Published 13 Jun 2021

DEC H-500 Computer Lab

\\ ===== Overview ===== To help train electrical engineers in digital electronics Digital Equipment Corporation (DEC) produced a digital logic trainer together with a training course. It allows students to connect up various configurations of basic logic gates following a workbook to get a hands on idea of what it was all about.

DEC H-500 Digital Logic Trainer

There is a 110V version (H-500) and a 240V version (H-500-A), but all the logic runs on 5V. It came with a Computer Lab workbook (item B-350) and an assortment of 107 patch cords of assorted lengths from 2.75" to 24.75" (item "916"). There was also a Computer Lab Teaching Wall Poster (24" x 36"). {{ :electronic:equipment:h500:dec-clw-3.gif?300|H-500 Computer Lab Poster}} ===== Hardware description ===== The logic gates are provided by 12 TTL logic chips: 7473, 7400, 7420, 7450, 7400, 7473, 7473, 7410, 7420, 7450, 7410, 7473. The chips are mounted on the under side of a PCB (item H500 PATCHCORD PANEL5004577 5404576B). There is a separate PCB containing the input switches, output lights, oscillator, and power supply (**BEWARE** mains voltages are present on this board). There are 8 rocker switches for providing logic 0 or 1 inputs, and 3 momentary rocker switches to provide pulsed inputs. Additionally there is also a variable resistor control for an oscillator that has 6 selectable clock ranges, 3 "fine" and 3 "coarse" \\ \\ \\ \\ The patch cords are colour coded according to length: {{ :electronic:equipment:h500:p6148949a.jpg}} ^Colour^Length^Quantity| ^Brown|2.75"|20| ^Red|4.75"|30| ^Orange|6.75"|25| ^Yellow|8.75"|20| ^Green|16.75"|10| ^Blue|24.75"|2| And they have uncommon tapered pins crimped onto each end: {{:electronic:equipment:h500:p6148952a.jpg?200}}{{:electronic:equipment:h500:p6148953a.jpg?100}}{{:electronic:equipment:h500:p6148956a.jpg?100}} \\ \\ I've got two versions, one with light bulbs as output, the other with red LEDs. I'm not entirely sure whether the LEDs were a standard version, or whether someone has retrofitted them (possibly to replace failing light bulbs). ---- *DEC H-500 schematic: {{electronic:equipment:h500:h500_schematic.png|DEC H-500 schematic}} ---- ===== Examples ===== ^Example 1^ {{:electronic:equipment:h500:p6148894a.jpg?200|DEC H-500 label}} {{:electronic:equipment:h500:dsc_2578a.jpg?200|DEC H-500 label}} {{:electronic:equipment:h500:dsc_2570b.jpg?400|DEC H-500 top view - LEDs}} {{:electronic:equipment:h500:dsc_2573b.jpg?400|DEC H-500 bottom view}} {{:electronic:equipment:h500:dsc_2575a.jpg?200|DEC H-500 label}} {{:electronic:equipment:h500:dsc_2576a.jpg?200|DEC H-500 label}} {{:electronic:equipment:h500:dsc_2579a.jpg?800|DEC H-500 disassembled view}} {{:electronic:equipment:h500:dsc_2580b.jpg?400|DEC H-500 inside view}} {{:electronic:equipment:h500:p6148885a.jpg?400|DEC H-500 mounting batten}} {{:electronic:equipment:h500:p6148883a.jpg?400|DEC H-500 mounting batten}} {{:electronic:equipment:h500:p6148886a.jpg?400|DEC H-500 led}} ---- ^Example 2^ {{:electronic:equipment:h500:p6148896a.jpg?200|DEC H-500 label}} {{:electronic:equipment:h500:dsc_2584b.jpg?400|DEC H-500 top view - incandescent}} {{:electronic:equipment:h500:p6148898b.jpg?400|DEC H-500 inside view}} {{:electronic:equipment:h500:p6148928a.jpg?400|DEC H-500 light}} \\ \\ ====== References and Additional Resources ====== * {{electronic:equipment:h500:computer_lab_workbook.pdf|H-500 Computer Lab Workbook}} * {{electronic:equipment:h500:digital_computer_lab_workbook_1969.pdf|H-500 Computer Lab Workbook}} copy 2 * {{electronic:equipment:h500:computerlabteachersguide.pdf|H500 Computer Lab Teachers Guide}} * [[https://archive.org/details/bitsavers_dechandboobWorkbook1969_6837997|Some Thoughts from the Author of workbook, John Hughes]] * [[https://www.instructables.com/DEC-H-500-Computer-Lab-Reproduction/|DEC H-500 Computer Lab Reproduction]] * [[https://hackaday.io/project/170232-dec-h-500-computer-lab-reproduction/log/185600-the-designer-of-the-original-h-500-computer-lab-reaches-out|Notes from John Hughes about Computer Lab]] * [[https://hackaday.io/project/170232-dec-h-500-computer-lab-reproduction/log/185604-more-from-john-hughes|More notes from John Hughes]] * [[https://so-much-stuff.com/pdp8/computerlab/computerlab.php|Vince Slyngstad's DEC "Computer Lab" page]] * [[http://www.decodesystems.com/dec-clw.html|DEC Computer Lab]]

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