MITS 16K Static RAM board (88-16MCS)

Mapping an address and bit failure to a particular RAM chip.

The 16K board uses 4K x 1 bit RAM chips (4200). Each vertical column of chips on the board (columns A, B, C, and D) are 4K x 8 with one chip per bit. Bit 7 is in the RAM chip at the top of the board and bit zero is in the RAM chip at the bottom of the board. Columns A, B, C, and D correspond to the 1st, 2nd, 3rd, and 4th 4K block on the board (A13, A12 of 00, 01, 10, 11 respectively).

Given an address and bit number that has failed, a particular chip can be isolated.