23 Jan
2003
23 Jan
'03
2:52 p.m.
Bill,
Something about the 16FDC doesn't play nice with
the IMSAI front panel.
You can't deposit or examine memory with it on the bus. Even with the
schematics, I don't see what the problem is. Do you know a solution by
any chance?
Assuming that you have verified that the front panel works correctly by
removing the 16FDC (and only the 16FDC), then the first thing that I
would check is to see if the 16FDC is grounding pin 20 (UNPROT)
of the s-100 bus.
If it is, a quick glance at the Imsai panel schematic will show that all of
the flip-flops and monostable multivibrators associated with the Examine
and Deposit functions will be disabled. The 'J' input of the flip-flops
need to be high, and the 'CLR' pin on the mono-multis need to be high
in order for the these specific panel functions to work.
Best regards,
Scott