Bad Caps.

Well bad caps are still alive & well.

My machine just decided not to start up last night.

Two caps in the memory PSU circuits had decided to give up the ghost. Both were bulging and one was actually leaking gunge. I have replaced both and the machine is back up and running.

For those who want to know, the machine is a Packard Hell Pentium D 3000 dual core. Fitted with an ASR Prescott 800 mainboard.

The main CPU PSU caps are very hot 81C measured temperature. I'm wondering, should I replace them as well? The two toroid coils on either side and the vertical Choke at the rear are running well over

95C. Is/could this be normal for these components?

Comments !

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Regards:
              Baron.
Reply to
Baron
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Make sure that the caps are 105C rated - probably normal. OTOH, they do have a lifetime - how old is this machine? Might not be a bad idea to just replace them with new 105C parts and be sure.

I have at least two, and perhaps 4 (not as obvious what's wrong with the second pair) of Apple eMacs with bad capacitors, which had one of those irritating secret repair extensions - which expired before I figured out what the problem was and discovered the not-very-well publicized repair extension (the ones with clearly bad capacitors start up, but freeze - in the early stages this was infrequent enough that it was not obvious why - only one of the bad capacitors is visible until the case is opened up, and the other 7 come to light). Just barely over 3 years old. In this pair, the affected capacitors are all the same size/voltage/brand, and none of the others appear to be affected.

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Cats, coffee, chocolate...vices to live by
Reply to
Ecnerwal

Yes I did look, they are marked 105C 3300Uf @ 6.3 volts. The machine itself is about two years old, possibly 3 to 6 months older depending how long it was in stock before I bought it.

I have had machines that have done that, random freezes and spontainous reboots. In every case its been down to the electrolytic capacitors. I've only had one machine where the caps were fine! That machine suddenly destroyed itself, CPU, RAM, Video Card the lot. I never did get to find out the real cause. That was an Emachines 2210. Biggest load of crap I have ever installed Linux on!

I'll order some new caps anyway. Just in case. By the way I just rechecked the cap and coil temperatures they haven't altered in the past four hours.

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Regards:
              Baron.
Reply to
Baron

Emachines used to have a power supply that would output high voltages just before it crapped out. As I recall, it was a 250W Bestec unit.

David

Reply to
David Snowdon

Yes David, you are right, the PSU was a 250W Bestec and it had packed up. Dead as the proverbial Dodo it was. Oddly the internal fuse wasn't blown.

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Regards:
              Baron.
Reply to
Baron

Is this Electrolytic Capacitor? Caps are supposed to be COOL, NOT Hot, if you continue to let it go like that it will blow up and then you won't have a clean power. Your electronic components will fry after that. Very likely the cap must be rated lower than it's supposed to handle, or you must have more AC power coming into the unit.

Jack.

Reply to
Jakthehammer

Have you ever tried putting your fingers on the CPU PSU caps in your computer ? Don't burn your fingers !

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Best Regards:
                     Baron.
Reply to
Baron

Yes I had, and Have you ever seen caps blowing up in front of your face?

Reply to
Jakthehammer

Yep! two serial caps,250volts apiece, accidentally connected in reverse to 500 volts. They exploded nicely, spraying electrolyte all over the place.(and in my face).

Reply to
Sjouke Burry

Good for you and for me, this way we learned the hard way. My incidents were happening 30-yrs ago, 3000-5000Volts, 0.7amp. That made me a funny guy today....Heehee........Donchaknow?.............

Reply to
Jakthehammer

I was being serious here. Under normal conditions they will run hot!

Yes ! But what do you think the markings are in the top ? They are there to prevent that kind of destructive behaviour. Caps do run hot under certain conditions unless someone has found a way to reduce ESR to zero.

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Regards:
              Baron.
Reply to
Baron

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