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Freezing BIOS even - any ideas why?

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Bamse:
The bad chip you have as suspect could be a capacitor http://en.wikipedia.org/wiki/Capacitor_plague See under symptoms. Don't know if problem is always visible. Fujitsu is well known as is problem, may be a search for model name + capacitor give useful hits?

4wd:
My vote goes to the PSU - it sounds like the electrolytics are failing.

Other than that, usually when a piece of equipment won't start at switch on but will after it's had current flowing for a little while it indicates a hardware fault, (bad soldering, components gone marginal, etc), because the equipment has had a little time to warm up.

As per SJ, change the PSU first if that doesn't work then take it back to PSU, MB, RAM and CPU, see if that works then add things one at a time until it fails.

The only problem with temperature related faults is they can take a while to isolate since about the only time you can guarantee it'll happen is first thing on a cold morning, (and even then it won't if you're watching for it :) ).

EDIT: Pipped at the POST by Bamse :)

In one case, the reason for the manufacture of faulty electrolytic capacitors was industrial espionage gone wrong: several Taiwanese electrolyte manufacturers began using a stolen formula that was incomplete, and lacked ingredients needed to produce a stable capacitor.
--- End quote ---

 ;D

More likely than exploding electrolytics is that they have gone high ESRw due to aging and/or electrical ripple/spikes.  This will normally not be visible and you'd need to pull the equipment boards out and test each electrolytic capacitor with an ESR meter - not something to do if you're not electronically inclined.

Carol Haynes:
Thanks for all the advice - mostly lines I was thinking along.

The problem is dealing with a system where I can't take it away to play with (they need it everyday) and whenever I see it I can't generate the problem, although I have seen it 'post freeze'.

Capacitor pushing towards failure or dodgy PSU sound like likely culprits to me but unfortunately I haven't got a spare PSU to try it out (I suppose I could borrow one from one of my systems).

I do have a PSU tester so I could give that a whirl.

Shades:
Tantallic capacitors last a lot longer and eliminate bad spots inside themselves automatically, hardly affecting the capacity they had from the beginning.

From (jaded and mutilated) memory they are expensive to produce, really expensive to buy and not fit for very high frequencies. Then again, a PSU is not high frequency.

f0dder:
Got a client with a computer that freezes - even to the point of not allowing a forced switch off by holding the power button.-Carol Haynes (November 24, 2010, 02:03 PM)
--- End quote ---
Wow, don't think I've ever seen that before, even with pretty fubar boxes O_o

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