July 2025 - cctalk - classiccmp.org

by Mark Kahrs

LSSM is looking for a copy of the RK06/07 Technical Description Manual, EK-RK067-TD-001. If anyone can give or loan it to us, we can scan it as well for public distribution. Thanks.

1 week

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Selling a Wang calculator

by pontus

Hi I know this isn't exactly the right group for this. But I have a fairly uncommon Wang calculator for sale and am not sure where to post about it. I've tried "Vintage Calculators Buy & Sell" on facebook without much luck. I see there is some calculator activity on discord, so I'll post about it there but I'd be happy for suggestion of other venues before I go the E-bay route. Below is the blurb I posted on facebook and here is a link to photos of the thing: https://drive.google.com/drive/folders/1gNdVSsNDxDL1Ukjh13-2ElJXRiWKQ5rx?us… FOR SALE: a Wang 362E electronic calculator in good condition, some scuff marks and light scratches but the inside is clean and looks to be complete. It comes with the 370K programming keyboard with nixie tube display in original dust cover, two card readers model 371 (with feet), four manuals in English and one in Swedish with handwritten notes. Also included is an IBM port-a-punch in box. I have decided not to test it in order to avoid causing any damage from improper handling or due to problems with ageing hardware. Located in Uppsala, Sweden. I will ship internationally but please allow some time for me to package it properly and figure out the best shipping options. I have shipped heavy computers and even CRTs with success, so I’m not without experience. Give me an offer :)

1 week

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9-Track Tape Extraction

by lukeparkerson1＠gmail.com

Hi all, I recently got my hands on what I believe is a 9-track tape, dated 1986, which has some old survey data stored on it from a university research project several decades ago. I'm hoping to be able to extract the information from the tape and convert it to a more modern data file accessible to the public, but I don't know very much about these tapes nor do I have 9-track tape equipment. I'm wondering if anyone who is more familiar with this technology can tell me it's even still possible to extract this data, and if so, is there's anyone here who can try and run the tape, or knows someone with a working 9-track tape drive? The frame is not in the best shape, but the tape is hopefully fine. Here's a photo: https://drive.google.com/file/d/1PrdBnIWUO4-317ZSwqvY-TD6dHr2CxC8/view?usp=… Thanks, Luke

1 week

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Ferroresonant transformer mystery

by Tom Hunter

Recently I got a nice and complete PDP-8/s from the US. The power supply uses a ferroresonant transformer which in addition to the standard primary and secondary windings has a separate 2.3H winding connected in series to a 2uF 660VAC capacitor forming a resonant "tank" circuit. The transformer's secondary side and the resonant circuit are operated in saturation. There is a magnetic shunt to prevent the primary side going into saturation as well. It accepts a wide input voltage range, but is very sensitive to the input frequency of 60Hz. This is quite a nice if not elegant design for the period in question, but maybe not the most efficient. As I live in Australia I get 240VAC and 50Hz as opposed to the US 115VAC and 60Hz. I can easily convert our 240VAC to 115VAC with a step-down transformer, but cannot easily supply 115VAC at 60Hz. So I was considering using a step-down transformer to get the 115VAC, but modify the resonant "tank circuit" for 50Hz. Unfortunately there is some magic I don't understand. The resonant frequency of a LC circuit with L=2.3H and C=2uF is about 75Hz not the expected 60Hz. Otherwise I could just solve the standard LC resonant circuit formula for C and plug in 50Hz and 2.3H to get the required C. Obviously ferroresonant transformers are more complex than this former software engineer can grasp. Could any experienced EE with relevant transformer knowledge please chime in and help me understand how to redimension the tank circuit to use 50Hz instead of the original 60Hz input. Obviously I could replace the entire power supply with two modern switch mode supplies to create the two rails, but it would be really nice to keep the original supply and just reversibly adapt it for 50Hz. Thanks and best regards Tom

1 week

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Re: Lee Felsenstein at VCF West August 1 at 4:30PM

by John Foust

At 04:22 PM 7/10/2025, you wrote: >Lee Felsenstein at VCF West Friday, August 1 at 4:30PM. >He will talk about the 50th Anniversary of The Homebrew Computer Club. Here's the line-up: https://vcfed.org/events/vintage-computer-festival-west/vcf-west-speakers/v… Not just Lee... but also Bob Marsh of Processor Tech, and Harry Garland of Cromenco, and Dan Sokol of Apple... And then for the Amiga 40th events, Dale, RJ, Trevor, Perry, Willie, Marco, Bill, Aaron, Brad, and me, too! And Sellam is there! - John

1 week

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Comstar System 4 Intel 4004 based Industrial Computer Documentation

by Christian Liendo

I was able to obtain a number of documents that pertain to the Comstar System 4. I spoke about this computer in the past but I have scanned some documentation that should help explain this unique computer People who have been interested in the Intel 4004 might find this interesting The Comstar System 4 Reference Manual is rather detailed on the computer itself and it's applications This is the Complete Comstar System 4 Reference Manual https://archive.org/details/comstar-system-4-reference-manual_202507 Warner & Swasey Reference Manual https://archive.org/details/warner-swasey-comstar-star-system-reference Comstar System 4 Programming Manual https://archive.org/details/comstar-system-4-programming-manual Comstar System 4 Tester Manual https://archive.org/details/wscomstar-system-4-test-manual Comstar System 4 CPU Module Schematic https://archive.org/details/comstar-system-4-cpumodule Comstar System 4 Serial Communications Schematic https://archive.org/details/comstar-system-4-serial-communications Comstar Star System 4 RAM Module Schematic https://archive.org/details/comstar-star-system-4-rammodversion Comstar Star System 4 HTL I/O DATA Module Schematic https://archive.org/details/comstar-star-system-4-iodatamodule Comstar Star System 4 PROM Module Schematic https://archive.org/details/comstar-star-system-4-prommodule Comstar Star System 4 PROM 1k 2k Module Schematic https://archive.org/details/comstar-star-system-4-prom-1k-2k-module Warner & Swasey Comstar System 4 Process Control Language https://archive.org/details/wscomstar-system-4-pclref-manual Warner & Swasey Computer Division Comstar System 4 Machine Language / Assembly Language Reference Manual https://archive.org/details/wscomstar-system-4-assembly-language Comstar System 4 Program Analyzer Reference Manual https://archive.org/details/comstar-system-4-reference-manual Computer History Museum's Archive of the Manual https://www.computerhistory.org/collections/catalog/102686568 Comstar Computer Systems Process Control Language Data Sheet https://archive.org/details/comstar-star-pclcompiler-data-sheet

1 week, 3 days

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Video: Introduction to Chiptunes by Inversephase @ VCF East2025

by Jeffrey Brace

Introduction to Chiptunes by @inversephase video released today (7/14/2025): https://youtu.be/i0v712l2RWE Enjoy! Jeff Brace

1 week, 3 days

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Interact One Message Center

by Steve Lewis

Hey all, I'm trying to track down a manual or instructions for the Message Center program on the Interact One (from 1978). I've run this in the MAME emulator, and it seems the program has a "partial" BASIC-like interpreter. You can do line numbers, like 10 HELLO 20 WORLD Then issue the command SCROLL, and it will start scrolling text in the numeric sequence they were specified. Then you can also do commands like FLASH, BUZZ, BEEP in its equivalent of "immediate mode" -but I don't know yet how to specify these commands in the numeric program. And in the emulator, I can't yet parse the commands PLOT, SOUND, SIZE - these "message center" program specific commands,not BASIC (BASIC on this system is loaded from tape). Anyway, a manual on a program for the Interact One called "Message Center" is what I'm trying to track down. Thanks, Steve

1 week, 6 days

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IBM System/23 Datamaster 5324 Towers and IBM 5247 HDD Tower Available

by Ali

Hello All, A long time ago I acquired a System/23 desktop unit and eventually a number of the tower units including the HDD tower unit. The plan was to setup a System/23 Muli-User system with multiple terminals connected together. Well, like many great plans real life got in the way and the units have been sitting in storage for a few years. I have accepted that this is one of the projects I will never get to and it is time to pass them on to someone else who can enjoy them. The systems are in SoCal (Upland, CA to be more exact). More info can be found at the following links: https://forum.vcfed.org/index.php?threads/ibm-system-23-datamaster-5324-towe r-model-of-the-5322-with-original-clicky-keyboard.1253651/ https://forum.vcfed.org/index.php?threads/ibm-system-23-datamaster-5324-towe r-model-of-the-5322-with-one-floppy-drive.1253652/ https://forum.vcfed.org/index.php?threads/ibm-system-23-datamaster-5322-or-5 324-hdd-tower-model-5247.1253653/ I hate to part/scrap them as the towers rarely show up so I am hoping someone local would be interested in them. Feel free to email me directly or reach out through VCF. Thanks -Ali

1 week, 6 days

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Vax boxes, parts

by Paul Anderson

I did some digging and found one 3000-400 with no lid( It could be here somewhere) and I'll have to move it to look it over to see what's there. I had 6 or so 3000s and I guess I sold them, but more digging to do. MV3100 M76 MV3100s I can't get to the model number 4000-60 5000-25 5000-125 5000-133 5000-200 I had to pull some boards and made a small list. M7621 M7622 M7624 M7625 M7626 54-21149 KN15 If you need a board I have not listed, please email me off list. If I haven't replied, bug me. I did not list qtys- some items are more than one. Thanks, Paul

2 weeks

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