Author : malcolm

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The 871B Power Controller is a single-phase 240VAC power controller found in some PDP-11 systems. It has 6 switched power sockets. One of my holiday projects was to replace the faulty neon indicator in this Power Controller. I have just posted a short webpage with some information about this repair, and some reference information about ..

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It’s time to thin out my vintage computer collection a little. Below is a list of items currently available. My order of priority for finding new homes for this equipment is as follows: Free of charge (or a swap, if offered) to people in the following categories: Under 21 years of age; or Retired or ..

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Last weekend I started to investigate a “decdatasystem” in my collection. I thought I only had the TU10W tape drive and RK07 hard drive. I was very surprised to find that below the TU10W is an entire PDP-11/34 chassis with the controllers for both drives. More information available here -> PDP-11/34 dec..

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I’ve just put up a webpage with some reference information about various RS232 connectors, including the DEC423 MMJ connectors. If interested, please take a look here -> http://avitech.com.au/?pa..

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Introduction In May 2015 I went to VCF Southeast 3.0 in Roswell GA. This page has links to my two presentations and supporting materials. Where links are already provided in the presentations themselves, I’ve not included further copies of them below. Comments and other feedback are very welcome. Floppy Disk Imaging Powerpoint Presentation Z80 Assembly ..

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I have some original VMS CDROMs. I was looking for a way to image these (for use with SIMH) and also a way to write ISO images back to blank CDs, to use on real hardware. This should be a fairly simple process using a modern Linux computer and the “dd” command, except for one ..

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A recently acquired part of my collection includes what I think is an IBM processor presumably from a large system. The mounting frame is in a 3 x 3 grid. 6 modules are fitted and the other 3 locations are empty. This thing is huge – about 30 inches square. And the weight is around ..

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This post takes a brief look at the current loop connectors used by DEC. The main focus of this post is the cabling needed to connect a VT220 terminal to a computer (such as a PDP-11/10) using the 20mA current loop interface. DEC’s standard connector DEC used an 8-pin Mate-N-Lok connector for all current-loop cabling ..

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I’ve got a couple of projects on the go that use the PIC18F2550 (or PIC18F2553) microcontrollers. Normally I program PICs in-circuit with a PICkit 3 programmer while debugging my code. While this works great, I also need a way for people to easily field-upgrade my PIC firmware, without the need for a PIC programmer. So ..

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