Those chips are 256K*1 DRAMs, so the card is a 512K memory card. My >guess is that it's a close clone of the Tandy 512K RAM card (there >were several such cards around when the CoCo 3 was in production), >and that it replaces the standard 128K RAM on the CPU board (look >for 4 empty 18 pin sockets). You therefore have a 512K machine. -tony