The number of times toggling the cap lock is related to the buffer in the keyboard. The keyboard buffer can only hold so many keystrokes before it needs to be emptied by the CPU.
So, that can only tell you that the buffer is not being emptied.
The CPU should be good because you are getting Error codes, if the CPU was bad then there will be no display and no error codes.
Maybe try to boot w/o floppy drive cable and see what happens, it may take little longer, just leave it on w/o floppy drive for a minute.
Some more behavior to report: When you power on the A500, you can press the caps lock button 12 times, and it won't respond to further presses.
If you press Ctrl+A+A you can only toggle caps lock 8 times after a reset.
Is that a pretty common cause of this issue? I want to avoid the shotgun approach if I can help it. Then again, recapping is real cheap.
I can at least say that the U2 socket looks sound. None of the pins are bent, none have oxidation or corrosion, the Agnus is held tight, the pins on the bottom are connected perfectly, and the plastic on the socket looks fine (no cracking or any funny business).
