I have removed a PCATS memory expansion board twice. The first time, this was accomplished without damage to the underlying pads on the Empeg; the second time (same unit) was not so lucky -- messed up several pads, but was able to repair the traces with patch wires -- precludes any future attempts to reinstall the PCATS board, though.

I would leave it as is, or possibly see if any of the other banks on the expansion are usable, by rerouting the RAS lines to try each bank in turn on RAS1. But that could add up to quite a few more hours of effort.

Cheers