4 Nov
1998
4 Nov
'98
7:18 a.m.
Hi, Kevin.
On Nov 3, 21:46, Kevin McQuiggin wrote:
I have an 11/03L carcass and am hoping to use the
backplane for a set of
11/73 boards I've acquired for a friend.
I need info on the power supply, hopefully a print set, or in the least
some info on the pinout of the 10 conductor ribbon cable that runs from
the
supply to the front panel. My machine has _no_ front
panel!
The front panel pin numbers match the PSU numbering at the other end, so as
long as you can identify pin 1, here are the connections for a real 11/03
panel:
1 BPOK H
2 BEVENT L
3 SRUN L
4 not used/not connected on the front panel
5 GND
6 GND
7 +5V
8 SPARE
9 BHALT L
10 BDCOK H
On a real 11/03 panel, SPARE is connected to one end of a 220-ohm resistor;
the other end of that resistor is connected to the cathode position of an
LED position -- the LED isn't actually fitted -- and the anode of the LED
is connected to the +5V line.
The other signals are connected to a small circuit containing bus buffers
and some inverters to drive 2 LEDs (POWER OK and RUN) and be driven by two
toggle-switches (AUX ON grounds the BEVENT line and RUN/HALT is connected
via a bus buffer to BHALT L) and a momentary changeover switch (which feeds
a pair of monostables to regulate the pulse width, which then drives BDCOK
H).
I want to determine which lines are the (presumably)
DC OK, HALT,
RESTART,
etc, so that I can install the 11/73 gear and control
the system.
See above.
Secondly, the +12 VDC line from the supply is sitting
at 9.5V, no load.
There may be a problem, I can fix it but the print set would be most
helpful.
Yes, that's definitely a fault, though you should test it under load and
look at the BDCOK signal from the PSU. Sorry, I only have diagrams for
H876 and H780; the H8761 is a switch mode (as is the 786) but fairly
different, I think. Anyway, sending a copy of the print set over the
Atlantic might be slow and expensive :-)
BTW, a 7861 is not original equipment for any 11/03, it came off an 11/73S
or 11/23plus. Perhaps you have a 22-bit backplane as well? What's the
backplane H-number?
--
Pete Peter Turnbull
Dept. of Computer Science
University of York