• Please review our updated Terms and Rules here

Search results

  1. G

    RK05 disk emulator development and discussion

    For continued discussion of RK05 disk emulator topics. Creating a new thread in case members prefer to comment here. I have no expectations except to have an opportunity share what I've worked on and to learn from those who share their comments, questions, anything. There's another thread with...
  2. G

    Restoring a PDP-8/L

    First step was to remove the power supply, disconnect and/or remove the 3 large electrolytic capacitors and reform them. The reforming jig is very similar to the one used for reforming electrolytics in the PDP-8/M. PDP-8/M supply reforming with schematic...
  3. G

    Flip-Chip Module Tester, bring-up and experimentation

    Recently put together an M-Series Flip-Chip Tester, the original design by Warren Stearns. This is based on the variation by MThompson and PCB by Vince that was modified to connect to an FTDI C232HM interface. In this variation, the MISO and MOSI signals of all 5 GPIO expander chips are tied to...
  4. G

    replacement for DEC AC input Y-capacitors, aka common-mode capacitors, aka bathtub capacitors

    Does anyone remember this post? There was a post somewhere on the forum about replacement parts for the AC input common mode filter capacitors, or Y-capacitors, or "bathtub" capacitors, in an older DEC machine. I think it was by someone who posts often, and they recommended that the filter...
  5. G

    Mini-Omnibus backplane for debug and minimal system

    6 months ago I built a small Omnibus backplane. For a long time I didn’t have a PDP-8/E/F/M chassis with backplane and power supply and wanted to get a system running using my Omnibus board collection. I’ve had a number of requests to release the design files of this mini backplane to use it...
  6. G

    H740 Power Supply, what's your Q1?

    The simplest circuit in the H740 supply (PDP-8/M), the +15V output, is giving me trouble. I'm seeing ~20Hz oscillations when the +15V output is loaded above 0.5A. Q1 in both of my supplies is a 2N3791, a PNP power transistor (not a Darlington). However, the schematic identifies Q1 as part number...
  7. G

    Fun stuff, just got a new old PDP-8/M chassis

    I’m excited to now have a PDP-8/M chassis for my system which was previously open-frame with a home-brew backplane and powered by lab supplies. I thought it might be interesting to share my experiences and benefit from the knowledge of experts in this group. PDP-8/M chassis, freshly unboxed...
  8. G

    DEC PDP-8/e, PDP-8/f or PDP-8/m chassis with front panel and backplane

    Looking for a PDP-8/e, PDP-8/f or PDP-8/m chassis with front panel, backplane, and power supply, preferably in working condition. I already have most of the M8xxx boards needed to build up a working system.
Back
Top