test-drb May 2021

test-drb@ccmp.vtda.org

128 participants
102 discussions

That VAXStation4000vlc 3W3 video connector

by athornton＠gmail.com

I assume it would be way too much to hope that HD BNC would fit it? Does anyone have a pointer to the actual physical dimensions of the itty-bitty BNC-ish connector in the video port of the VAXStation4000vlc? If I can get red, green, and blue out (assuming since there are only 3 connectors it's sync-on-green) I can put together a sync splitter and turn it into VGA. I have at least one decent multisync VGA monitor still, although none with the RGB BNC inputs. Adam

2 years, 12 months

IBM 1410 FPGA Implementation Update - new github repository

by michael.99.thompson＠gmail.com

> > Date: Sun, 2 May 2021 15:38:33 -0500 > From: Jay Jaeger <cube1 at charter.net> > Subject: IBM 1410 FPGA Implementation Update - new github repository > Message-ID: <68c06711-e563-f1bf-8abc-090793bed752 at charter.net> > > The last 12 months I have been pretty busy working on my 1410 in FPGA > project, and there is now more to share, though I have not done much > actual work since February - been too busy playing with other "toys". 8D > > JRJ > The RICM has a 1401 control panel. It would be pretty cool to mount your FPGA to the back of it and get it to blink the lights the right way. https://www.ricomputermuseum.org/Home/interesting_computer_items/ibm-contro… -- Michael Thompson

2 years, 12 months

920M - and also the Argus 200 / 700

by erik＠baigar.de

Hi Jos! > in the UK around 1960 the Argus 200 was developed to control the Bristol > Bloodhound anti-aircraft rocket. This computer was one of the very first > transistor-based control computers. Absolutely - in these days Ferranti and Elliott where competitors on the European market for defecne computing! Very funny, that they later merged and today the legacy of both is distributed in the BAe and Leonardo businesses ;-) There are quite interesting stories, on occasions when the two had to cooperate before merging and in the ELDO project mentioned in my video, the computer was from Elliotts whereas the inertial sensor was from Ferranti (https://youtu.be/v-gF5g0nnoE?t=363). > In Switzerland the Bloodhound was on duty?? until 1999 ! One of the sites, > once top secret,?? is now a museum, and well worth a visit. > Check out https://www.museums.ch/org/de/Bloodhound-Lenkwaffenstellung Definitively worth a visit! I am also into the Ferranti navigation systems >from the 1970ties (https://www.youtube.com/watch?v=-EQqfxiGgd8) and since years I am trying to find out, what architecture its 32 bit computer is. Here I booked an extensive special tour and the team on mount Gubel organized some experts to join the tour - although I learned that the INS computer is not related to the Argus series, the visit was AMAZING! Also great there to see the technology of the almost Mach3 missile from the 1950ties. Erik.

2 years, 12 months

RS64 on a PDP-8?

by jnc＠mercury.lcs.mit.edu

Is there a controller to attach an RS64 disk to a PDP-8? The only controller for the RS64I can find is the UNIBUS RC11. Thanks. Noel

2 years, 12 months

Cipher C995 manuals

by drb＠msu.edu

I have a recalcitrant Cipher C995 9track drive. Does anyone have manuals for this thing? It seems to be enough different from the M990 to matter. Thanks, De

2 years, 12 months

Sprague 2X.1-1000 filter capacitors and 854-B power control assembly

by ccth6600＠gmail.com

Unfortunately once again I am having trouble with Sprague 2X.1-1000 filter capacitors. The two filter caps on a Lab-8/e rack's 854-B power control assembly appear to occasionally leak to ground more than the 30 mA tolerated by my RCD. Mostly it trips the RCD when I power off the system, but sometimes it even trips the RCD with the system powered off. One of the two filter caps is permanently connected across mains power and earth coming from the cable (i.e. it is before the power switch). The exact same filter caps were also used inside the LAB-8/e computer?s power supply. Early on I replaced these with a small PCB with a bunch of male spade connectors and two Y class safety caps. The PCB was designed to replace two of the Sprague filter caps in the side-by-side configuration used inside the LAB-8/e?s power supply where it is also hidden from view. The PCB was designed by Malcolm Macleod in Melbourne/Australia who hit the same problem. I got the PCB manufactured in China from his design. The 854-B power control assembly has the two Sprague filter caps sitting on either end of the assembly ? far from each other. Also the can of the capacitors is exposed at the back and clearly visible so even a newly designed PCB with a single set of safety caps wouldn?t look great and also wouldn?t be stable because there are only two mounting holes. I cannot think of a neat solution to resolve this. I could try to find an electrician willing to wire me a non-RCD protected socket into my study, but I can?t quite warm to that idea. The RCD is an important safety feature. By law now all houses are required to have their AC wiring protected by 30 mA RCD circuit breakers so I likely would have to do this myself. The other option would be to make or buy two terminal blocks with male spade connectors and connect the female spade connectors to those rather than the Sprague connectors. I could then also wire in the 2 Y class safety caps or even forego the filtering. It would mean drilling new holes into the power control assembly. Chuck(G) in the vcfed DEC forum suggested pulling apart the old "bathtub" capacitors and replacing their guts with modern safety caps. The caps contain toxic and carcinogenic PCBs so I am less than enthusiastic about that idea. The capacitor's metal can is soldered together so trying to desolder it would heat the mineral oil containing the PCBs which would make them even more harmful. There is no point in trying to hunt for ?new? Sprague 2X.1-1000 because they would all be ancient and have the same leakage problem. Any thoughts, ideas or suggestions? Best regards Tom Hunter

2 years, 12 months

IBM 1410 FPGA Implementation Update - new github repository

by cube1＠charter.net

The last 12 months I have been pretty busy working on my 1410 in FPGA project, and there is now more to share, though I have not done much actual work since February - been too busy playing with other "toys". 8D First, I finished working through all of the IBM 1410 and IBM 1415 Automated Logic Diagrams - generating VHDL and testing the results with test benches. [Note that this includes the built-in 1401 compatibility mode, activated at the flip of a switch.] That took most of 2020. So, the CPU generation in VHDL is now more or less complete, and I added a hand coded memory module for memory, as core is kind of hard to find on an FPGA development board. ;) I am currently using a Digilent Nexys 4, but I think it might have even fit on a Nexys 2 - there is plenty of room to spare, and there isn't anything in the VHDL aside from, maybe, the memory implementation (though even that is pretty generic VHDL). With this the CPU runs, at the very least, Unconditional branch (Jump), Halt, NOP and Set Word Mark instructions seemingly correctly - I haven't tried any others. Somewhat surprisingly, aside from issues with the hand coded VHDL in triggers and the need to communicate pins tied to logic one or zero, the auto-generated VHDL works untouched. I have updated the github repository for the C# database application that generates the VHDL from time to time (and which includes the complete database) at http://github.com/cube1us/IBM1410SMS There is now a *new* repository, http://github.com/cube1us/IBM1410FPGA which holds the generated VHDL, some hand coded VHDL modules for certain SMS cards (typically for triggers, for example), the console and test benches I used along the way, and VHDL "Integration Tests" which are designed to be loaded onto the board - the current one being IntegrationTest3. There will be, eventually, a third repository which will contain the C# code that "hosts" the IBM 1410 console and peripherals, communicating with the FPGA over a high speed serial over USB connection. I figured out that this should allow me to emulate peripherals without having to resort to sending data over Ethernet, SPI, I2C or the like. I have just started that, so it really isn't at a point that there is much to share. Once I have a console working (which will require a re-do of the console VHDL implementation, which right now communicates in ASCII, but should probably be using BCD), I should be able to pre-load into memory some of the CPU diagnostics, by loading a diagnostic routine into either my 1410 simulator (http://github.com/cube1us/1410), or Richard Cornwell's emulator in SimH and then taking a snapshot of "core" to pre-load into the FPGA. At that point I expect I will be able to test the CPU pretty thoroughly. I hope and expect that will happen this year sometime. Unfortunately, I do not have the ALDs (Automated Logic Diagrams) for the IBM 1414 I/O Synchronizers, but I do have the Instruction Logic Diagrams which should allow me to code VHDL to emulate card, tape and maybe eventually even disk functions, so those might take a while. If anyone cares.... ;) JRJ

2 years, 12 months

Looking for the person I sold an eMachines eOne to at the VCF Swap Meet on April 24

by tony.aiuto＠gmail.com

*I found more related goodies you can have for the shipping. You can reply direct to me or on this thread.*

2 years, 12 months

DEC PDP-11/45 backplane +5 ECO

by fritzm＠fritzm.org

Hi Josh, Among the pictures linked from your message about the H742a parts, there is one picture of you backplane. I have been looking for some time for information about the following 11/45 ECO: > KB11-00001 CODE: D May-72 [ECO] > > Problem: Etch carrying +5V current from Mate-n-Lock pins to backpanel pins is not heavy enough to carry required current. Correction: Run 24AWG wire in parallel with etch on panels which already have Mat-n-Lock assembly installed. Increase thickness of conductor with solder bead if Mate-n-Lock assembly not installed. PDP-11/45 system serial number 101 and later. The wiring arrangements at the top of your backplane look to be a bit different from mine, and I believe you may have this ECO implemented. While you have your backplane out, could I ask that you take some closeups around the Mate-n-Locks along the top? I'd be very interested to see the board traces and the details of the red bus wiring there. Pictures of the toasted 11/45 suggest that the original machine had the older power wiring scheme (distribution panel mounted vertically on back of cabinet instead of horizontally at top of cabinet, etc.) although your KB11A serial number badge is >2000, which is curious...

3 years

DEC RF08/RS08 module placement info

by michael.99.thompson＠gmail.com

I sent Josh pictures of the complete RF08/RS08 that John Wilson donated to the RICM. I will send detailed pictures of the RS08<->RF08 cables next week. -- Michael Thompson

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test-drb May 2021