For this memory upgrade you need an Amiga 500 with a revision 6A motherboard, and an 8372A Fat Agnus chip, plus four 256Kx4 DRAMs (81C4256A – I scavenged mine from a RAM card that had been battery leak damaged)<\/p>\n\n\n\n
When I first got this Amiga 500, I discovered that it had a 512KB Ram expansion in the trapdoor slot. The expansion had a battery backed real time clock on it. But the battery had leaked, causing damage both to the expansion card and the Amiga motherboard. (see Amiga 500 “Power Light comes on” Repair part 1<\/a>). Now, I repaired the motherboard, but the RAM card looked to be beyond repair.<\/p>\n\n\n\n But maybe all was not lost. The chips themselves looked like they could be salvaged. And the A500 motherboard has four empty chip sockets in the area labelled “512K\/1M RAM” They’re the same kind of RAM chip, so it should be possible to fit them and have 1MB on the motherboard.<\/p>\n\n\n\n Assuming I can get the chips out of the old board intact. And that they work…<\/p>\n\n\n\n Oh and there’s a bonus: the 8372A Fat Agnus chip can access 1MB of “chip” memory. All we need to do is set a jumper on the motherboard and our memory upgrade is complete.<\/p>\n\n\n\n