I GUARANTEE 3.7gHz and ddr501

[charlie]

if SOMEONE will help me with this vcore mod and/or vdimm mod on my Albatron PX845PEV Pro mobo. I've posted this all before at
"And this brick wall won't budge" thread...
I'll try one last time>>>>
here's the mobo

[charlie]

oK,
I've done more research and here's what I've got for ya'
Looking at the above pic's,
here's #1 Fairchild P21sd, 74vhc74

what's this???? needed for a mod??

[charlie]

And here's #2
RT9174


am i getting warm?
C

[charlie]

And here's #3



Any better???
DDTUNG, HELP!!!!!!!!!!!!!!!!!!!!!!

[KS1]

i don't know if you've read "vmod basic" in this forum or not.
if not , pls do so.

- a Vcore regulator IC should have pin Vid0, Vid1, Vid2, Vid3, Vid4 on it to determine the volt output.

- a Vdimm regulator IC should be near the DIMM slot (yours number 2 or 3). To identify the IC, You got to check by adjusting Vddr in BIOS and see the which MOSFET output is affected.

- try also looking for Gigabyte m/b mod since I heard that Gigabyte is a close friend of Albatron.

[charlie]

KS1,
Thanks, that helps. I'll start a little more study.
C

[charlie]

OK,
So IC #3 the APL 1581 seems like it may be the vcore regulator.
However it's nowhere near the cpu. It is described as

[charlie]

And here's the schematic>>
what next?

[KS1]

i am not sure if number 3 is a Vcore regulator.

you can check this by changing Vagp in BIOS and use a dmm to check at Vout pin to see if it changes accordingly. then change Vddr and recheck the Vout again. then change Vcore and recheck again.

RT9174 looks more likely be Vagp volt regulator. pls check.

don't hurry. this thing takes time.

[KS1]

this is an example of Vcore volt reg.
you can see 5 Vid pins where the arrow is pointing at.
http://home.wanadoo.nl/krairach/krairach/voltreg.JPG

[charlie]

Ahhhhh....
I think I may have seen that one, let me check my files...
BTW with your help, IC#3 has output pin voltage of 2.53v default,
and with my BIOS vdimm set to 2.8v
VOILA! 2.85v on multimeter!!!!!!!!!!!!!!!!!!!!!!!!!!!!
from output pin on 5 pin apl1581!!!!!!!!!!!
Am I onto something???????
What next????????
C

[KS1]

triple check with different Vddr setttings while keeping other parameters constant.
you must be absolutely sure before going on.

then study the datasheet unitl you fully understand what you are going to do especially on the Vout setting part (resistor divider circuit). this is at your own risk so be absolutely careful.

hint: use a 1.5V battery. get 2 100 ohm resistors (R1 and R2). connect R1 and R2 into a resistor divider circuit. see what volt you got.
then change R1 to another value eg. 500 ohm. check what volt you got.
then change R2 to another value eg. 500 ohm. check what volt you got.
then change R1 to a 1K ohm Variable resistor--starting from 0 ohm, check what volt you got. slowly increase the value of resistance while keep your eyes on the multimeter reading.

play around with this testing circuit until you are comfortable to go ahead.

[charlie]

ok,
maybe I'm a bit dense here...
what exactly will I do to increase the voltage? Add a variable resistor or set resistor to what?
Here's the schematic again. The only mod I've done is the Radeon 9700 vcore/mem mods...So i am a noob:)
And yes, with bios vdimm adjustment, reading pin 3 on apl1581 changes, 2.6v>>2.61v 2.7v>>2.73v 2.8v>>2.85v
C

[Holst]

Can you take a close up pic of the chip.

Once you find the AJD pin poke the board and find resistors on the board connected to it. then by dropping the resistance of R2 you will increase the Vdimm (I think)

[charlie]

Holst,
ADJ pin is pin #2. here...
NOw once I identify this circuit, where and how do I drop the resistance? Do I cut a leg off of the mobo and run a fixed resistor?
How? Add a resistor? Hmmm........
I apologize to all of you that are trying to help me. This is a new part of the hobby for me, but it sure means a lot!! Xtreme Systems.org...best forum around!
C

[charlie]

and here

[PiLsY]

Looking into it now.

Give me an hour or so.

PiLsY.

[PiLsY]

Or even 10 minutes......

You could adjust R2 but tbh itd be easier to adjust R1.

Stick a 47k pot (preferably a 22 turn one so you get a lot of adjustment) between pin 1 and pin 2. Start off at max resistance and dial down slowly.

Looking at R1 and R2 each being 125ohms my suspicion is youll end up using a 1K pot to adjust it, but better off safe than sorry.

One thing to be sure of - have you checked the vOUT and made sure its equal to whatever vdimm you have set? The vreg is only specced up to 2.55v, and im assuming your board allows more than this via adjustment. Its unusual to see a manufacturer go that far out of spec on these.

That vreg would be far better suited to adjusting VAGP or VDD(chipset) than VDDR.

With it only being specced to 2.55v I would play it safe and stick a heatsink on it (itll probably be getting quite warm as it is if its supplying over 2.55v). I really wouldnt take your vdimm too far in case the thing blows (assuming it does control vdimm).

PiLsY.

[charlie]

Pilsy or as I will now call you, Saint Pilsy ;)
All you guys...super.
Yep I triple checked it, pin 3 on apl 1581 >>
BIOS 2.5v
MM 2.53v
BIOS2.6v
MM 2.65v
BIOS2.7v
MM 2.72v
BIOS2.8v
MM 2.85v
So it's for sure. So tommorrow, I need to pick up that 47k pot and solder it in BETWEEN the pins #1 and #2 as per above diagram?
Nothing else...just solder the pot, adjusted to max resistance with my multimeter, across the 2 pins (1 and 2) and test away...right? Nothing goes to ground...just do it as described?
And as per Vcore mod should I just forget about it as I can get 1.79-1.80v (BIOS 1.85v) now? I've got this great 2.66 that runs cool and hard 182fsb max (ddr480+) on air. I'd like to punch it up, is it worth the risk?
Thanks again!
EDIT! 4.7k ohm or 47k ohm? like this?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F003%5F006%5F010&product%5Fid=271%2D281
or like this?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F003%5F006%5F003&product%5Fid=271%2D342
what do you do with third leg of pot?
C

[PiLsY]

You connect one pin to the middle leg of the pot, then the other pin to either the left or right pin. Whichever leg you connect it to governs which way you turn the pot to raise or lower resistance - thats all :).

What id do is solder 2 long wires to the relevant pins, then solder the pot in place. When you figure out what resistance youre looking at running then swap the 47k pot for one better suited. For instnace, if you get all the way down to 1k or so resistance (thats half a turn on a 22turn pot from the end) then stop. Swap the 47k for a 1kohm pot and start again on max resistance on that. You need to be careful that you dont turn the resistance down too quickly.

Id say buy a selection of pots from 47kohm down.

That pot youre looking at is no good - its only a single turn. Radioshack isnt the best place to go for them tbh, they dont have many at all.

If youre willing to take a small risk by starting off at 10k (im 99.9% it should be ok) then get this one http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F003%5F006%5F003&product%5Fid=271%2D343. I would also get this one http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F003%5F006%5F003&product%5Fid=271%2D342 as i suspect that will be better suited.

Go into bios and change your fsb to 133, mem divider to 1:1 and set your ddr voltage to minimum. Adjust both pots to max resistance. Solder 2 wires to the appropriate pins. Solder the 10k pot to your 2 wires coming off the pins. Boot the board up into bios and very slowly turn the resistance down while watching your vdimm in the pchealth screen (I assume it shows vdimm). Its a 15 turn pot, so count each turn. Each turn drops resistance by 0.667Kohm. If you get to 13 1/2 turns and nothing happens then switch off and remove the 10k pot. Put the 1k pot in at max resistance (remember the relevance of which legs you connect to whether its at max or min resistance) and slowly start crankling that down.

If you want to get advanced you can always run both pots at once. If you find the 10k pot adjusts the voltage but in quite big steps then all you need to do is solder the 1k pot inline with it, set the 1k to max resistance and give the 10k pot one more full turn. You can then "fine tune" with the 1k pot.

PiLsY.

[EDIT] Nearly forgot my disclaimer - if it breaks it aint my fault :). Just go nice and slow and dont hold the soldering iron onto the vreg for too long and you should be ok. Remember to check what temp that vreg gets up to with it set at 2.8v in bios before you do any mods. If its warm already theres a possibility it could burn out at higher volts. Get a heatsink on it if its running hot.

[KS1]

be careful boy. i don't recommend you go ahead until you fully understand what you are doing.

perhaps if you don't know what i am trying to do:
i am trying to train you how to catch a fish so next time you could go fishing by yourself. but it's up to you.

[charlie]

I'm going to take the day to think and absorb this stuff and play with some resistors and read the spec sheet and go from there.
Thanks.
C

[KS1]

when you think you are confident to do the mod, the last exercise is to connect a 1K ohm variable resistor in pararell to R2 of the testing circuit. set the VR to 1KOhm, keep your eyes on a DMM and slowly decrease the resistance value, see the result.
this is what you will have to do to the actual circuit.



+ ----|---- R1 ----|---- R2 ----|--- GND


- before moding, check if a resistor divider circuit is present as in the diagram above. if possible, check for the value of the resistors too and see if it corresponds to the diagram or not.
- if R1 and R2 resistors in the diagram are both a 125 ohm resistor, work out the formular in the diagram to come up with what R2 value is needed to get the Vout you want (roughly). That should determine a rough value of R2 (called it Rt).
- then you need to work out how to make R2 value becomes Rt value by solving this equation to find VR: Rt = R2xVR/(R2+VR)
- The result (VR) should tell you roughly what VR value you should use ie. if it's 800 ohm, you should uses 1K ohm VR and start from 1K ohm
- final work is to solder a VR in pararell to R2.

good luck modding

[charlie]

KS1,
Yes, I'll play with the test circuit (1.v battery and fixed resistors) until I understand it perfectly. Good idea! Thanks.
C

[charlie]

Saint Pilsy and KS1,

The VMem Mod was a complete SUCCESS
:toast: :banana:

I installed a 50K - 20 turn potentiometer set to max (50k) and at about 19 turns...the multimeter went
2.53, 2.57, 2.59...until I stopped it at 3.0v
I haven't put on the 10k component yet, or the 1K, I may leave it like this, as it appears I have a bit of adjustability.

However, my gain is nill at this point. My board has never liked cas2, 6,2,2 and it still doesnt'. Even at 3.0v vdimm, it'll go about 150 fsb or so and give me a NASTY black screen exception error notice. So, where I MAY gain something is at the top end. I'll try 183+ fsb (cas2, 6,3,3) and if my cpu can hack it, we'll see what the RAM can do! Now I'm waiting for the room to coool off. It's not a very cool night, tonight.
C

[KS1]

good work!

try using 2.5-3-3-7-2

do you think you can do Vagp, Vio, and Vcore mod?

the basic principle is to make FB pin thought that Vout is too low.
if you can't find FB, Vsense is to look for. if you find Vsense connect to Vout directly, it is a more difficult mod (see how Jeff mod Vddr on 8RDA+ in this forum)

[SBeaver]

Couldn't find an electronics store that was open today so I will try this myself on my PX845PEV on monday if all goes well.

[Clevor]

Could you guys post photos of exactly what chip to mod and what pins to attach the leads of the pot to? I got a couple of 10k (and I think 47k?) pots but I never got around to doing this on the Athlon boards.

Yeah, I notice the PX845PEV PRO doesn't like 2-2-2-6. I can do DDR426, 2-2-2-5, then maybe DDR434, 2-2-2-6, then have to use 2-3-2-6 from DDR434 to 466.

I've gotten a TwinMOS 5-ns Winbond stick to DDR461, 2-3-2-6, and Corsair XMS3500 C2 to DDR466, 2-3-2-6, but can't go higher with either stick stuck at 2.8 volts. Same # of errors no matter how relaxed the settings.

Interestingly, I recently picked up a used XMS3500 C2 stick in Japan and this one does DDR450, 2-2-2-5! But it will not go any further like the other sticks. So I need more than 2.8 VDIMM.

[charlie]

clevor,
on the first page of post, we detail the mod and chips...vr between pins 1 and 2, set to 50k at first, adjust down as you watch multimeter. Solder neatly as the pins are pretty small.
C

[Clevor]

Charlie, there are pics of two chips, one is long and rectangular and has pins on each side while the other is small and square and has 5 pins on one side only (looks like a MOSFET). Which chip do you mean?

[charlie]

Yes, the one with 5 pins on the same side. Study the schematic and proceed with caution
C

[leinad78]

so, can´t see pictures :-(

wheres the problem exactly?

DF