Are my PSU voltages too high?

[Denis54]

My computer is dead but the fan for my PSU still turns.

I have measured the voltages out of my PSU and get the following readings:

12V measures at 12.7 volts
5V measures at 6.2 volts
3.3V measures at 4.2 volts

Should I conclude that my 3 months old Corsair TX750 is defective? Did it kill my computer?

 

[Kirby64]

Those voltages are too high, especially the 5V and 3.3V lines. Are you sure those are being measured accurately? Have you tried another multimeter? If you're sure they are being measured correctly, it would seem likely that your computer could have been damaged by overvoltage.

 

[Stefan Payne]

Have you checked it with a voltmeter?

 

[MaxBurn]

Was this measured with a motherboard etc connected? Or was it measured by jumping out the power on signal? If you jumped it out then put the PS to use and measure again with a decent voltmeter.

 

[Denis54]

I jumped the power on signal. A case fan and a HD were connected. My motherboard is dead so I could not use it.

My voltmeter is a very high quality unit and I am sure it is accurate.

 

[CurseTheSky]

A quick and easy voltmeter test is to grab a battery - if you have a 9V and AA / AAA around, grab both.

The 9V should read somewhere around 8-9V depending on how dead it is. The AA and AAA should read around (but not higher than) 1.5V. If the batteries are coming up too high, your voltmeter is the culprit. Otherwise, you definitely have a bad PSU.

 

[Rifter]

yeah thats way off, for comparison my Corsair 850TX reads 12.5v, 5.3v and 3.4v with no load(jumpered)

and reads 12.3v 5.2v and 3.25v with all the load my system can throw at it(500W according to my UPS)

Those numbers are off, something is wrong.

 

[theAnimal]

My voltmeter is a very high quality unit and I am sure it is accurate.

And the batteries in your voltmeter are OK? Low batteries can give false readings.

 

[REC]

Super high voltages and a dead mobo? Going with a bad PSU fried the heck out of your mobo. DISCONNECT YOUR HARD DRIVE BEFORE DOING MORE TESTS.

With your 5vdc rail so high it will most definitely fry your Hard Drive if you keep it connected. It's pretty rare for a multimeter to read incorrectly (I don't deny that it's possible, just that it's likely). Get a second opinion if you like, but I'm fairly certain your PSU is shot.

Replace your PSU (and probably mobo) and run full hardware scans.