Checking my bible...
M8719 Unibus to D-Bus cable (I/O Daisy chain bus) control and
interface.
Where used = IP112
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | email: gentry at zk3.dec.com (work) |
| Unix Support Engineering Group | mbg at world.std.com (home) |
| Hewlett Packard | (s/ at /@/) |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 (DEC '77-'98) | required." - mbg KB1FCA |
+--------------------------------+-------------------------------------+
p.s. Looks like another one to make sure I include in the update
to the field guide, which I'm working on...
Thanks all for the many good replies.
This is what I have done so far.
At the end is what I did *not* do (yet).
At first, I kept the 3 MASSBUS interfaces installed. They were in
the machine, so I did not suspect them.
- I installed the H744 in the upper PSU.
All +5, -15 and +15 V. all look OK, measured with a Fluke. I am not
yet in the stage to pull out the scope and do "difficult" things.
- I will check the jumper on the M8132. Normally I make notes of steps
I do on my machines, but Murphy is still alive. I cleaned the 11/70
with remote console *completely*. Got the 11/70 with full console
2 weeks later. Since I am keeping one and donate the other 11/70 to
a museum, I did not want to clean the second 11/70 also. The guy at
the museum may do his share of this bargain. So I swapped the consoles,
and (AFAIK) the boards. That is the problem: I can not remember that
last action. Perhaps I did not swap all CPU boards between the 2
machines and only moved the FP option boards (and forgot/didn't know
about the H744 to supply +5V to slots 2-3-4-5).
As Tom wrote, the 11/40 indeed needs on 2 boards (IIRC) change of
jumpers for FIS/EIS (or was it MMU)?
- I kept a G727 in the 4th MASSBUS slot at the correct position.
Removed from all not used UNIBUS slots the G727 and replaced them
with G7273 dual-height grant cards.
Result is still NOK: hung on console address access (read/write).
- Removed the other 3 MASSBUS interfaces. Put a G727 instead of the
M8153, according to FMPS. Hung remains.
- The "golden" tip from Tony. Removed the M9302.
No more hung! XBUF status shows octal 200 (indicating TX buffer
empty, ready to receive byte to transmit). Store octal 71 in the
TX buffer and a "9" appears on the VT320!!
Basically, I have a complete working machine, but ...
- Put an M930 as terminator in the 11/70. Still all is fine.
- Put an onther M9302 (from the working 11/34C) in the 11/70.
The hung is back.
- Put the M930 back in again.
LOADed address 17765744 (from the M9312 manual) and pressed START.
All LEDs flicker for a few seconds, then all go off, except ADDRESS
LED #2, so address 00000004. I guess this is a TRAP because the
boot device was not accessible. Makes sense, there are no devices
connected!
What I did not do.
- Remove the RX11 (non-DMA) RX01 interface and replace it with an
RX211 (DMA) RX02 interface to see how that affects the NPR line.
- Did not check the ACLO and DCLO signals.
Since I can run "a small program", memory interconnections, the
memory and the CPU itself have no apparent problem.
- Did not try to read the ROM on the M9312 with the M9302 installed.
Will do that this evening (probably). The weekend was shorter than
I expected it to be. As usual ...
I did read the CPU registers (IIRC), but check on that again.
- I will read the M9312 manual again. The numbers Johnny writes about
sound familiar. However, it this moment I do not have any disks
(RX,RL) connected.
Thanks again so far,
- Henk.
I have a bounty outstanding for the following:
Early 1990s data sheet for the HP HCPL-7800 Isolation Amplifier
Government Microcircuit Applications Conference (GOMAC) Proceedings for
1986 & 1990
If you have these, please contact me directly <sellam(a)vintage.org>.
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
Hello,
is it possible to use an EMulex QD32 Controller (Qbus) with a PDP11/23 ?
I asked a friend and he told me that the bandwith of the bus could be
drifferent.
Is it right ?
Greetings
Pierre
--
GMX - Die Kommunikationsplattform im Internet.
http://www.gmx.net
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On Jul 15, 9:16, Tom Uban wrote:
> Hi Dave,
>
> Another solution, which I haven't tried yet is to remove the CRT from
it's
> electronics
> and soak the face in a bath of acetone for an extended period of time (or
> until the
> secondary lens is separated from the tube. Once separated, clean and
reattach
> using optic cement. This was suggested by a friend who repairs large
antique
> camera lenses. I'm not sure if acetone will dissolve the cement which
holds the
> lens to the tube, so a pre-test may be a good idea.
If the substance bonding the front glass to the the CRT is some sort of RTV
silicone compound, you might be able to remove it with silicone sealant
remover. I don't know exactly what's in that stuff, but plumbers use it to
remove old silicone sealant from shower panels, tiles, and fittings. You
might be able to get it from a plumbers' supplier.
--
Pete Peter Turnbull
Network Manager
University of York
On Jul 15, 10:14, Gooijen H wrote:
> - The "golden" tip from Tony. Removed the M9302.
> No more hung! XBUF status shows octal 200 (indicating TX buffer
> empty, ready to receive byte to transmit). Store octal 71 in the
> TX buffer and a "9" appears on the VT320!!
> Basically, I have a complete working machine, but ...
> - Put an M930 as terminator in the 11/70. Still all is fine.
> - Put an onther M9302 (from the working 11/34C) in the 11/70.
> The hung is back.
I got caught by that exact same thing a few months ago, and once again it
was Tony who reminded me of what I once knew: the 9302 makes it hang if the
grant chain is broken. I was tidying up an 11/34 which I was trading to a
friend, moved some boards, forgot an NPR jumper, and spent two days trying
to figure out why the RUN light came on and I couldn't HALT the CPU.
--
Pete Peter Turnbull
Network Manager
University of York
>From: "John Honniball" <coredump(a)gifford.co.uk>
>
>Jim Battle wrote:
>> Anyway, I found and fixed the first problem: one of the satellite circuit
>> boards on the persci had a tantalum cap that had a dead short, taking out
>> the whole +24V power supply...
>
>Yes, that's a typical failure mode for tantalums!
>
>> Secondly, I haven't done board-level design in more than 10 years, but from
>> what I recall, 99 times out of 100 when I thought I had tracked down a bug
>> to a back chip, it was something else (then again, that was during design,
>> not just working on ostensibly correctly designed boards).
>
>Until recently, I'd have blamed something other than a 74 logic chip
>just going bad. However, I've seen a few chips do just that in RL01
>disk drives, which must be about the same age as your chips (late
>1970s.)
>
>So, I'd say it's possible that the 74123 has just ceased to function
>"all by itself". Due to age, that is, not due to external factors.
>In the end though, it's up to you to decide whether you suspect chip
>failure enough to warrant replacing it (with all the associated taking
>apart, soldering and putting together again).
>
Hi
The capacitors used with 74123's tend to fail over time
because they are slightly back biased at the of the discharge
part of the cycle. This does in tantalums and electrolytics,
over time. Non-polar parts are usually OK.
Dwight
