3 of the 5 capacitors on the 3640 have the polarity reversed because the silkscreening on the PCB is wrong - those are probably your bad ones.
I started a thread on this last month - there might be some good details and links in there as well.
I didn't trust my soldering skills, so I had Amiga Center correct it for me. Still waiting on the postal service to deliver the thing, though!
