Testing PSU thoroughly? Like with a mulitmeter?

[spystyle]

I had a PSU that stopped supplying enough power to run a large hard drive (200 GB) but still worked fine on a small hard drive (5 GB) - it was a 400 watt PSU, it passed testing with two PSU "testers" - an Antec and PowMax.

If my regular testing routine (the two PSU testers) didn't cut it in this instance - what else can I do? Test it with a multimeter? How would I do that? And how can I test the power strip and outlet that it draws power from?

Thank you,
Craig

[Samstag]

The supply testers you're using don't put any signifigant load on the supply, so they won't catch a weak supply like you may have (the 200G drive could be the culprit).  I'm not aware of any consumer testers that can find that kind of problem.

With the system running on the 5G drive you can put a voltmeter on the 5/12v lines and probably see the problem.  Depending on the effect the 200G drive has you can do the same with it installed to compare.  But that really isn't going to be helpful information unless you plan to try to fix the supply.  Your best bet is to figure out whether the supply or the drive is causing the problem and throw away the bad part.

[ChadTower]

You want to test that drive on another PS... it could be a drive problem.

[spystyle]

You want to test that drive on another PS... it could be a drive problem.

I did for sure -

The 200 GB drive is running perfectly now on a different PSU, it's been tested with HDtune and Spinrite and is working great.

[spystyle]

...Your best bet is to figure out whether the supply or the drive is causing the problem and throw away the bad part.

Truly, I was just wondering if there were steps I could add to my "PSU testing routine" - I lost allot of time over this PSU.

I figured there could be a thorough test for the PSU and also a way to test it's source - the power strip and wall socket.

I guess there aren't any computer techs who are also electricians in the room?

Thanks,
Craig

[ChadTower]

I would look up the current draw of both hard drives, then determine the difference.   Then I'd find a way to simulate that additional load on the PSU, maybe adding a little bit progressively until it fails.

[Com[Plex]]

I figured there could be a thorough test for the PSU and also a way to test it's source - the power strip and wall socket.

I think your answer is simple, and right there in front of you.
if the PSU works with your 200 gigger, it must be OK. if not, then you might want to consider getting a new psu.

probably not the answer you are looking for...

[spystyle]

You're all fired

:)

[BobA]

You can test any supply with a multimeter but you also have to test it under load.   You can make up a load tester by using a bunch of power resistors and a switch.   Many arcade testers have a way to test the PS under different loads.   If you measured the voltages with your 200 Gig drive plugged in you would probably see with your multimeter that one or more of the voltages were pulled down to unacceptable levels.   

If you do not test under load you are not testing.    I give plug in power testers 2 out of 5 power supply testing points.

[Samstag]

...Your best bet is to figure out whether the supply or the drive is causing the problem and throw away the bad part.

Truly, I was just wondering if there were steps I could add to my "PSU testing routine" - I lost allot of time over this PSU.

I figured there could be a thorough test for the PSU and also a way to test it's source - the power strip and wall socket.

I guess there aren't any computer techs who are also electricians in the room?

Thanks,
Craig

You can test more thoroughly but I was trying to get the point across that it's not worth the effort.  If you really want to test your supply correctly you need to have a custom testbed with variable loads.  Yeah, you can half-ass it with big resistors and old hard drives but unless you know what you're doing you're probably not going to get accurate results.

What you would need to do for a minimal test setup is:

• Put a small load on each of the 3.3, +5, and +12 lines.
• Measure current in series with the load you want to test.
• Increase the load in steps and verify the current/voltage until you approach the rated current.
• Repeat for each output (3.3, 5, 12)

I'm an electronics guy and have access to expensive variable load testbeds at work.  Here are my power supply testing steps:

• Replace suspect supply with a $20 500W supply.
• If it works, order a new supply.

Get yourself a cheap spare supply and sell your testers.

[spystyle]

Thanks all

:)

[shmokes]

I always keep extra power supplies on hand cos of their high failure rate.  When I suspect a bad power supply I test the drive leads with the PC running, if it will run(can only check the 5 and 3 volt since I can't access the motherboard cable).  If the computer won't even turn on I try to short the green and black.  Beyond that, I throw in a new power supply and if the problem is solved I toss the old power supply.  It's a commodity component that is not worth the trouble of trouble-shooting more thoroughly.  My salary costs money.  No use paying what it would cost to get a new power just so I can determine exactly why we need to get a new power supply.

Of course, this is in a corporate setting, not at home.  But a quality 400 W power supply can be had under $50.

[leapinlew]

I think I know where spystyle is coming from here.

It would be nice to have some sort of simple diagnostic tool. "Suspecting" the PSU is often the problem and I too have wasted a lot of time and effort tracking down a faulty PSU. Often times, the problem doesn't appear to be coming from the PSU.

Sure, 400watt power supplies are inexpensive, but how about a 700watt power supply thats running a SATA RAID on a new system? This is what recently happened to me. Since the whole system was new and the symptom was random lockups - the issue could have been nearly anything.

I updated the firmware (Raid controller + BIOS) - still locked up
disabled all unneeded services - still locked up
removed the raid controller - no more locks ups. I was thinking at this point perhaps it was 1 of the 16 drives, the drivers for the raid controller, a driver conflict or the PSU.
Eventually I swapped in a new PSU and it's been running for over 6 months.

What made my issue worse was that the server didn't lock up 30 seconds after bootup - it would lockup randomly a few times a week. All I could do is try something and check back on it. 

I can understand the desire to quickly determine if the PSU is flaking out.