[Geminiwave]

This is the voltage recommendations made by Tom's Hardware Guide. Now see this is a big problem for me. In another thread I was making another whine about my graphics card and praying that someone had an answer. Someone indeed did. I did some investigating. Thank god for ASUS probe. Anyway THG claims that if your voltages on any of those goes lower than the min or higher than the max, that your PSU is suppose to shut down or something like that. Thats part of the ATX form factor.

[color=#ffffff]voltage[/color] [color=#ffffff]allowed variation[/color] [color=#ffffff]minimum voltage[/color] [color=#ffffff]maximum voltage[/color]
[color=#000000]+12 VDC[/color] [color=#000000]+/- 5%[/color] [color=#000000]+11.40 V[/color] [color=#000000]+12.60 V[/color]
[color=#000000]+3.3 VDC[/color] [color=#000000]+/- 5% [/color] [color=#000000]+3.14 V [/color] [color=#000000]+3.47 V
[/color] [color=#000000]+5 VDC [/color] [color=#000000]+/- 5% [/color] [color=#000000]+4.75 V [/color] [color=#000000]+5.25 V[/color]

Here is the part that has me worried. After leaving ASUS probe recording for the entire day, here are my findings.
under normal load it seems not too bad.
+12VDC=12.1v +5VDC=4.73v +3.3VDC=3.168 So these arent spectacular but they are pretty close. the +5 and +3.3 are getting close but they seem okay.

heres where the problems go though. Durring gaming(especially the bane of my existance...Halo PC) it changes. +5 goes to 4.95v(YAY!) and +3.3 goes to 3.0v (NOOOOOO!!!) Halo has been having SERIOUS graphical errors that have been getting worse and worse. I thought it was a driver issue or a heat issue. I added a HSF mod to my card and then added an extra fan and put in new drivers. things got worse. went to old drivers...things got WORSE.

I think I need a new PSU. If anyone thinks otherwise, stop me before i waste money.

Now if I AM getting a new PSU, are there any suggestions? I'd like to keep it as cheap as possible whilst still getting stable power and probably at least 380w. this 350 doesnt seem to have enough OOMPH to it.

Thanks alot!

edit: huh that pic didnt work right. ah well you get the idea.

[The_Neon_Cowboy]

with in 10% is with in spec and don't trust your bios
use a DMV (Digital voltage meter)

[Geminiwave]

alright...ummmm...know where i could get one? and then when i get one what do i do with it. I'm assuming i hook it up to the 3.3v plugs, neh? which ones though theres 4 pins arent there?

[The_Neon_Cowboy]

http://www.hardwareheaven.com/guides/psumod/index2.htm


most automotive shops, kmart, wallmart, radio shack, places like that... will have DVM's

get one and we can help you figure it out

[Vampyromaniac]

yes, test with a Voltmeter if you can, BIOS/software reading can be off by quite a bit.

Hey Neon, how do you test the +3.3v? (didn't see it in that guide)

[dj_stick]

isn't the green wire 3.3v? or the orange… i forget which one is which

[The_Neon_Cowboy]

Originally Posted by Vampyromaniac

yes, test with a Voltmeter if you can, BIOS/software reading can be off by quite a bit.

Hey Neon, how do you test the +3.3v? (didn't see it in that guide)

yea but he needs a dvm useally the 5V+ and 12+ rails are the ones
you worry about most... rarely are there 3.3 or 5 vsb issues if there is a problem it useakky more noticeable in 5V or 12V any ways

there is a way to test useing the mobo connector for the others



ATX Version 1.2 - 20 wire motherboard connector but here is the atx layout for you guys

[Matth]

Does it give "per rail" ratings on the side of the PSU ?
The +5/+3.3 rails also have a combined limit, as thet share a heatsink, and may share a regulator - it sounds like the AGP is dragging the 3.3v down, and te PSU is trying to compensate with the 5v sharing the same regulator.

I had 4.8v on my old PSU, and I was getting shutdowns - cheap PSU's can be false economy, and if you must go cheap, go considerably higher than you think you need - some cheap 400w models are no better on the power balance than a 300w, so if you're after a cheap one, 450w MINIMUM

[Geminiwave]

okay so what exactly do I need to do. I have an analog volt meter but its the one my old man uses and its very accurate. At the very least it'll give me an idea of how bad things are and I can get more details later. So what do I need to do? Unplug every PSU plug and then turn the thing on with it disconnected from my computer? And then hook it up ot the orange wires? How do I go about doing this. I'm alittle bit nervous especially when theres talk of PSUs exploding if you short it out.

[Matth]

Normally, you'd read the +12 and +5 off a spare drive connector, and the 3.3 with the meter negative to case or a power connector black, and the positive probe into one af the 3.3v connections from the back of the motherboard plug - on most plugs, the probe should make contact - if your voltages are reading that badly though, I'd say the PSU is not up to the task.

While the initial calibration accuracy of the PC monitoring is questionable, you can usually rely on the amount of change it indicates, sin the inaccuracy is only that the calibration was not trimmimed - just like the PC clock accuracy is usually pretty miserable.

[Geminiwave]

Hmmmmmmm... well in any case this is a problem that was not happening before...and is happening now. I think i'll just replace the PSU. But i might as well test it anyway.

so my question is...Do I just unplug the PSU completely from all parts of the computer and then test the 3.3v rail? Shoudl I leave some stuff plugged in? (like CD rom drive and fans or something?) im entirely unsure as to how I do this.

[Matth]

You can't start a PSU with no load - if you often have to diagnose PSUs, you would use a test load, but you can possibly get away with an old drive, and the flashing the green to ground (with a bent paperclip) to start.

So long as you are sure you can avoid slipping, I'd test without disconnecting anything, bing sure to safely fix the negative side, so you only have to worry about placing the positive probe - a standard meter probe should make contact easily, without pressing hard

[Geminiwave]

yeah but where am I putting the positive side. Where to i put it to scan the 3.3v rail. From what I got, it seemed like I was suppose to be testing one of the wires on the huge ATX connector right? the largest power connector. well how do I check the wire without disconnecting anything?

[swimtech]

Originally Posted by Matth

You can't start a PSU with no load - if you often have to diagnose PSUs, you would use a test load, but you can possibly get away with an old drive, and the flashing the green to ground (with a bent paperclip) to start.

So long as you are sure you can avoid slipping, I'd test without disconnecting anything, bing sure to safely fix the negative side, so you only have to worry about placing the positive probe - a standard meter probe should make contact easily, without pressing hard

Best way is to check with nothing disconnected, the unit running, case open with fullest access to the motherboard connector (the side panel off is generally fine). To test the 3.3v line, as Neon pointed out in the chart he posted, the orange wire is the one you want to put the positive (red) test probe onto, the negative probe (black) should be in contact with any black wire on any power lead (motherboard, hard drive, optical drive, etc...).

Now - how to check without disconnecting -turn off the computer and unplug it. Now gently push the probe into the same hole on the connector that the wire goes into. The probe will come into contact with a piece of metal that is on that is on the end of the wire inside the connector. There should be enough room in the hole the wire goes into to accept the probe and hold it up against the metal end of the wire in that hole. Now you should have your meters probes stuck into a couple holes of the power connector(s) - held by friction, without distorting or damaging the connector, and your hands are free.

Make absolutely sure at this point that you have your meter set to measure DC volts with a range up to about 20 volts, and turn on your meter. If you are uncomfortable with anything to this point, get some help from someone who is familiar with using a voltmeter on electronics - OK?

Now plug in your computer, turn it on, and monitor your chosen voltage. If you read 0, your leads are not making proper contact with the metal cap on the end of the wire in the power connector hole.

You can do the same with the 5v and 12v lines if you want. You won't have to move the negative (black) meter probe at all - just move the positive (red) meter probe into the hole on the connector you wish to monitor - red power supply wires for 5v, yellow power supply wire for 12v.

For safety's sake, turn off and uplug your computer before moving any probe leads though, that way if you slip you won't short anything. Just be careful...

[Geminiwave]

Ahhh Excelent guide there. I'm a total n00b when it comes to testing voltages. I was going to do it and my best friend was like "oh yeah be careful sometimes they explode" Great...real great...ahahah scared the shit outtah me. Now I'm alittle more comfortable.

I can keep it from shorting out.

Okay so do I just want it to touch one of the orange wires that do 3.3v or should i test mutiple wires? you said I CAN test the 12v and 5v but should I?

[swimtech]

The method is the same for checking the 12v (yellow) or 5v (red) lines as stated for checking the 3.3v line - the only difference is that the postive (red) meter probe would be inserted in the hole of the connector matching the color of the voltage you wish to monitor. You would want to shut down, unplug, move the positive meter probe into the line for, say, 12v, plug back in, power on, and monitor. The negative meter probe (black) need not be moved at all.

The 12v line is important for the CPU, video card, and drives - it seems to be the critical voltage to monitor for most problems I've seen here at DH (and likely therefore for the rest of the world - as we are a representative sample, I would say...).

Edit: With an analog meter (with a needle that moves across the face of the dial) remember to "zero out" the meter before each test for the sake of accuracy - your father (?) should be able to show you how to do that. Also test the meter on a battery (D cell, car battery - whatever) before you test your computer so that you can see the meter is working properly beforehand, and so you can safely train yourself on the use of the meter.

[Geminiwave]

I know how to use analog meters. im just borrowing it from my father. He has a ton of tools at his place that he never uses.

Oh yeah update, I got the analog meter. now its just a matter of doing the procedure.

You're sure this wont blow anything up as long as I dont short the wires out?

[swimtech]

Yup, I'm sure. I've done this many times - just make sure the leads on the meter are snug and in contact with the metal on the end of the wires inside the connector hole - skinny meter probes work best...