26 Apr
2015
26 Apr
'15
10:58 a.m.
Got the following e-mail in my inbox from a listmember who apparently
wasn't able to get his mails to show up on the list:
John,
my post on classiccmp is not appearing on the list, so here a direct
mail:
...
And sure enough, I flipped the cable around and things are much happier,
the front panel is completely responsive and the CPU and bus seem to be
working but I'll need to spend some more time with it to test stuff out.
That'll learn me to trust Pin-1 markings on DEC stuff :).
Thanks all for the suggestions, it's all been very educational...
- Josh
So at this point all voltages are spot-on, the AC
LO and DC LO signals
are high (these are active low, right?) but I can't get the machine to
respond at all -- the "DC ON" and "RUN" lights are lit up brightly,
and
the "SR DISP," "BUS ERR," and "MAINT" lights are glowing
dimly. The
status register display is dark. The system does not respond to any
keypresses on the panel.
All LEDs "glowing dark"?
I've seen this, when the 20 pin cable from M7859 to the console panel
is plugged in reversed.
Don't trust the marked pin 1 wire: sometimes DEC manufacturing twisted
the cables.
hope this helps,
Joerg