Help Identifying mods
 

I have recently gotten hold of an Amiga 500 (PAL rev:6a) it it seems to already have a few mods that I cant identify.

The first is a switch that goes to a riser board under the Even CIA

The second seems to be JP3 solder bridged.

the one mod I can id is ram sockets installed, but what RamChips can I put in and is the a mod need to use the extra ram (is this fast or chip ram)

The CIA mod is probably a boot selector.

JP3 has been modified and then bridged back into normal orientation. Either someone was debugging a RAM issue, or this board might have had a reslow circuit installed in the past to enable the trapdoor RAM separately from the soldered-in sockets on the motherboard.

The RAM chips are the same kind as the ones already in there. 4x256k. Whether it is Chip or Fast depends on JP2 and JP7.