CrazeD
Member
+368|6643|Maine
I, at one time, didn't know how to accurately measure the power my PSU was giving out. I learned how to and this is a guide for anyone who doesn't know how to measure your PSU rails.

Ok, first you need a multimeter that can handle 15 DC volts. You can get a cheap one (like mine) at Radio Shack for about 15$.

Next, we need to understand which wires do what on the power supply. You will be dealing with only four different wires, here they are:

YELLOW - This is your +12V rail
RED - This is your +5V rail
ORANGE - This is your +3.3V rail
BLACK - This is a ground

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0654.jpg

** Before we continue, please make sure that you NEVER touch the two test probes on your multimeter together while the unit is switched on. This could damage the multimeter. Also, never allow the test probes to touch the incorrect wires (IE: negative probe onto a positive lead, or the positive probe onto a negative lead) as that could damage the unit and/or whatever you are testing. **

There is two ways to do this. Method one is easier than method two, but it requires a power supply with a 20+4 pin connector. Method two works just as well, but takes a tad longer.

METHOD ONE:

With your PC off, switch the power supply off and unplug all devices connected to it (except the motherboard). Take your multimeter and set it to 15DCV. Now, grab a molex plug and stick the black (negative) test probe into either of the two black pins on the molex. Make sure it stays in place, you don't want it to fall out. Also make sure that it doesn't contact any metal or anything conductive.

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0656.jpg

Disconnect the 4pin connector from the 20pin ATX connector block. You will have one orange, one yellow, one black, and one red wire coming out of this plug.

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0657.jpg

Switch on your power supply. and turn on your PC. Make sure you don't allow the red (positive) test probe to touch any metal or wires.

Take your red (positive) test probe and decide which rail you'd like to test. As mentioned above, you can test the +12V, the +5V, and the +3.3V rails with this plug.

To test, simply touch the end of the red (positive) test probe to the corresponding wire. IE: To test the +12V rail, touch the test probe to the tip of the YELLOW pin.

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0659.jpg

METHOD TWO:

If you don't have a 20+4 pin ATX connector, or don't feel like taking the 4pin connector off, use this method.

For method two, we have to use the molex and 20pin ATX connector.

Insert the black (negative) test probe into either black pin. Insert the red (positive) test probe into the yellow pin. This will give you your +12V rail measurement.

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0660.jpg

Insert the black (negative) test probe into either black pin, and insert the red (positive) test probe into the red pin. This gives you the +5V reading.

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0661.jpg

For the +3.3V reading, it gets a little tricky. Stick the black (negative) test probe into either black pin on the molex connector. Then, take your red (positive) test probe and cram it into the fitting on the back of the orange pin on the 20pin ATX connector. You should have enough room to get the test probe in there. Make sure you use the ORANGE wire (there are several orange ones, any will do).

https://i13.photobucket.com/albums/a283/crazed_rider/HPIM0665.jpg


Remember that having unplugged all devices, this is your voltages are idle. Jot this down, and then plug all your devices back in and test it again. Write this down, and then run prime95 (In-place large FFT's) and then test voltages again. You could even run 3DmarkXX or play an intense video game and again check the voltages.

The point I'm trying to get across is that as the system strains, it draws more power. IE: A video card consumes a lot more power more in 3D mode than in 2D mode, etc.



Hope someone learned something from this guide.

Enjoy.
kylef
Gone
+1,352|6463|N. Ireland
Handy Guide (sticky request). Although most people don't have the required tools etc. Very pictorial and helpful, +1 for you.
unnamednewbie13
Moderator
+2,053|6742|PNW

leetkyle wrote:

Handy Guide (sticky request). Although most people don't have the required tools etc. Very pictorial and helpful, +1 for you.
A multimeter and a couple of leads aren't going to cost much, when compared to the price of a new PC. Just make sure you don't screw up.
Mad Ad
Member
+178|6481|England, UK
and remember kiddies, get it wrong and you too can have a PC like this!


https://homepage.ntlworld.com/adspace/pics/burnt_computer.jpg





Nice one CrazeD +1
The Stillhouse Kid
Licensed Televulcanologist
+126|6612|Deep In The South Of Texas
Good guide, I 2nd the sticky nomination.

I don't trust software voltage monitors anymore due to this method of testing. Software reports my 12v as 11.86v, but using the multimeter it never drops below 12.2v on a full load.
CrazeD
Member
+368|6643|Maine

The Stillhouse Kid wrote:

Good guide, I 2nd the sticky nomination.

I don't trust software voltage monitors anymore due to this method of testing. Software reports my 12v as 11.86v, but using the multimeter it never drops below 12.2v on a full load.
Man, software measures my Antec Smartpower 2.0 500w at 9.56V on the +12V rail...lmao.
misconfiguration
GURU
+86|6366|Indianapolis, IN
I thought I was the only one that still uses a multimeter, kudos mate!
Bertster7
Confused Pothead
+1,101|6551|SE London

I've always done it with an oscilloscope before (not for a while - I did knock up my own PSU before, it wasn't great and did eventually sort of explode (regulators did their job and saved the PC though)). But I suppose a voltmeter should be fine and much, much cheaper.

Ideally you want to use this
https://www.shipol.com.cn/picture/4364020051226110828.jpg
and this
https://www.statron.de/images/jpeg/3229-0.jpg
King_County_Downy
shitfaced
+2,791|6567|Seattle

That's a very nice guide I must say. I made one of those multimeters in college, used to stash my marijuana seeds in it so my parents wouldn't find them. anyways, I love using the multimeter but I have found something that's much easier if you only want to know if the PSU is good or not. (obviously this wouldn't give you the exact wattage/voltage, etc. but...) Check these out: http://www.cluboverclocker.com/reviews/ … /index.htm about the same price, specifically for PSU's.
Sober enough to know what I'm doing, drunk enough to really enjoy doing it
CrazeD
Member
+368|6643|Maine
You only want to find the voltages, to make sure everything is okay. Like you can have a PSU with a crappy +12V rail voltage, that's at like 11.5... it will work, just not very well.
_j5689_
Dreads & Bergers
+364|6687|Riva, MD
I see you have a pos Sound Blaster 16 Pre-Amp.  It looks like i'm not the only one that recognizes the benefits of an NIC over on-board LAN.

Last edited by _j5689_ (2007-01-08 16:07:11)

CrazeD
Member
+368|6643|Maine
It's my old system, lol.
_j5689_
Dreads & Bergers
+364|6687|Riva, MD

CrazeD wrote:

It's my old system, lol.
Do yourself a favor and keep using NICs.  I was using one I found in the garage and popped it in: my pages loaded 50% faster, less connection problems, and I dropped 15 ping.  I gave one to my friend who is using DSL, same benefits as well as the fact that he can now actually kill people in CS:S, and he can actually finish his downloads now because they don't take nearly as long.  I know it sounds crazy but isn't 18$ for an NIC worth a try.  I bullshit you not.
CrazeD
Member
+368|6643|Maine
I only have a NIC cause all the onboard stuff on that board is fried, lol.

A NIC will not change anything really, unless it has a better connection to your network or has been configured differently. If you have a 10mbit onboard ethernet and buy a 100mbit NIC (providing you have a router with 100mbit ports) then ya you'll see a difference. Otherwise, you won't.
_j5689_
Dreads & Bergers
+364|6687|Riva, MD

CrazeD wrote:

I only have a NIC cause all the onboard stuff on that board is fried, lol.

A NIC will not change anything really, unless it has a better connection to your network or has been configured differently. If you have a 10mbit onboard ethernet and buy a 100mbit NIC (providing you have a router with 100mbit ports) then ya you'll see a difference. Otherwise, you won't.
I know I definately did.  Until my mom bitched at my dad enough about the ethernet cords going across the living room and I had to switch to shitty wireless.
Kmar
Truth is my Bitch
+5,695|6571|132 and Bush

This forum needs a entire guide section.
Xbone Stormsurgezz
_j5689_
Dreads & Bergers
+364|6687|Riva, MD

Kmarion wrote:

This forum needs a entire guide section.
Yes, very much.
CrazeD
Member
+368|6643|Maine

_j5689_ wrote:

CrazeD wrote:

I only have a NIC cause all the onboard stuff on that board is fried, lol.

A NIC will not change anything really, unless it has a better connection to your network or has been configured differently. If you have a 10mbit onboard ethernet and buy a 100mbit NIC (providing you have a router with 100mbit ports) then ya you'll see a difference. Otherwise, you won't.
I know I definately did.  Until my mom bitched at my dad enough about the ethernet cords going across the living room and I had to switch to shitty wireless.
Ew....wireless.

My cords go under the floor...there is like 502305667 wires dangling from the ceiling in my basement, lol.

How did we get on about NIC's from PSU testing anyway?

Board footer

Privacy Policy - © 2024 Jeff Minard