A501 Company Commodore, USA   Date 1987   Amiga A500   Interface trapdoor slot   512 kB RAM rev 5 (1987) and before: sixteen 256k×1 DIPs rev 6 (1988) and after: four 256k×4 DIPs battery backed up clock rechargeable Ni-Cad battery metal shield connects to the trapdoor slot Photo front side back side Rev 6, front side Rev 6, back side Rev 6, front side Rev 6, back side Rev 5, back side Rev 5, back side