Amiga 500 boot problem

[nivalis]

I am working on an A500 rev 6A, which had a bad fat agnus plcc socket. I changed it and got to the kickstart screen.
But she will not boot, I tried with Kick 3.1, will not boot from known good df0: or df1:
The floppy reads 2-3 "clicks" then returns to kickstart 3.1 screen.
I can get into the early startup menu, and everything looks okay.

The dialogica diagnose rom in place of kickstart crashes at different places, with garbled graphics.
Sometimes at the initial tests of memory and such, but other times it crashes right away.

I swapped CIA odd and even, same result.

I guess next step will be checking continuity on the CIA pins, in case of a broken trace.
This is a defected motherboard i have had lying around for several years, so it might have gotten damaged.

But i thought I should ask here, in case there is something obvious I can't see.

 

[nivalis]

Well I Opened up another A500 and started swapping out custom chips. Paula caused the diagnostic rom to crash, so now I can run the tests.
Floppy still does not work. Diag rom says internal drive is not detected. Known working CIAs and Gary.

 

[Arnie]

Have you tried swapping the floppy drive from the 'other' A500?

 

[nivalis]

I was about to say that I am using known good drives, but I figured what the hell and removed the drive from the other a500, and that was it.. I am not sure why both my internal and external spare drive is not working, but anyway, thanks for making me check