Troubleshooting - RCA COSMAC Operator's Manual

Troubleshooting
After plugging the Microkit in and turning POWER on,
the POWER light should come on. It is a d.c. power
indicator (LED) and failure to light indicates a failed
or shorted supply, a burned-out indicator, or that the
cable from the Clock and Control module to the front
panel is disconnected.
Depressing RESET should cause the RUN indicator to turn
off. If it doesn't, you may have noise or extraneous.
signals present on ariy of the DMA, DMAIN, or INTERRUPT
lines.
Depressing RUN UTILITY should cause the RUN indicator
to light. If it doesn't, you may have a failure in the
Clock and Control module, no CLOCK' signal, a burned-out
indicator, or a failed CPU. If CLOCK and d.c. power
(VDD and CPU PWR) are present at the CPU moJule, then
TPA and TPB should also be present.
Hitting LF or CR after RUN UTILITY should cause VT2 to
calibrate itseTr and type out a prompting asterisk. If
the Microkit does not respond to UT2 commands, then
locating the source of trouble is beyond the scope of
this manual.
The troubleshooting of user designed interfaces is an art.
Suffice it to say that this sort of troubleshooting can
be considerably eased in the Microkit environment, because
one can easily enter short test programs.
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