I have an older computer with an AT motherboard. When I power it on, the AT KB line doesn't receive the proper voltage for the keyboard's 3 LEDs to turn on and off. The POST reports that was a keyboard error or keyboard is not present. I've tried 4 different keyboards, all of which work on other computers and none work on this machine. I tried plugging a keyboard into the PS/2 mouse port on the motherboard and it doesn't receive any power either. Another strange thing is that when I plug a fan into the fan connector right below the PS/2 and AT_KB connectors, the positive and common power pins seem to be reversed and on the opposite side of the 3-pin connector and the current is 5 V instead of 12 V. The motherboard has no missing resistors or capacitors so I don't think it has anything to do with the power plane of the motherboard.
Somebody please help!
Somebody please help!
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