From wikipedia:

The keyboard LED uses blink codes where 1-blink means the keyboard ROM has a checksum error, 2-blinks means RAM failure, 3-blinks means watchdog timer failure.[11] Using caps lock key and getting a response means CIA and the CPU works.[11]

Logic dictates that it would be better to try the suspicipous chips in a working motherboard.

But then again, logic doesn't get you far in Amiga land

Wait for more answers before you try anything, please

Um.. how about you try booting the machine without the keyboard connected?

Anyway... all Amiga's should boot without a keyboard or when the keyboard is faulty. The first thing to try is to swap the CIA chips. They both control different sides of the Amiga peripherals and some internal timing.

By swapping the CIA's first you might get a different boot problem.
IF you get further into the boot sequence then begin to swap chips. It is very unusual to burn out something on the motherboard unless you have inserted parallel/serial/mouse cables while the machine is powered on.

This is a good way to fry CIA's and sometimes the logic on that port, resister or diodes etc

Az

started swapping chips, putting the "bad" chips in the "good" A500.

started at the front, till I got to the second to last chip, "odd cia"

and sure enough, the "good" board displayed the same symptom as the "bad" that is, a constantly flashing caps lock light...

so, I put all the "good" chips in the "bad" board, including the "good" odd cia chip...

no more flashing caps lock!! except, it does nothing... lol, no kickstart screen, no floppy drive trying to boot...

hrrmm...

I kinda figured the ODD CIA would have been damaged by plugging or unplugging something with the computer on, so didn't think I'd hurt it, plus I have a spare "even cia" chip anyway
 
the floppy drive was plugged in incorrectly when I first got the machine, not backwards, but 2 pins off, could this have damaged something else that will cause the computer to do nothing?

Caps lock can be turned on and off for a few seconds after turning the mother board on but then it stops responding.

That means the mainboard isn't acknowleding the KB controller's send attempts - once the internal queue fills up the LED isn't changing any more.

Amigas boot up fine w/o a keyboard.

I'd swap the chips one for one into a working machine to see if they work. Usually one of the CIAs, Gary or the CPU are fried.

yes it had a faulty odd cia, its been swapped for a known good one, ALL of the socketed chips have been.
 
the original issue that presented itself as a flashing caps lock light has gone, but the motherboard still does nothing, other than have a functional caps lock key/light for about 3 seconds.
 

could this have damaged something else that will cause the computer to do nothing?

that is, other than the socketed chips, which have all been swapped.