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mainboard dead?

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by rr0s3 Feb 25, 2003 last reply Feb 25, 2003

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i have a white-box pc i've been asked to look at. started having trouble booting couple of weeks ago.

i first looked at the power supply and swapped it with no results. not even the fan in the new power supply would turn. so, i started unplugging cards and cables to start through them one-by-one to see if i could isolate the problem.

with nothing in the board except for the processor, the cpu fan and the memory, the power supply fan now comes on, i get leds at the front panel and the cpu fan tries to start (does about 1/4-turn and stops).

when i plug in the nic, video card, floppy and cd-rom, i get the same result. the power supply fan spins and i get leds at the front panel. however, when i plug-in the hdd, the system doesn't power up. so, i replace the hdd.

now i've got a new power supply, a new hdd and i've verified the other 2 cards, but it STILL won't boot.

when i plug it all together and power on the supply (NOT THE MAIN CPU POWER SWITCH, but the power supply switch at the back), i get everything on before i even hit the 'power button'. BUT, there are no beeps from the bios and there is no activity on the monitor, it stays black with an amber ready light.

9 replies

by cg it Feb 25, 2003

working backwards taking out individual hardware components one at a time to isolate the problem seems to be the best approach. Try swapping out the processor with a known good one and try that. Mainboards do go bad but could be the processor.

Note: Antec makes a $16.00 power supply tester which is well worth the investment if you regularly troubleshoot or repair computer others hardware.

by rr0s3 Feb 25, 2003

checking the processor to make sure it's ok, but it seems to be. i think it's the mainboard....

by hinrgman Feb 25, 2003

what make PC?? MotherBoard etc.....

by rr0s3 Feb 25, 2003

if you note, i stated it's a white-box pc. custom built... the board is an intel desktop board.

by thechas Feb 25, 2003

If you spin the CPU fan by hand, does it spin freely, or stop within a turn or 2?

If the fan stops, it is likely that the fan died a while ago, and now the CPU is fried from over-heating.

In case there is a problem with the motherboard, swap in the cheapest CPU of the correct family that you can find.

If it still does not work, look at the motherboard closely.
You are looking for signs of overheated, or bulged components.
If you see any parts that are charred, bulged, or the solder has flowed, and the part is off of it's solder pads, the voltage regulator on the motherboard has failed.
This often happens when a lightning strike comes into the PC through the modem.

Chas