Can anybody advise on a power up problem? PC tries to power up, pwr unit fan spins for 1 - 3 seconds, no mb or POST beeps, LED on HD flickers, then system switches off. Suspect the power supply, but changed it with a known working one, same symptoms.

Suggested diagnosis or fault finding?

System is:
Intel 440LX motherboard 233Mhz

rgds
PM.

Sounds like either bad voltage (voltage drops to an unacceptable level with the extra load or fluctuates regardless of the load - not likely if you live in a home built in the last 30 years or so...unless the power company's transformer is going bad...but I digress http://www.PCGuide.com/ubb/smile.gif ) OR you've got a failing motherboard.

This prolly goes without saying, but if the mobo is form factor AT, don't forget the black wires from the power supply go in the middle.

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If my computer were the eighth dwarf, it would be Dumpy.
-Chris

I respectfully disagree! It sounds a lot more like a short or incorrect jumper setting would need to be checked before thinking about the motherboard being bad. If it were me, I would double check the jumper settings for the cpu [DONT overclock!]and then check to be certain all PCI cards were seated correctly as well as the AGP video card, if present. I've seen incorrectly installed PCI cards AND RAM improperly installed cause these exact same symptoms.

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XP didn't save Me !

Dont know if this helps, but I had a retaining clip that holds the spring come off of my power switch. When I pushed the start button, it never sprung back out and the computer would shut off after about 3 sec. By taking the front panel off and pushing the button and the gently pulling it back out, the computer would keep running. Fixing the clip and spring eliminated the problem.

Just an idea

My reasoning and response were based on the assumption that since it's an older system, it's prolly been in use for a while and this is a newly manifested problem (in other words, not likely to be jumper settings). The installed RAM and PCI cards shouldn't come unseated easily. But again, we're talking about an older system here, and anything's possible over time.

Thanks for correcting me with respect, Randy_tx. http://www.PCGuide.com/ubb/smile.gif

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If my computer were the eighth dwarf, it would be Dumpy.
-Chris

Thanks for all the advice - Found it.... microswitch behind the power button has shifted. Enough to signal a power up, but not enough to keep the system running.

thx matpoh

http://www.PCGuide.com/ubb/smile.gif PM.