Guide: Power Supply Sense Wire Modding

**Hell-Fire** · 08-31-2004, 09:06 AM

No, this mod works with ANY psu that has the sense wires present.

And keep in mind that it works with supplies that have 1, 2, or 3 sense wires. All 3 do not have to be present to do a mod.

Also note that sometimes they shove the 5v sense wire in the middle of the ATX bundle versus putting it on the edges. Also, most of the time when only a 5v sense wire is present, that modding it also mods the 12v power rail as well.

I would open the psu and see whats there. You may find that there are VRs already included in the circuitry of the psu.

**David302** · 08-31-2004, 12:00 PM

Thanks a lot of reason I forgets open the PSU and look inside the PSU

**eclypse** · 09-26-2004, 08:14 AM

THANK YOU!!!!! Just what the doctor ordered! Perfect instructions and best of all.. Worked on the first attempt! THank god for that cause i also finally used my sleeving kit at the same time!

Works great on my Antec Truecontrol 550WATT P/S!

Have a beer on me

**Hell-Fire** · 09-27-2004, 11:35 PM

Glad it worked out for you bud.

Keep modding away...dont stop now.

**Espen** · 10-03-2004, 12:19 PM

Thanks for the great guide Hell-Fire :=)
Have just moded my Chieftec 420w HPC-420-302-DF PSU, it have only sense wires on the 3,3 line so i couldnt mod the 5/12v.
I was wondering if anyone know a way to mod the 12v on this psu because im getting as low as +11,22v when im running the cpu at high voltage. Moding the 3,3v line didnt help the +12v.
Thanks

Espen

**eclypse** · 10-03-2004, 07:06 PM

Wow i'd say just spend some cash and buy a new PS!

**Hell-Fire** · 10-04-2004, 11:51 AM

Espen, thats a pretty low line bud.

You can "sometimes" mod supplies without the sensee wires, but you need to open it up and see whats inside. You may get lucky and find it already has trimmers.

Other than that we would need to poke around to see what we find.

**eclypse** · 10-04-2004, 01:24 PM

I wouldnt even bother risking your life opening up that power supply with such a low 12v line.. That thing cant handle your computer! Buy something else.

**Jeff7** · 10-13-2004, 10:25 AM

Originally Posted by Da_BoKa

bios readings aren't always accurate, always use a multimeter

True words.
My NF7-S rev2 reports the following:
3.3V: 3.15 - 3.23V
+5V: 4.84 - 4.87V
+12V: 11.49 - 11.55V

A multimeter, testing the ATX power connector while the system was running reported:
3.3V: 3.31V
+5V: 4.98
+12V: 11.99V

I wish I could measure what the CPU and DIMM voltages actually are.
I do wonder why motherboards aren't made with better monitoring hardware. I mean, they've got incredibly advanced technology all over the place, but they can't do what any cheap voltmeter can do?

**eclypse** · 10-13-2004, 10:42 AM

I think testing it that was is still taking a reading off the P/S and not where the voltages are being used form the M/B.

**Jeff7** · 10-14-2004, 06:22 AM

Originally Posted by eclypse

I think testing it that was is still taking a reading off the P/S and not where the voltages are being used form the M/B.

So at least my power supply is putting out good voltage then, right?
Might those Motherboard Monitor readings in fact be accurate, from the point of view of the monitoring chip?
Could upping the PSU voltage slightly help increase the low voltages reported by MBM, without causing significant (besides that caused by normal overclocking) damage?

**flyersguy85** · 10-18-2004, 10:29 PM

what exactly are the benefits of modding a psu?? my thermaltake gives out 18A on the 12v rail...i have a OCed 3200+, flashed X800 PRO to XT, and ram is overclocked...will i get better performance in overclocking by doing this? or are theese mods only for if your psu can't meet your power needs?

How can i tell if my psu isn't powerful enough?

**Hell-Fire** · 10-19-2004, 05:31 AM

The benefits are typically more stable rails, and the ability to overclock ram further.

On most boards the ram is powered on the 3.3v rail, and since the Vdimm can never rise above more than 0.2v less than whatever the 3.3v rail is at, if you want say 3.45v on the Vdimm, you need a 3.3v rail of atleast 3.6-3.7v to be stable.

Also, not all psu are actually running what levels they should be...and dont trust the bios to give you the right readings. The 5v and 12v rails may be running well under their ratings.

**NapalmV5** · 10-19-2004, 05:15 PM

Awesome guide Hell-Fire,

Modded my Enermax 651's 3.3v rail thanx to your guide.

**spaceman** · 10-19-2004, 06:47 PM

Excellent stuff, Hell-Fire, thanx!

I'm looking at doing the 3.3v and 12v lines on my PCP&C 510 Deluxe. Now my question is, would this be better, worse, or no diff, from changing out the VRs already there? I was just looking at the other thread, before I saw this. And if I just do the sense mods, can I use another VR WITH the one already being there, on the PCB? Sorry for being such a n00b, but I saw where you said too many VRs isn't good. And finally, if it's best to just change out the stock ones with 2k ones, can I just buy a couple from you? The Radio Shack's around here have very limited stock, and they always seem to be out of whatever I'm looking for.

Thanx again.

**sparkie34** · 10-19-2004, 07:12 PM

Just modded my 3.3 line tonight. Cruising now at 3.6. Now i'm able to give my ram up to 3.5v. Thanks Hellfire for the help on this mod and the vtt mod.

**Hell-Fire** · 10-19-2004, 07:45 PM

Originally Posted by spaceman

Excellent stuff, Hell-Fire, thanx!

I'm looking at doing the 3.3v and 12v lines on my PCP&C 510 Deluxe. Now my question is, would this be better, worse, or no diff, from changing out the VRs already there? I was just looking at the other thread, before I saw this. And if I just do the sense mods, can I use another VR WITH the one already being there, on the PCB? Sorry for being such a n00b, but I saw where you said too many VRs isn't good. And finally, if it's best to just change out the stock ones with 2k ones, can I just buy a couple from you? The Radio Shack's around here have very limited stock, and they always seem to be out of whatever I'm looking for.

Thanx again.

Thanks bro. =D

I would recommend swapping out the internal VRs, although adding an additional VR wont hurt things either. It all depends on how comfortable you are with removing the stock ones versus doing the sense wire mod.

I would be glad to send you some, but I dont have any on hand..in fact I ordered some 2 weeks ago and they havent shown up yet..thanks for reminding me..lol.

You can get them from CircuitSpecialists among other places.

Originally Posted by sparkie34

Just modded my 3.3 line tonight. Cruising now at 3.6. Now i'm able to give my ram up to 3.5v. Thanks Hellfire for the help on this mod and the vtt mod.

My pleasure sir.

**spaceman** · 10-19-2004, 07:50 PM

Awesome, I'll order some up, thanx.

Yeah, I'm not an expert solderer, but changing them out is probly better. Not only would they be good & sturdy on the PCB, but I wouldn't need to drill any new holes, lol.

Edited: Zoinks, they're only .79 each, but shipping would be $9! Maybe I'll pursue this further locally.

**Hell-Fire** · 10-19-2004, 07:52 PM

Just be careful not to drop any solder balls down into the psu while removing the stock ones bud.

**spaceman** · 10-19-2004, 08:06 PM

Originally Posted by Hell-Fire

Just be careful not to drop any solder balls down into the psu while removing the stock ones bud.

Roger that. I'll just throw a wet towel behind it. Doh, no wait, that's for soldering pipes, lol.

**elec999** · 10-20-2004, 01:40 PM

WIll this mod work with any power supply or most of them. ALso if I want stable vcore and vmem volts will I need to mod the 5v rail and the 3.3. I am also modding the motherboard.
Thanks

**mgv101** · 10-23-2004, 07:36 AM

I couldn't stand the poor timings on my RAM anymore so I've finally decided to mod my enermax EG475P-E's 3.3V line so I could hit above 3.1 Vdimm.

Well... the mod did not work for me

I've tried it with and without the fixed resistor and made sure all the soldering was done properly but still, no matter how much I turned the pot the voltage wouldn't budge at all.

Maybe this PSU is special as I've also realized that there are no Vsense line for the 12 and 5V rails.

**disco_bazoon** · 10-23-2004, 07:58 AM

Excellent guide, with excellent pics!
Got the parts I needed to do this today, so I will be doing it ASAP.
:banana4: (yes, I felt you deserved the bob marley banana

)

Oh, one thing, would it be okay to use 20k VR's aswell? Got more of those than the 10k's
Also, in some other guide I saw, he used different resistors and vr's for the different rails. Large ones for the 12v rail, small ones for the 3.3v rail. Any point in that?

**Hell-Fire** · 10-24-2004, 07:58 PM

If there is a sense line, then the mod should work if done properly.

Cam you post pics of your mod?

**disco_bazoon** · 10-30-2004, 06:30 AM

Well, I did the mod yesterday, and it worked out fine. Everything seems to work okay, running the 3.3v @ ~3.6v, 5v @ ~5.3v and the 12v @ ~ 12.6v.
The only problem I have now is that the harddrive activity light lights up slightly all the time, lol. Any idea why that would happen?

Edit: Stupid me, a molex had fallen off my dvd-rw, causing the hdd activity light to be on all the time

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