Guide: Power Supply Sense Wire Modding

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11-22-2004, 06:39 PM
Hell-Fire

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Quote:

Originally Posted by moparacer

There is as good as I can get with my junk camera lol.
Cant see anything that looks like any pots to adjust. :(
Let me know if you need any close ups for certain areas and I
will see what I can do.

http://images5.theimagehosting.com/Cap0005.1.JPG

Whats the markings on the chip to the top left under the fan plug?

Also, be sure to look carefully for smaller VRs. People make the mistake in looking for the standard rectanlge blue VRs, when a majority of the time if its a factory pot it is soldered to the pcb and is a single turn VR with a phillips head adjustment cap.

Identify the 2 things I pointed. The one thing I pointed to with an arrow might be nothing, but cant tell so thought I would ask cause it looks suspiciously like a single turn VR.
11-23-2004, 07:58 AM
moparacer

The one you drawed a arrow to is a small capacitor and the one you circled has no adjustments and is is marked IC202 on the board but I cant make out the part number on it. If we cant come up with anything I might just bite the bullet and order a new PS with adjustable rails. Which do you recommend?
11-27-2004, 08:42 AM
Mussels

hello from a newly registered member.

doing this mod, and am semi-experienced in electronics, but have hit a brick wall modding the 12V line on my antec trueblue 480.

40ohm resistor, two 5K VR in series to make 10K total, and it refuses to budge the 12V.

the only thing that i have done different, is my VR is soldered on the ATX plug end of things, and not the PSU side of the fixed resitor. could this have any effect?

yes the VR's work, yes its connected to earth properly, and yes im stumped on this one.

i'll check back here over the next few days, to see if anyone replies.
11-27-2004, 10:52 AM
Hell-Fire

Yes sir, that is the difference. The VR has to be on the opposing side of the fixed resistor.

Given that you indeed have the 2 5K VRs connected together properly, as soon as you redo that circuit with the VRs on the psu side of the fixed resistor, you will be able to adjust the 12v rail.
11-28-2004, 04:52 AM
Mussels

could this be why 1 in ten or so n00bs screw it up? doing the same thing as me?

and just so i know WHY, whats the technical reason that it doesnt work?
12-02-2004, 06:22 PM
THunDA

Well .. Ive been busy but I just wanted to post some pics of my sense mod..

With Hellfire's guide even I was able to do this..hehe..

http://img35.exs.cx/img35/1503/4d-psumod.th.jpg

http://img35.exs.cx/img35/9785/77-psudone.th.jpg

Thanks again HellFire.. :)
01-02-2005, 06:34 PM
nubian

i've done this mod with an antec true power 430.
it worked for a couple of months.
not my fans and power supply cooling fans are not working.
why would that be.
it still powers up and all but the fans do not work.
any ideas?
thanks in advance
01-03-2005, 02:22 PM
nubian

bump...anybody?
please?
01-03-2005, 09:01 PM
Hell-Fire

Take a look at the 12v rail and make certain it is powering.

Other than that, I would say the fans bit the dust.
01-04-2005, 01:40 AM
iddqd

Hey, Hell-Fire, I noticed you did the mod on an Antec PSU. I was going to throw mine away for a PCP&C510D, but now having second thoughts. First of all, what was the maximum 3.3 you could get out of that thing? Any way of making it go to at least 4.2V? How about a PCP&C? Or OCZ 520?

Quote:

Originally Posted by nubian

i've done this mod with an antec true power 430.
it worked for a couple of months.
not my fans and power supply cooling fans are not working.
why would that be.
it still powers up and all but the fans do not work.
any ideas?
thanks in advance

That is a common problem with Antec power supplies, I'm afraid. They used El Cheapo fan controllers, which all, inevitably fail (mine didn't work out of the box!). What you do, is get different fans and wire them directly to a 12V rail, to prevent any such failure.
01-04-2005, 02:01 PM
Hell-Fire

I dont recall how high it went, but fairly high. You can check the specs on the supply to find out the trip point for OVP.

I would get the OCZ supply before the PCP&C one. I had a PCP&C 510 Deluxe and it was awful. Fluxing rails under heavy load and high voltages. Not stable as the OCZ is.
01-04-2005, 07:21 PM
iddqd

Quote:

Originally Posted by Hell-Fire

I dont recall how high it went, but fairly high. You can check the specs on the supply to find out the trip point for OVP.

I would get the OCZ supply before the PCP&C one. I had a PCP&C 510 Deluxe and it was awful. Fluxing rails under heavy load and high voltages. Not stable as the OCZ is.

I thought the resistor was to trick the OVP? What components should I select in order to maximize 3.3 line adjustment (resistor, pot?) on the Antec?
01-04-2005, 08:19 PM
Hell-Fire

Quote:

Originally Posted by iddqd

I thought the resistor was to trick the OVP? What components should I select in order to maximize 3.3 line adjustment (resistor, pot?) on the Antec?

No sir.

The resistors are there to force the regulators on the pcb to force more current to the rails. OVP is handled seperate from these rails.

Try a 10ohm resistor and 1k vr.
01-05-2005, 10:10 AM
iddqd

Quote:

Originally Posted by Hell-Fire

No sir.

The resistors are there to force the regulators on the pcb to force more current to the rails. OVP is handled seperate from these rails.

Try a 10ohm resistor and 1k vr.

The PCB inside the power supply?

Ok a couple more things - is there any way to remove/trick OVP in the Antec? What's the maximum adjustment you can get on OCZ PS520 (such as wire something that runs at 3.3 to the detector, or put a resistor there)? OCZ says it's 3.6, is that due to the OVP they have? If so, is there any way to remove/trick the OVP on the OCZ?

Edit: I know there's a way to get rid of the OVP on PCP&C510D, but you're saying that's a bad PSU.. :confused:
01-09-2005, 02:56 AM
pleenmeel

2 Attachment(s)

Help with mu psu Qtechnology gold 400watt 12cm fan

Dear modguru (hell-fire)
First of , excuse me for my poor english (I'm from Holland)
I'm new to the forum and man am i glad there is such. I really need help here.

I've got an Qtechnology PSU Gold blue fan (QT03400G).
I've also got an Asus P4c800-E dlx.(vdimm modded and vdroop modded)

I've done de 3.3v sense wire mod on the psu but since there are no 12v and 5v sense wires i could perform the mods for those 2.
So I opened the psu and discovered that there where 2 very little pots looking at me. Started tweaking them and measring the volts on a spare molex. with nothing or 1 drive hooked to the psu I got the following.

12v ~ 12.28
5v ~5.08
3.3v ~3.61

I was happy with the 12v and the 3.3v but when i hooked the psu up to my rig I started having trouble.
My rig:
- Asus p4c800_e dlx (mods done)
- P4 3.2Ghz with zalman cu7000 now @3600
- Radeon 9800pro @ 9800XT With zalman vf770
- 4x 60gb in raid with promise TX2000
- Lite on 52x24x52 burner
- Nec 3500 Dvd burner
- Philips DVD player
- 80 GB wd in swapunit
- 1gb lan card
- Satellite card
- 3,5" drive
My bios measured the following when every thing was hooked up

12v ~ 11.631
5v ~4,941
3.3v ~3.58 (nice)

A spare molex showed me
12v ~11.91 :confused:
5v~4.4 :mad:
3.3v ~3,56(still good)

I've included some pics of my psu. Could you please help me out as to find a solution to my problem. I think if there is a way as to replace/bypass the tiny pots, I could bump up the voltages, right???
My harddisk are clicking because of the 5v /12v I think.

Many thnx in advance.
01-16-2005, 05:11 AM
Cyrus The Virus

hello I have a question about this mod.

In my rig I have a 20 to 24 Pins converter (new mobo and 1 year PSU) is it possible I mod the 3.3V sense wire on the converter (because I am not want to mod my PSU) and take the ground of a black wire ??
01-16-2005, 07:35 PM
Hell-Fire

Unless there are sense wires in the converter and ATX connector running off the supply, it will not work. There has to be a way for the signal to get from the converter to the supplies regulator.

Also, if there is not a sense wire on the cable running from the supply, even if there were to be one on an extender/converter that was modded, the mod would not work. The pcb of the supply has to have a sense wire present for this mod to work.
01-24-2005, 05:44 AM
rhino56

i think you are an alien because the stuff you were touching got a slime layer all over it
http://www4.ncsu.edu/~rwbradl2/Vmods/VRs_Mounted.jpg

haha j/k

awesome guide here, very easy to follow and understand.
great work HF
02-03-2005, 08:45 AM
I(illa Bee

Thanks, great guide...I was scared because a wile back (at lest 6 mounths, i tried this on the same PSU, and fried my Nf7 mobo... .. but this time is worked like a charm....

I didnt bother with the 12v line, it allready runs 12.2v under load and idel my DMM reads is 12.9.... I cranked the 3.3v to 3.42 for now, and my 5v. to 5.3v. Ill probely need more 3.3v when i get my water cooling up and start really overclcoking this 3500+, but i still need to figure out why my baord is undervolting the CPU,,lol

http://server2.uploadit.org/files/KillaBee-PSU1.jpg

http://server2.uploadit.org/files/KillaBee-PSU2.jpg

http://server2.uploadit.org/files/KillaBee-PSU3.jpg

http://server3.uploadit.org/files/KillaBee-PSU4.jpg
02-03-2005, 09:08 AM
eclypse

Anyone done this to a Zippy 700 watt? :)
02-05-2005, 07:27 PM
REDKEN

Hi guys!
I need some help here. I killed my PCP&C (don't ask) and bought myself a 510 OCZ Modstream. I tryed to do this mod on it but it didn't work.
I did everything by the book, but it always gave me a 4.50v. I don't know what I'm doing wrong.
02-06-2005, 12:45 AM
Hell-Fire

Can you post pics of your mods and of the psu?

Post pics of the psu's atx connector and of the inside of the psu.
02-07-2005, 03:48 AM
REDKEN

Quote:

Originally Posted by Hell-Fire

Can you post pics of your mods and of the psu?

Post pics of the psu's atx connector and of the inside of the psu.

I'll post pics as soon as I can retrieve my camera (lent it to a friend). For the moment, using a trial and error method I managed to set the PSU to 3.77v using a 10ohm and a 1ohm resistor in series which is about 0.05v less that what I'm looking for.
What I need now is a way to make it variable. After I finish writing this I'm going to look for a 15 or 20 ohm VR (if they even exist).

I'll see about those pics as soon as I can.

Thanks!
02-07-2005, 07:48 AM
I(illa Bee

FRAD, the ground wire and the + wire are backwards..... pod (+) gose on middel leg...
02-07-2005, 08:40 AM
Hell-Fire

Frad, can you post a pic of the entire ATX cable as well please sir. Showing the ATX connector up to where you did the mod.

Quote:

Originally Posted by REDKEN

I'll post pics as soon as I can retrieve my camera (lent it to a friend). For the moment, using a trial and error method I managed to set the PSU to 3.77v using a 10ohm and a 1ohm resistor in series which is about 0.05v less that what I'm looking for.
What I need now is a way to make it variable. After I finish writing this I'm going to look for a 15 or 20 ohm VR (if they even exist).

I'll see about those pics as soon as I can.

Thanks!

Yes, they make VRs as low as 10ohms. You can get them from DigiKey.com. They have COD ordering and delivey is fast.

Quote:

Originally Posted by I(illa Bee

FRAD, the ground wire and the + wire are backwards..... pod (+) gose on middel leg...

Shouldnt matter as long as its ground properly. You can send the live wire to either leg and it will work just the same.

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