21MX/E FAB

[J. David Bryan]

On Sunday, February 22, 2015 at 13:47, Jay West wrote:

> In pouring over the documentation for the 13304A (FAB), I find one
> thing unclear. Is there a way to disable a given block? 

Looking at the schematic in the ERD (92851-90001 March 1981), the only non-
intrusive way to disable a populated block is to ground the "pivot" of one 
of the address jumpers for the block (i.e., the socket where the jumper 
pivots for selecting 1 or 0).  Leaving the jumpers out will, unfortunately, 
enable the ROM bank always (rather than disable the bank always).

                                      -- Dave