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Thread ID: 110266 2010-06-10 00:47:00 PC locks up at random intervals Tony (4941) Press F1
Post ID Timestamp Content User
1108636 2010-06-11 01:38:00 Can you see any capacitors on the mainboard that are leaking, blown tops etc?What about these? Tony (4941)
1108637 2010-06-11 01:40:00 Yep. Very suss. Sweep (90)
1108638 2010-06-11 01:51:00 Yep. Very suss.Well, I can see at least 7 that look like that - so how come the thing works at all? I'm not a hardware person at all at that level. Tony (4941)
1108639 2010-06-11 01:56:00 I had a M/B that had similar problems once. Don't ask me how it was working for as long as it did as I don't know.

Others may give you a better idea about that.

I can say that there are definitely bad caps though.
Sweep (90)
1108640 2010-06-11 02:21:00 They are bulging quite noticeably and leaking.
Will you replace the M/B or attempt to replace the capacitors?
tricky but can be done
http://www.badcaps.net/
KarameaDave (15222)
1108641 2010-06-11 02:24:00 As the mobo is about 8 years old, I shouldn't be too surprised, I suppose...

I'll replace the mobo. The new version of WHS has a much higher hardware requirement, so I was going to have to do something at some time, anyway. It'll be just sooner rather than later.
Tony (4941)
1108642 2010-06-11 02:40:00 Well, I can see at least 7 that look like that - so how come the thing works at all? I'm not a hardware person at all at that level.

The capacitors filter the noise\ripple out of the power going to the CPU etc. Without them working properly the power is still there but it's not clean.

Random spikes and variations in the power supply cause the CPU etc to lock up because they require clean power. Most of the time the power is good enough but the random glitches cause the problems.

If the board still works at all depends on the condition of the capacitors and the design of the VRM circuitry.


I would check the PSU also. It's not impossible for a PSU with failed capacitors to supply 'dirty' power to the board which causes failure of the motherboard capacitors - which would happen again if you use the same PSU on a new board. Worth checking out to make sure this was not the cause.
Agent_24 (57)
1108643 2010-06-11 02:49:00 I would check the PSU also. It's not impossible for a PSU with failed capacitors to supply 'dirty' power to the board which causes failure of the motherboard capacitors - which would happen again if you use the same PSU on a new board. Worth checking out to make sure this was not the cause.So I just open the PSU box and see if anything looks like the picture? Any gotchas I need to look out for (like stuff that can still zap me even though it is disconnected from the power?) Tony (4941)
1108644 2010-06-11 02:54:00 I've also just found out that I can't boot from my 3.5 floppy. It is in the boot sequence, and I've tried it with two different drives. Could that be linked to all this stuff? Tony (4941)
1108645 2010-06-11 02:56:00 Normally PSUs have residual voltage and can still zap you. Leave the wall current plugged in shut down the PC and then use the switch on the PSU to turn power off. Remove power from the wall. Then try to start the PC. You will see the CPU fan start. It won't boot but where did the power come from. Sweep (90)
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