PSU undervolting

[malcom]

Hi all,

I've been browsing this forum for quite some time but this is my first post.

I recently built a budget computer for my friend and now the computer randomly restarts all the time. My first guess was that is must have something to do with the psu since its a cheap generic psu.

Voltages are as follows:

Idle:
3.3V = 3.23V
5V = 4.85V
12V = 11.6V

under load:
3.3V = 3.2V
5V = 4.8V
12V = 11.46V

My question is: are the voltages low enough to cause the system to crash?

thanks in advance

 

[malcom]

I myself would never buy a cheap psu, but my friend insisted on getting a cheap psu since he was under budget.

The psu is an Atrix 520W, 25A on the 12V rail(only one rail)

 

[Vinny]

I wouldn't say that its only a problem with cheap PSes... my OCZ got fantastic reviews and is far from cheap (set me back $150) yet I'm only getting 11.52A on my +12V rail.

I'm guessing I got a somewhat bad unit or that I need to adjust the rails.

 

[malcom]

Problem solved, but thanks for the input anyway.

First of all maybe I should post the spec:

AMD X2 4200+ AM2
ASUS M2N-E
2x512MB Corsair XMS2 5400 C4
Club3D 7600GT
160GB Seagate Sata2
Atrix 520W psu

It was the bios(0103) that caused the random restarts (found this on an asus support page). I upgraded the bios to 0203 and set the ram settings/timings manually according to corsair specifications. After upgrading the bios the voltage readings changed to the following:

3.3V = 3.35V
5V = 5,1V
12V = 12,4V

Now the system seems to be stable, no random restarts so far.

 

[malcom]

The system has been running for three days now without crashing/rebooting. Seems like the bios update really solved the problem.

 

[Pain]

Glad you solved the problem, and just so you know for future reference, don't put too much value on the readings you get in the monitors programs. They really don't tell you much, if any, usefull information.

 

[trixst4r]

how would a person adjust a rail?

You don't. Unless you have a vast understanding of how a PSU works and you know witch parts to change out to give you more power. PSU are not forgiving to mistakes. I tried building an ac to dc ajustible power converter to run test on other projects i was working on. Well i had on capasitor in backwards. I pluged it in and turned it on and the thing blew apart one of the copper strips on the PCB. So i tested everything an fixed the PCB. Still i didn't see the one catasitor was backwards. Tried everything again and the whole thing caught fire after a lot of sparking and poping. It was quite a show.

working with polar electrolytic caps i see. I didn't realize they caused so much damage. The only thing I saw when one of the other students in the lab put it on backwards was taht it kinda exploded and shot out of the breadboard, but that was a small cap.

 

[Vinny]

how would a person adjust a rail?

You don't. Unless you have a vast understanding of how a PSU works and you know witch parts to change out to give you more power. PSU are not forgiving to mistakes. I tried building an ac to dc ajustible power converter to run test on other projects i was working on. Well i had on capasitor in backwards. I pluged it in and turned it on and the thing blew apart one of the copper strips on the PCB. So i tested everything an fixed the PCB. Still i didn't see the one catasitor was backwards. Tried everything again and the whole thing caught fire after a lot of sparking and poping. It was quite a show.

The OCZ PowerStream series has adjustable rails.

ASUS Probe gave me 3.12, 5.27, and 11.43 (I'm sure you can guess on what rails) but with a slight adjustment I was able to get 3.32, 5.08, and 12.11.

 

[Pain]

8O

Measured with what? If you aren't measuring it with a scope I wouldn't even attempt it.