15 Dec
2014
15 Dec
'14
10:47 a.m.
From: John Rollins
it doesn't appear to transmit data from the
console port on the back. I
have tried ... every conceivable switch setting on the PDP with nothing
...
So when I power up, the LED display on the front counts down through
the numbers and stops at 4. As near as I can tell, this is something of a
good sign.
Should be; my User's+Maint Guide says that means "Dialog Mode: Waiting for
input".
Short of spending an entire day disassembling half the
machine and
tracing every wire hoping to find something out of place, does anyone
have any ideas on what may be happening here, or what to look for?
I asssume you've tried setting the baud rate with the switches on the CPU
card (in case the cable to the back panel is damaged - or, more likely, the
rotary baud select switch has a bad contact due to corrosion over time)?
If you have the parts, fabricating a substitute serial interface cable would
also be something to try.
The next step would normally be to disable the on-board serial interface, and
provide a substitute console interface, out on the bus. _Alas_, as far as I
can tell from reading the KDB11-B User's Guide (EK-KDJ1B-UG-001), there is no
way to disable the on-board serial interface.
AFAIK, the prints for the 11/84 (MP-02536/MP-01955) don't seem to be online.
I can't locate prints for the 11/83 (uses the same CPU board, I think)
either. So I can't check to make sure that it is in fact impossible to
disable the on-board serial interface.
And the other next step, to look at the serial output and see if it looks OK,
will be a little tricky without prints, although the KDB11-B User's Guide
does contain something about it, on pp. 5-38 to 5-41 (165-168 of the PDF).
Noel