Bad Capacitors or PSU Problem?

[Tom41]

Re: Bad Capacitors or PSU Problem?

I've always wondered why there's so much glue inside PSUs. The 'Suntek' PSU that died on my home machine seemed to have very little, if any, glue on the components. It would often make a loud hissing noise (especially when first powered up), which I assume was the transformer windings or torroid coils vibrating.
The new PSU I have doesn't hiss at all, but as it's still under warranty I haven't opened it up to check for glue

The best way to check for impending PSU failure due to bad caps is to connect the DC output lines to an oscilloscope. If you get a perfectly smooth line on the display, it's outputting a constant voltage and should be safe for your system. If you see little 'wrinkles' in the line, or even a waveform, that's bad - your PSU isn't producing a steady current and could cause bad cap symptoms on your PC. If you see a line waving up and down randomly, that's REALLY bad... it means the voltage output isn't regulated at all. For all you know, it could suddenly pump 12v into the 5v line and fry your components!

If you don't have an oscilloscope, use a multimeter and set it to the highest precision possible. On mine this is 2 decimal places - all digits should stay at the same value constantly. If it fluctuates, you may have a bad PSU.

[Rainbow]

Re: Bad Capacitors or PSU Problem?

Digital multimeter is too slow to notice.

[saxman285]

Re: Bad Capacitors or PSU Problem?

How long should the BURNK7.exe and BURNMMX.exe be run for to expect to have them cause a powercut?

Also, when running BURNK7.exe, the task manager shows only a 50% cpu usage. Am i doing something wrong so it isnt stressing the cpu like it should?

[Spacedye69]

Re: Bad Capacitors or PSU Problem?

I originaly bought my old analog meter just to check ps voltage. Works well for med to large fluctuations. Does anyone know of a way to reliably, perferably adjustable, put a large load on a ps without back probing while plugged into mobo? A schematic for one like they use on the ps reviews would be cool also.

[tiresias]

Re: Bad Capacitors or PSU Problem?

Also, when running BURNK7.exe, the task manager shows only a 50% cpu usage. Am i doing something wrong so it isnt stressing the cpu like it should?

Seriously? Is the other 50% "System Idle process", or some other process that's "slurping up" the CPU time? Could you check that? You have a Northwood so the "burn" applications should work without incident.

How long should the BURNK7.exe and BURNMMX.exe be run for to expect to have them cause a powercut?

Well, it depends what cause you're trying to exclude; if you're trying to assess whether the PSU shuts down due to some perceived "overload" of any of its rails, it should only take seconds. If heat generation and accumulation is the problem, on the other hand, it will take longer.

But a word of warning: as I said before, non-reproducible, random, shutdowns are a very generic symptom - if the problem lies with, or within the motherboard's PCB (as opposed to one of its discrete, replaceable components) narrowing down the fault may be all but impossible. As the wise kc8adu mentioned, even a loose connection to the CPU socket is a possibility. Another example - I have an ECS socket A motherboard that will lock up hard every time it's moved or shaken a little - it will do this even outside of a chassis, so it's not due to any 'shorting to the case' issue.

In any case, Saxman, see if you can at least narrow it down to the motherboard, and let us know of your progress

[saxman285]

Bad Capacitors or PSU Problem?

Seriously? Is the other 50% "System Idle process", or some other process that's "slurping up" the CPU time? Could you check that? You have a Northwood so the "burn" applications should work without incident.

Yes, the other 50% is System Idle Process. It is using EXACTLY 50% at all times. This is very consistent and the CPU Usage only increases to 51-54%ish if something else is using a little (like 50% BURNK7, 1% taskmgr as i scroll through the processes).

[Chris1992]

Re: Bad Capacitors or PSU Problem?

that's because you have hyperthreading and task manager is too stupid to know burnk7 is really taking 100%cpu. I encounter the same with f@h.

[saxman285]

Re: Bad Capacitors or PSU Problem?

so that means its working just as it should?

[Chris1992]

Re: Bad Capacitors or PSU Problem?

yes. Assuming your CPU has HT, anyway.

[saxman285]

Re: Bad Capacitors or PSU Problem?

Yes, my cpu has HT, and i ran it for awhile without any shutdown. So i guess since you said it should happen almost instantly, its probably not the CPU. I'll have to run the BURNMMX like you suggested, but it has more options than the other tests. What do i set the RAM size to? The default is 64 kB, but it ranges from 2 kB to 64MB.

[saxman285]

Re: Bad Capacitors or PSU Problem?

What do i set the RAM size to?

can anybody help me with running this test?

[tiresias]

Re: Bad Capacitors or PSU Problem?

Hi Saxman,

Sorry about that - hadn't seen your question.

Well, realistically, if you're testing for power/heat issues, burnk7's load will be far greater than any burnmmx setting, the latter being really just an intense memory tester.

I had mentioned burnmmx as an alternative for Memtest, since you can actually use your computer while it's running, while memtest needs it's own 'OS'. As for the memory size, I usually choose the next size up starting from the used CPU's total cache. So with a Northwood with 1MB L2 cache, I would normally use option 'K' for 2MB.

Have you had any more luck with your troubleshooting? Are you any closer to isolating the problematic component - which is, all things considered, probably the motherboard - which, in turn, could be the PCB or something soldered on to it.

[saxman285]

Re: Bad Capacitors or PSU Problem?

well, i dont really have an alternate power supply i can put in the computer to see if thats the problem, so i cant really see if that would eliminate it (and i definitely havent ruled out the PSU). The power draw doesnt seem to be an issue if running the BURNK7 for a few hours didnt do anything. I guess i'll have to continue my search for a temporary test PSU if theres nothing else i can do to identify the problem component.


btw, thanks a ton for all your help here. Keeps me from feeling like just throwing the whole thing out the window.

[saxman285]

Re: Bad Capacitors or PSU Problem?

Ok, sorry for the bump of a really really old thread, but theres finally something new here. I finally had the extra cash to pick up another PSU, and after installing it, the problem persisted almost imediately. My computer got through booting, and was opening startup windows programs, and boom, power loss. This obviously rules out the PSU, so is it pretty definite that I need to replace my Mobo capacitors?

[trodas]

Re: Bad Capacitors or PSU Problem?

Based on the informations you provide - yes, for safety.
But it works no, don't it? Can it pass prime 8 h torture test?

[saxman285]

Re: Bad Capacitors or PSU Problem?

But it works no, don't it?

Well, i took the reccurance of the problem after the installation of the new PSU as a sign that the problem was still there.... so no, i dont think so. It hasnt shut down again since, but I havent had a chance to do the burnk7 and such on it yet, as i've been busy with work. If it was the PSU though, why would it have had a power cut once the new one was installed?

[trodas]

Re: Bad Capacitors or PSU Problem?

Probably because the new PSU hold the voltage cleaner and therefore it make the mobo partly operative again. In that case - recap immediatelly. New PSU can buy you time, but not too much of it.

Anyway, I would still advocate running of Prime95 as stress testing instead of burnk7

[willawake]

Re: Bad Capacitors or PSU Problem?

what caps do you have on the board anyway?
post some pics.

[saxman285]

Re: Bad Capacitors or PSU Problem?

So I ran the BurnK7 for about 10 hours with no problems, then the next day for about 18 hours and then it shut off. I feel more like it was probably just time to shut off again though, as it had been running for at least 4 days by that point without shutting off, rather than having been because of whatever the program was doing... I then ran BurnMMX the next day for at least 10 hours, also failing to cause a problem. In the days following though, it has gotten worse again, and its now shutting off AT LEAST once a day, or as was the case yesterday, 3 times within 10 mins while i tried to just boot it so i could use it.... or today once when i tried to boot it to post here.

Where can i get this Prime95 to test that?

Also, here's some pics, though they arent the clearest, and i dunno what you can deduct from them.

First pic is the caps above the CPU
Second is to the right side of the CPU, next to the RAM
Third, below the CPU
Fourth, the bottom of the board, near the PCI slots
and Fifth is just a view of the whole board...

[Tom41]

Re: Bad Capacitors or PSU Problem?

Those look like OST caps, which are known to fail under certain circumstances. However, these don't look bulged or vented yet, so are probably still good - an ESR meter would be the only way to check.

Don't forget that the caps inside PSUs can also bulge and vent, and if your board receives 'dirty' power, it can show bad cap symptoms even if the caps on the board are perfect! You may even have got a 'bad' new PSU, so don't rule that out yet - I posted pics of a Kobian Mercury PSU recently that died within 8 months of being installed!

It's not common, but it's possible for caps on a board to fail without any physical signs. Teapo are notorious for doing that, not sure about OST though.