Tip for bios reset / cmos reset problems

kentsmithnz

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Apr 3, 2007
4
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18,510
I screwed my overclock settings and my board wouldn't boot. Went to reset the CMOS memory but it wouldn't.

I shorted the battery jumper pins, no success. I removed the power cable, removed the battery, drained the caps by holding down the power button, left for 20 mins - no success.

Figured something must have died somehow. I systematically removed all the drives/cards/case connectors, video card, single memory DIMM. Same symptoms. Was looking like processor, board or PSU problem.

Finally figured it out - POWERED USB HUB! My keyboard is connected by a powered USB hub and must have been supplying current to the CMOS memory. I can replicate the problem by appying crap settings to make it fail, when I unplug the USB hub, short the battery jumper pins, it resets. If I don't unplug the USB, it doesnt.

FYI - this is a Gigabyte GA-965P-DS4 v3.3

Tip for the unwary :)


-KENT