How does someone know if their PSU went bad?

[ibex333]

My motherboard recently fried after working fine for more than two years. It doesn't even do a POST now. Someone suggested that my PSU is to blame.

But my PSU is not some cheap crap. I paid more than $100 for it when I bought it, and it was recommended back then by many people here on AT and elsewhere. All my PC fans are working, including the CPU fan, but the video card fan is dead, so I'm thinking that the mobo took the video card with it, or the power to the video card is not going through the mobo...

How can I know FOR SURE that it is indeed my PSU that is the problem? Are there any testing tools that I can purchase? Links/prices please? How do I use these tools? Any guides?

I don't have another hundred dollars for a PSU right now, unless I absolutely have to buy a new one.

 

[HOOfan 1]

A multimeter for $25 or so

link

 

[Gillbot]

Cheap multimeter for $2.50
http://www.harborfreight.com/c...m.taf?Itemnumber=90899

 

[Zap]

Originally posted by: Gillbot
Cheap multimeter for $2.50
http://www.harborfreight.com/c...m.taf?Itemnumber=90899

:Q Shipping would quadruple the cost!

 

[cubeless]

that pup ought to still have a warranty on it...

 

[techmanc]

I use on of these and it works great for me.................

http://www.frozencpu.com/produ...CI-E_Floppy_4_pin.html

 

[ibex333]

Thank you! I much rather use that gizmo than use a multimeter...

 

[techmanc]

Your Welcome and its pretty cheap for a nice gizmo.

 

[Zepper]

That device is nice, but it isn't very flexible, doesn't put much of a load on the PSU. With a meter, you can check the lines while the system is actually putting a load on the PSU. If you did anything with your hardware recently (install memory, etc.), I'd look at that first. Then, and after I'd checked my PSU lines with my meter, I'd reseat anything I could reseat: all internal power connections (inspect them closely for any signs of overheating), vid card, memory modules, etc., and CPU last (one at a time) and try another reboot after each. I'm hoping one of those will do it for you. Be sure to follow static precautions. Make sure all necessary power connectors have power from the PSU - mobo, vid card, etc.

.bh.

 

[techmanc]

Originally posted by: Zepper
That device is nice, but it isn't very flexible, doesn't put much of a load on the PSU. With a meter, you can check the lines while the system is actually putting a load on the PSU. If you did anything with your hardware recently (install memory, etc.), I'd look at that first. Then, and after I'd checked my PSU lines with my meter, I'd reseat anything I could reseat: all internal power connections (inspect them closely for any signs of overheating), vid card, memory modules, etc., and CPU last (one at a time) and try another reboot after each. I'm hoping one of those will do it for you. Be sure to follow static precautions. Make sure all necessary power connectors have power from the PSU - mobo, vid card, etc.

.bh.

Can you give about some information on how to setup and use the meter properly for PSU load testing?

 

[Zepper]

You don't have to set anything up. Just power up your system and use your probes to read each rail. If you want to do an analytical load test, you have to use something like the Sun Moon Star PSU load tester - not cheap.

.bh.

 

[ibex333]

Originally posted by: Zepper
You don't have to set anything up. Just power up your system and use your probes to read each rail. If you want to do an analytical load test, you have to use something like the Sun Moon Star PSU load tester - not cheap.

.bh.

I think what he meant is how do you use your probes to read each rail.. Where do you poke em? What are the "normal" readings, etc... (I think all that is in a guide here on AT though)

As for me, I feel very stupid right now, because I ordered a new mobo, (just got it today), put in my CPU, video card, and ram, powered on, and immediately noticed some very strange behavior... On 1st power up, the cpu fan wouldn't spin at all, but the video card fan span just fine. So did the PSU fan and the case fan. On the 2nd power up, the cpu fan span, but the video card fan didn't spin. Switched off again, and when I turned the system on for the 3rd time all fans spun everywhere, but they span in this strange way, sort of like when you see the motor trying to wind up on an old car... It's hard to explain but the fan spinning speed would fluctuate between trying to spin faster, then slowing down almost to a halt, then trying to spin faster again, then slowing down... (in fact, the led on my cpu fan would even go out for a split second every now and then) Yet again, powered off, and switched on for the 4th time... This time the fan on the CPU would not spin but the other fans worked fine...

At this point I am really regretting not listening to people when they told me it was the damned PSU right from the start... or is it?

Tomorrow I'm going to run to the radio shack, and spend $20+ on their overpriced multimeter, then some more on their overpriced battery that they don't include with the meter...

I don't want to wait until the FrozenCPU PSU tester ships to my address. Guess, I'll buy it later...


Since we're on the topic, can someone recommend me a PSU?

I need it to be able to handle an overclock, and be of good quality, but I don't want to get something that is too expensive either. Is there anything decent for sale right now that's well under $100? Thanx very much.

 

[Zepper]

You don't have to set anything up. Just power up your system and use your probes to read each rail. If you want to do an analytical load test, you have to use something like the Sun Moon Star PSU load tester - not cheap.

.bh.

 

[Quiksilver]

Originally posted by: Zepper
You don't have to set anything up. Just power up your system and use your probes to read each rail. If you want to do an analytical load test, you have to use something like the Sun Moon Star PSU load tester - not cheap.

.bh.

Zepper, he meant where to place the probes so he could read the rails.
Which case he should read the sticky on how to read PSU voltages.

 

[Zepper]

Well, if that's what he meant, just use the alligator clip on the black (ground/neg) lead and clip it to any good ground point like the chassis. Then slide the tip of the red probe (pos) into one or more each of the different colored wires (red, yellow, orange and any other voltages you may have (some may have -12V, but most no longer have -5V - it's so bad now that I've forgotten the standard color wire for those (I think maybe gray -5 and blue -12).The general rule is that you want the voltages to stay within +/-5% of nominal at any point within the rated load range.

.bh.

 

[ibex333]

Ok... Went out and got a multimeter... This is what I got:

For 3.3v I was getting anything from 2.99 to 3.08 and for a split second, I even hit 3.12 (maybe I didn't push in the red lead hard enough, but I didn't want to damage my psu connector or the mobo)
For 5v I was getting anything from 4.69 to 4.77, NEVER hitting 5.
For 12v I got from 11.95 to 12.05(rarely) with an average of about 11.98.

I am assuming this is NOT normal? Are the numbers supposed to be steady? My numbers fluctuated like crazy going from lows to highs and anything in between on every reading...

And again, sometimes the cpu fan would spin, and sometimes it would not.

 

[cusideabelincoln]

First, are you positive it's the motherboard? You should explain exactly what happens when you press the power button, noting any lights, fans, and etc that come on, stay on, or turn off. What steps have you taken to troubleshoot? Did you reset the BIOS?

If you have a spare computer, stick its power supply into your system. This would be a good test to verify a motherboard problem, although your problem could also be a bad video card.

The 3.3 and 5V look a bit low, and the 12V looks pretty good, but you can't really lean on these findings. If you have the power supply hooked to the dead system, it's probably draw a ridiculously low load, and also there are several 12V rails for the OCZ power supply so you should make sure to test the ones being used.

 

[ibex333]

Right..

I'll start from the beginning:

I woke up in the morning 2 days ago, and turned on my PC. I heard it turn on, like usual, but about 3 seconds later it suddenly turned off. Then turned on again, all by itself! Then turned off about 5 sec, later, then off again... It kept doing that again and again, so I got scared and switched the PSU off. I waited a few sec, then switched everything back on again. This time, the computer would no longer switch off, and stay on, but there was no video signal, and I couldn't hear the HD spinning up...


I opened up the system, and immediately noticed that my video card fan wasn't spinning. I was able to obtain a 7300GT from someone I know, and when I put that in, it's fan would spin just fine, but otherwise there was absolutely no change. After swiching off and on again, I started to notice more strange behavior like my cpu fan not spinning while the video card's fan would spin... Every time I'd switch off my system, the cpu fan would suddenly start spinning a split second before the power to the mobo went out due to me switching off the PSU. This immediately made me think that it might be the PSU, since when I switch it off I am assuming that most components lose power thus freeing power to the cpu fan that the psu didn't provide it with...

Oh, forgot to mention that I saw a small charred spot on the mobo where it says "TPM".

Anyway... Just to make sure that the CPU, mobo or the RAM are not causing all this, I ordered a new cpu, mobo, ram, and HD from newegg. My dad "conveniently" needed a new PC so I figured that whatever still works will go to him. And I'll have new parts to test my system with.

So, everything arrived yesterday, and I installed the new mobo, ram, and my OLD video card and OLD CPU. I figured the chances of my old cpu dying are next to zero because it was always sitting under a good cooler. (Zerotherm Nirvana) I didn't connect the HD and the sound card.

When I powered on, I noticed that my old video card's fan suddenly came alive and was spinning! So were all other fans in my system. BUT! Still no POST or video signal.

I put in my friend's 7300... NO CHANGE. (fan spinning fine)

I switched off and on agian, and this time my CPU fan was dead. When I pushed the off switch on the PSU, my CPU fan came alive for a second, like mentioned earlier.

Switched off and on AGAIN, and my cpu fan was spinning but the video card's was NOT.

I mean.. Shit... What are the odds of this new mobo or new ram being dead too? What are the odds of my old CPU being dead? Do you think I should try the new CPU just for the heck of it? (I really don't want to unpack it unless I have to)