The process of migrating the cctalk and cctech mailing lists to a new
host in Chicago is underway. This evening, I've moved the list mail
handling to the new server, and this message will be the first live
test. Assuming this works, you shouldn't have to change anything to
post to the list.
The green web pages, the old "pipermail" list archives, and web access
to archives of new postings from this point still require a little work,
which I hope to complete in the next day or two. I will eventually
import the old pipermail archives into the new posting archive, but that
may take a little longer.
The new hosting is provided by the Chicago Classic Computing group.
Many thanks to Jay West for hosting the lists for 20 years!
I am still looking for a DQ696 to allow me to get ESDI drives going on
both my microVAX and 11/73 since the Webster RQD11 controller failed I
only have the one. I'd also like to get old of an RQDX3 since I built a
Gesswein emulator and have nothing to test it with :-)
Any help appreciated,
Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
After some discussion on reddit about russian PDP-11 clones, i made the (perhaps erronous) claim that the PDP series in general was cloned by the Soviets.
I’m aware that there was a lot of QBUS/LSI PDP-11 clones, and depite poor documentation, there is significant evidence of PDP-8 clones. Also, depite not strictly a “PDP”, the VAX series was also cloned.
However, i’m curious whether anyone has any evidence of either the 18-bit or 36-bit PDP machines being cloned? I imagine that given the rather lacklustre success of the 18-bit series, that there would have been less demand for an 18-bit PDP machine in the Soviet Union, but i find it quite hard to believe that no attempt to clone the PDP-6 and PDP-10 machines would have been attempted.
Does anyone here have any information on such clones?
As the subject (and wikipedia) say:
** A C programmer asked whether computer had Buddha's nature. **
** As the answer, master did "rm -rif" on the programmer's home **
** directory. And then the C programmer became enlightened... **
** Tomasz Rola mailto:email@example.com **
Found an ad from 1984 - poor resolution but gives you an idea of what the strap looked like. -W
Date: Sun, 25 Sep 2022 16:25:59 +0100
From: Tony Duell <ard.p850ug1(a)gmail.com>
Subject: [cctalk] Fwd: Philips P2000C carrying strap
To: "General Discussion: On-Topic and Off-Topic Posts"
Content-Type: text/plain; charset="UTF-8"
Does anyone have a Philips P2000C CP/M luggable with the carrying strap?
I will be restoring such a machine in the near-ish future and mine is lacking the strap. Clear photos of the end fittings that slot into the machine, the dimensions of them, etc would be a great help in making something up.
Been a while since i have posted here. I have several PDP11 systems and
peripherals. I picked the original lot of a system 34 and related tech
in Miami FL a couple years back, and have since found several more pdp
11/34 machines, and a pdp 11/05, 11/85, and others.
It has been a goal to get the original PDP 11/34 system up and running,
however my job schedule kept getting in the way of my repair efforts,
making it easy to loose track of where i was at with the repair
progress. Thankfully i no longer work in a datacenter in a 10 hour
overnight shift, so it should be much easier to devote my time to this
I am looking for advice to get the 11/34 system up and running. I have
started to put together a site to document my progress, to stay on track
with the repair effort. The system has 2 rl02 drives, and an attached 9
track tape drive. I had worked to repair a power supply issue at first,
there was a problem with the main transformer, as well as one of the
smaller voltage "bricks". Thankfully i have many systems and i was just
able to swap in the needed working parts.
So this is about as far as I got, I had a minimal config of the 11/34
machine running, with not much more than the cpu, and a serial card to
talk to attached terminal. Power supply works, and i was able to toggle
in programs from the front panel to output characters to the attached
I believe the next logical step was to try and attach the rl02
controllers, and see if the disk packs still have working installs of
RSX installed. I am not sure how to proceed with this though.
I have mainly been following the advice of Paul Anderson, who has been a
godsend in regard to advice and guidance with getting these old systems
fixed up. I hope that if i keep a log of the repair effort on my site,
it will allow me to pick up where i leave off with the repair much more
So that is the present condition of the machine. Good power supply, can
toggle in simple programs to print to the attached terminal. Any advice
on how to proceed is much appreciated. I Need to get an itemized list
of what hardware and cards i have on hand, and post that here so its
understood what i have.
I have a box of SCSI stuff that I'm no longer using.
PCI adapters (Adaptec, Symbios)
Cables -- 68-pin, 50-pin Centos, 50-pin Mac-Centos, 50-pin ribbon
Yours in exchange for a PDF of a USPS flat-rate box shipping label.
Everthing might fit in a medium flat-rate box, but just to be sure send
a PDF for a large flat-rate box.
The H7842 PSU in my Rainbow failed yesterday. At first the machine just
powered down and there was a slight burning smell, I wasn't next to the
machine when this happened, so I didn't see or hear anything to tell me
where the problem might be. Not being sure if there was a short in the
machine or a problem in the PSU, I disconnected the fans, FDD and HDD and,
probably foolishly, I applied power again to see if the machine would work.
At this point there was a bang and a flash in the PSU.
On opening up the H7842 power supply I found that one of the transistors had
completely disintegrated. It looks to be the main switching transistor, here
is a picture of it:
have identified a source for this transistor, but if anyone can suggest a
modern replacement that would be useful too. However, that is not my main
Given that before the transistor blew up there had clearly been another
failure somewhere else, I tried to find the original failure. There were no
obviously damaged parts, so I just probed around near the transistor for any
parts that were open circuit or short circuit. I found a diode connected to
the base of the transistor that appeared to be short circuit. So, I decided
to lift one end to check it. As I de-soldered one of the leads, the diode
broke in two. So clearly the diode was either damaged by the failure of the
transistor, or it was the cause of the failure. This is the diode:
I can't quite make out the markings on the diode to know what to replace it
with. I think it says "D610". Would that be the right designation? If so,
can anyone suggest a suitable replacement please?
The diode seems to connect an inductor to the base of the switching
transistor and the collector of the transistor is connected to a
transformer. Should I be looking for other failed parts? Not sure if the
diode failed first and then caused the transistor to fail? Or if something
else has failed which caused these parts to fail?
I do know that there are no shorts in the Rainbow itself, because I have a
spare PSU that still works fine in the same machine.
I blogged this here (it repeats most of that I have said above):