17 Jul
2012
17 Jul
'12
11:54 a.m.
If the 'Molex' connector is actually a
flat white thing with 8 possible
This one is 2 rows of 3 pins. The Berg connector is wired for EIA as described on pdp11.nl and the DL11-W's have the
driver chips so all
good there.
OK, you have 2 choices I guess. Try to find a mating plug for that
conenctor, or chop it off and conenct the wires to soemthing else. In
either case you need to trace where the wires go to, all you ned are TxD,
RxD and Ground.
Can you haldt the CPU (IIRC that's ctrl-halt
on the keypad panel),
You are right with ctrl-halt but I get the Bus Error LED rather.
My current configuration is as follows (note that the Grant cards are
all in Row D).
GRANT M9302
GRANT
GRANT
M7847 M7847 M7847
GRANT
M7847 M7847 M7847
M7859 M7859 M9301
GRANT
M7263 M7263 M7263
When I first received the machine the configuration for this 9
connector section was:
GRANT M9202
M7856 M7856 M7850
GRANT
M7847 M7847 M7847
GRANT
M7847 M7847 M7847
M7859 M7859 M9301
GRANT
M7263 M7263 M7263
so the only difference is the removal of the M7856 and replacement
with a Grant card. I will reinstate the M7856 and see it if makes any
difference.
Are yuo using the single-height grant boards (little square things) or
the dual-height ones (with handles)? If the former, check you've got them
the right way round, the traces towards the M9302 end of the backplane.
What I normally do is use a logic proble to see which grant signal is
high (yes, grants are active-high, unlike most Unibus signals) at the
M9302. Then trace that particular signal trhough all the boards. Most fo
the time it's the NPG signal because the jumper is not fitted o nthe
backplaen and I'm usin a board that doesn't use or pass through the NPG
signal.
-tony