The next Glen Ellyn CCC chat and repair meeting will be held on March
28th, 2026.
Anytime after 2PM until we all get to tired to solder and talk.
We will order Pizza around 5:30pm.
As usual Beer and Pop will be provided.
385 Saint Charles Rd
Glen Ellyn, IL 60137
+1 (773) 414-1044 (Cell)
Short version - I'm looking for copies of the PDP-8 software for the DEC
MPS, MIcroProcessor System.
Longer form, since it wasn't very well known - DEC made an 8008 (yes,
8008, not 8080) microprocessor based system on a set of three quad sized
modules, plus a really nifty looking lights and switches front panel. It's
not clear what DEC expected customers to do with it; I guess use it to build
an embedded control system for things that were too simple for a PDP-8 or
-11.
In any case, DEC made a whole software development toolchain for the MPS
and 8008 using a PDP-8 as a host computer. There was a cross assembler (aka
MPA), a downloader (aka MPL), a specialized text editor (yes, MPE), a
debugger (you guessed it - called MPD), a EPROM programmer, and several
other miscellaneous tools. They were all distributed on paper tape and I
believe they were intended to run on a basic 8/E and Teletype, without mass
storage and without OS/8.
If anybody has these, I'd love to get copies of the tape images.
Thanks,
Bob
I just came across this today, it looks like work that came about around
January 2024 by Mattis Land. Mattis, not sure if you're active here, but
this is really great work!
The emulator code is here:
https://github.com/MattisLind/DP2200/
An Unlisted demo of the emulator in action is here (running some CTOS
software):
https://www.youtube.com/watch?v=XfsMBhP13ww
Might this CTOS be the only operating system fit on an audio
cassette tape?
-Steve
Hi Ali,
I just replied to you through the vcfed forum. My posting is being moderated
(likely because I'm an infrequent poster) but I am interested in your HP
2563C printer.
Stan
I asked this before a few years ago but didn't come to a firm conclusion. The two parts are shown in this picture: https://rjarratt.wordpress.com/wp-content/uploads/2023/12/img_20231221_1123…
They are from a VT100 Monitor board. There is no schematic for my version of the board, but a related schematic is on p58 of this schematic: https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82.…. They are labelled Q414 and CR406, but the Feb 82 revision uses a different board and those two parts are in TO-220 packages rather than TO-3 as here..
I have removed both of them and tested them with a DMM. Neither of them measure as two diodes, they do not measure open circuit in any direction, so either they are both faulty or they are not transistors (unlikely). I have found a spec for a 2SB411 at https://alltransistors.com/transistor.php?transistor=10279. This seems to be a germanium transistor. When I last asked about this I had a conversation with Tony Duell, who was very sceptical that these could be germanium transistors, so naturally I am very doubtful that they are 2SB411 transistors. However, in the schematic Q414 is shown as NPN, the 2SB411 is PNP and this seems to match the way the part is connected on my board (Collector to HORIZ GND). I am working on a reverse engineered schematic.
Can anyone tell me what these components are so I can find a datasheet for them? Better still a suggested replacement would be really helpful, especially if they are 2SB411s because they seem to be hard to find.
Thanks
Rob
I find my collection of random old cards overflowing and I have picked
out six random PCI/AGP cards on the offchance anyone is interested
- Hauppauge PCI WinTV
- ES1371 AudioPIC (x 2)
- PCI Audio/modem card
- ATI AGP Rage Pro 109-73100-02
- ATI Radeon 9550 128M AGP
Images at https://postimg.cc/gallery/Y7PRkCG
Are the cards of any interest to people? (for the price of postage or
collection from London, UK :)
I may also have a phenom 9550 with its motherboard, some and a
selection of PCI plus IDE/SATA network cards - let me know if I should
go digging...
David
At 06:17 AM 2/6/2026, Christian Liendo via cctalk wrote:
>https://tinney.net/in-memoriam
>
>Robert Frank Tinney, of Washington, Louisiana, passed away peacefully
I remember meeting him at a COMDEX or maybe a West Coast Computer Fair
once upon a time. He was selling prints. I recognized him. His booth
wasn't getting the traffic it deserved!
- John
