Abnormal power supply voltage readings

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ilikecake

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Feb 20, 2006
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I recently had my Antec sp-500 die on me. I RMAd it back to Antec, recieved the replacement, and it seemed to work okay. However, I just got the new 7900GTO video card, and my computer is having problems again. Because the power supply died before, It is the primary suspect at this point.

I opened up the case, and used a multimeter to measure the voltage on one of the auxilary power plugs. I measured 19.74V on the 12V line (yellow to black), and 8.12V on the 5V line (red to black).

These voltages seem waayyy off. Is there a special way that I have to measure the voltage on the supply? or is my supply just really bad?
 
WHAT!?!?!?

That CAN NOT be right!

That's like "burst into flames" wrong. :(
 
Yeah, I kind of figured that I am not measuring the voltages right. I reseated the videocard, and it booted again. The MBM5 says 4.94V and 12.52V, but I have heard that the software is not to be trusted with this sort of thing.

Any tips on how to measure the voltages correctly?

Edit: I may have found the problem. My el-cheapo volt meter tells me a 1.5V battery has a voltage of 2.5V. Either I am missing somthing, or this volt meter was cheap for a reason...
 
You take a DMM (digital multi-meter) and you stick the probes into the backside of a connector.
 
Thanks for the info. As I said above, I am pretty sure my multimeter is either broken or horribly out of calibration. I guess I got what I paid for.
 
Hi

I recently got a good multimeter, and remeasured the voltages on the 5 and 12 volt rails. I now see:

5V - 5.043V
12V - 12.38V

So all seems to be well. However, my computer will randomly turn itself off. I occasionally leave my computer on when I go out and when I get back it is off. Is this possibly a power supply issue? Or is there anything else that could be causing this?
 
No Ideas? I also noticed that the computer now takes a few seconds from when I press the power button until the computer powers on. This was not the case before. And my computer did this right before my sp-500 power supply failed before. Does any of this sound like a power supply problem?

Any insight would be appreciated.
 
ilikecake said:
No Ideas? I also noticed that the computer now takes a few seconds from when I press the power button until the computer powers on. This was not the case before. And my computer did this right before my sp-500 power supply failed before. Does any of this sound like a power supply problem?

Any insight would be appreciated.
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Try a higher +12V amperage PSU like an Corsair 520W or OCZ GXS 600W & see if that solves your problems. ;)
 
I had a SP500 die on me and when I installed the replacement, it would not post when I pushed the power button. All the lights would turn on and the fans would spin but that was it. I had to wait a couple seconds after hitting the power button and then hit reset to get it to boot. My theory is one of the crappy capacitors in the thing took longer than it should have to come up to full charge. It sounds like you may be having a similar problem.

Is it just me or are there about a dozen threads floating around about SP500's failing?
 
The SP-500 doesn’t seem to be as good as I was expecting from Antec. Oh well, I guess it is time to try one of the new Corsair or Seasonic supplies.

Edit: has anyone had any success replacing capacitors inside the power supplies? I know it would ruin the warranty. But if I replace the supply anyway, it would be interesting to see if I can make it work well again.
 
ilikecake said:
Edit: has anyone had any success replacing capacitors inside the power supplies? I know it would ruin the warranty. But if I replace the supply anyway, it would be interesting to see if I can make it work well again.
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Yes - Antec's Channel Well made units are infamous for cooking their Fuhjyuus. Usually after a recap with decent parts, they turn into fantastic units. Use good quality caps from Panasonic, Nichicon, Rubycon, Sanyo, or United Chemi-Con; and be sure to make note of the physical size of the old caps so you can replace them with something that will fit.
 
Oklahoma Wolf said:
Yes - Antec's Channel Well made units are infamous for cooking their Fuhjyuus. Usually after a recap with decent parts, they turn into fantastic units. Use good quality caps from Panasonic, Nichicon, Rubycon, Sanyo, or United Chemi-Con; and be sure to make note of the physical size of the old caps so you can replace them with something that will fit.
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Yes indeed, but it usually takes a year or two for the caps to blow, as his is a new unit, I doubt this is the problem.
 
davidhammock200 said:
Yes indeed, but it usually takes a year or two for the caps to blow, as his is a new unit, I doubt this is the problem.
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Never claimed it was - I just responded to the capacitor question. It is still a possibility however... could have had a dud Fuhjyyu straight from the factory.
 
Oklahoma Wolf said:
Never claimed it was - I just responded to the capacitor question. It is still a possibility however... could have had a dud Fuhjyyu straight from the factory.
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That is always possible!

Do you know the wholesale cost difference between these caps & the better caps used by Seasonic?
 
Hearsay has it the difference amounts to about a couple dollars a unit. I guess it adds up over time, but that kind of cost cutting still drives me nuts.
 
Oklahoma Wolf said:
Hearsay has it the difference amounts to about a couple dollars a unit. I guess it adds up over time, but that kind of cost cutting still drives me nuts.
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I agree 100%! :rolleyes:
 
Will I be able to tell if I open the supply whether the caps have gone bad? Or would the power supply not work at all with bad caps?

On a different note: the supply I got back from Antec has pretty obviously been opened. Is it possible that they replaced the caps already or something?
 
ilikecake said:
Will I be able to tell if I open the supply whether the caps have gone bad? Or would the power supply not work at all with bad caps?
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Possibly... bulging and/or leaking are the obvious signs. An ESR meter is the only conclusive way to tell though.

Not sure what Antec does in the RMA process.
 
Thanks for all the information. When I replace this power supply, I will crack it open and see if I can make it work.
 
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