PSU failure: voltages too low - possible damage?

[seanspotatobiz]

For a few months I experienced BSODs that related to graphics card drivers.

A couple of weeks ago my computer would not boot (the fans all started but the power LED appeared to flicker). I measured some of the PSU (Thermaltake 705w 700 W, now eight years old) voltages and the 12 V output was 10.3 V and the 5 V output was 3.5 V. I bought a new PSU (XFX TS 750 W - more than adequate), however the PC will not boot.

The POST speaker emits a single long beep which repeats after several seconds, perhaps suggesting that the PC is repeatedly resetting. I have uploaded an audio recording here.

Could anyone advise on:

• how to proceed?
• the probable mode of failure of the PSU (now eight years old; I've opened and inspected it and can't see any obvious damage)?
• the possible damage sustained by the other components (I was under the impression that under voltage was not a risk)?

My computer contains the following components (among others):

OS: Win 7 64-bit
Mainboard: Gigabyte GA 790FXTA-UD5
CPU: AMD Phenom II 965 X4
RAM: OCZ Black Ed 2x2GB DDR3-1600 + Corsair 2x2GB DDR3-1600
Graphics: 2 x Crossfired Sapphire HD 5770 1GB GDDR5

 

[johnb35]

To be within specs of a power supply unit, the voltages must be plus or minus 10 percent. So 12 volts should be + or - 1.2 volts, 5 volts should be + or - .5 and the 3 volt should be + or - .3 volts. If the video card isn't getting enough power to run it properly then you can get bluescreens from it.

Have you tried resetting the cmos?

 

[seanspotatobiz]

To be within specs of a power supply unit, the voltages must be plus or minus 10 percent. So 12 volts should be + or - 1.2 volts, 5 volts should be + or - .5 and the 3 volt should be + or - .3 volts. If the video card isn't getting enough power to run it properly then you can get bluescreens from it.

Have you tried resetting the cmos?

Indeed, I'm aware the voltages are out of spec and that's why I bought a new PSU. I've not tried resetting the CMOS because I didn't think that'd help and I can't remember how my RAID is set up.

Edit: I've reset the CMOS but it didn't help. I'll have wait for the speaker.

I was hoping someone might confirm or allay my concerns in the meantime though.

 

[StrangleHold]

You got the 8 pin CPU power connector plugged in? Got both 6 pin PCIe power connectors plugged into your cards?

 

[seanspotatobiz]

You got the 8 pin CPU power connector plugged in? Got both 6 pin PCIe power connectors plugged into your cards?

Never mind. The new PSU fixed the issue. One of the RAM DIMMs wasn't inserted fully which is why it wouldn't start after putting in the new PSU. Sorry for wasting your time, StrangleHold!