28 May
2012
28 May
'12
8:16 p.m.
Further testing tonight. When the deposit switch is toggled, it does increment the
address. I have verified that the processor can write to memory, by toggling in a program
with a known good control board, then swapping in the bad one and running the program. I
have also verified (with a logic probe and creative cabling) that the basic switch logic
(consisting of a couple of flip flops and a 7400) does appear to be working (chips
E97-99).
It would seem that the actual switch register/buffer is located on the data path board, so
it's not a problem with that itself.
-Ian