]

Ahhh, hadn't thought about that aspect.

Thats what happens when you are typing at 4am....only one part of my body works after 3am and its usually my fingers, not my brain.

What happens if you ground Hell-Fire with the other end of a Sam Adams? A tired, blurry eyed modder.

[StinkN1]

See I was thinking more along the lines of since all the sense wires trminate at the same point , maybe it would work , but then again the wires in the ATX extender will actually have power running thru them and as Menthol said also - the sense lines are actually running to the PSU .. Oh well , was just a thought ..
MY THREAD IS 2 PAGES LONG !! Yippee..

[Hell-Fire]

I am in the process of remodding my TP550 and can pot pics here if you want them added to your thread StinkN1. =)

Had to rip my rig apart so I could mount my new water/tec system into it...figured I would remod my psu while I waited on a few parts to get here from Swifty/2CoolTek/Cooltechnica.

MentholMoose's "moose" has 2 mouths....lol. And who said radiation and a hole in the ozone was bad for anyone. :hehe:

[StinkN1]

Yes Hell fire ! Post pics and enhance my oh so plain thread !! please grace it with your photage !!
Thanx !

[Hell-Fire]

Originally posted by StinkN1
Yes Hell fire ! Post pics and enhance my oh so plain thread !! please grace it with your photage !!
Thanx !

LOL!

Please dont start sacrificing cows and pigs just yet. I only learned what I am sharing here from other modders here at the wonderful land called XtremeSystems...and I have lots more to learn.

Of course I will post pics.

[StinkN1]

Originally posted by Hëll ‡ Fîrë
Of course I will post pics. :worship:

[StinkN1]

:banana3: :banana: :YIPPIE: :banana: :bananal: :owned: :sick: :devil: :shrug: :ROTF:

[STEvil]

You can ground the trimmers to a common ground (the same point).

At least now I know XS isnt sending me emails when i get a PM anymore.. :smileysex

[Marvin]

Originally posted by Malves
Antec True Power models have 3 individual dedicated circuits.
Malves, sorry the off topic, but the woman in your logo is Malu Mader, isn´t it ?
She is wonderful:D

[Tum0r]

I have tried it with my tp380w and it worked.
I'm currently running 3.45 ,5.3 and 12.40 (shifts between 12.34-12.40 :( ) I just used 47 fixed with an 10K VR and the read outs where measured with an MM without the PSU being hooked up to the mobo.

Bios tells me 5.3 and 12.4 (cant see 3.3line current state dough)

I only have an Vcore of 1.675, this does however run @1.664-1.680...

My Vdimm always bin 2.82-2.83 and I was hoping after upping the 3.3rail I would get closer to 2.9 , and words on that? (and max 3.3 ?)

Only thing a regret is not making a way to readout the 3.3rail (while hooked up)

Before the mod I had these rails: 3.29, 5.10, 12.09
I doubt I'le get better fsb now (nanya pc2700 :sick: )

I guess there isn't a way around a Vdd mod (I'm getting some high end not for the nanya :) )

Forgot to mention I used an molex connector with only a ground and 12V wire for fan use as ground since I had no use for them

[STEvil]

stick a paperclip into the atx connector and hold it to the DMM tip to check the 3.3 rail.

[Tum0r]

Would it matter if u leave the hdd hooked up to the psu?
Don't think I'le be upping the 3.3 anymore as its already at ~3.5V It's on 3.63 :D (still that 2.82-.83 Vdimm is bugging me...

12 is running at 13.3V and 5@5.5 but
My radeon likes it
9800SE passes 3dmark with no artifacts 425/375 stock cooling and softmodded :YIPPIE:

I like this modding, next is my R9800Se and Vdimm :)
I'le practice on some old 486 hardware first :p:

[STEvil]

Yeah, radeons react well to high 5v lines.

2.82.2.83vdimm fluctuation is nothing. 2.72-2.83 would be, though.

[Tum0r]

Running 3.6 ;5.5 and 13V rails so thats kinda high...
Should I lover the values or is it ok?

Or is it ok to go higher or is it not worth it?

What would be the first thing to go (wrong)?
At what signs should I be looking for?

[STEvil]

Should be fine,

5.2/3.45/12.8 if you want to be safer.