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PC half dead - not good Answered

Machine will not POST - no beep, BIOS smart fan-control not engaging, PS2 keyboard has no power, monitor reads "no signal"
Board does have power - things spin (like the CPU fan which shouldn't until it gets hot)

Preceding clues(?) -
I thought I'd developed tinnitus, but found it was the PSU (I think) making a high-pitched ringing noise, half the day unplugged and that seemed to go away.
Display not engaging properly on start-up: If I waited until the machine got to Windows login and then switch the monitor on - no problem. Switching the monitor on before this point - black sort of standby mode.

I think I might try the PSU first, then think about the mainboard. So far I've plugeed and re-plugged things, tried with 0,1 & 2 strips of RAM with no difference.

Any suggestions welcome

I spent a lot of time replacing 1 cap' in the PSU, then I replaced the PSU (logic being that if I've tampered with it an the thing still doesn't work I should replace it regardless)
Then I bought a new board. I was a bloody-sod, CD/DVD still doesn't work...




.  I'd try a known good PSU first. If you need a new mobo, you might as well get a new computer.

Yea, but a new board would be cheaper and I wouldn't have the bits that work to dispose of...

I'll see


 I have a BOX of old PSU's, come get one, they're cheap even for a new 500 watt...

I have a spare now so I'm OK, thanks.


i was given a computer for free with similar problems to this and it ended up being a faulty capacitor on the motherboard. i replaced and it was as good as new.

hope this helps

It didn't help my situation, but I appreciate the comment.


hmmmmm. maybe something has shorted and burnt one of the rails on the motherboard.

Faulty capacitor probably making the noise. You could try to track it down and replace it, or... New motherboard.

That's what I was thinking (both comments)


.  Your mention of bad caps reminds me of the spate of bad mobo caps. Looking at the common name - pregnant caps - you can guess that they are usually easy to spot.
.  If you are unsure of your soldering skills on a multilayer PCB, you should be able to find a local hobbyist that will do the job for a cheap meal and a beer.