Image Map Image Map

Search:

Type: Posts; User: intabits

Page 1 of 2 1 2

Search: Search took 0.01 seconds.

  1. Replies
    18
    Views
    1,170

    The switch register can only be tested in the...

    The switch register can only be tested in the system, as the transceivers that also enable it onto the MCU input bus are open collector, and need the Unibus pullups.
    Not quite true, it can be done...
  2. Replies
    3
    Views
    601

    I was thinking of uploading these to some other...

    I was thinking of uploading these to some other ROM repository (name escapes me ATM), but that was primarily for test equipment anyway. I hadn't thought of Bitsavers for ROMs, but I'll get around to...
  3. Replies
    18
    Views
    1,170

    Dave and Mattis, Thanks for your help and...

    Dave and Mattis,

    Thanks for your help and interest.

    The little Cypress FX2 module, with my input protection PCB, and the Pulseview software is the sum total of my experience with logic...
  4. Replies
    18
    Views
    1,170

    Hi Dave, Thanks for the kind words. As I...

    Hi Dave,

    Thanks for the kind words.

    As I didn't know how far I'd have to take this, and how general purpose it might turn out to be, the PC software is fairly elaborate - more than it needs to...
  5. Replies
    18
    Views
    1,170

    Yes, that was the first thing I tried, as the...

    Yes, that was the first thing I tried, as the MCUs are the only interchangeable part.
    Both of them worked in the good M7859. (I think I mentioned that in the previous video?)
    But in case of...
  6. Replies
    18
    Views
    1,170

    PDP-11/04 Console Repair - Part 1 and 2 of ?...

    This is becoming quite a saga!

    In this video, I find and fix a fault in the M7859 board (a 74175 Quad D flip-flop), plus uncover and fix a bug in my testing hardware.

    But after that, the board...
  7. Replies
    18
    Views
    1,170

    Done with a very old version of "RFFlow". I...

    Done with a very old version of "RFFlow".
    I don't like it very much, because it has many shortcomings in my opinion.
    But one thing I do like about it is that diagrams can be embedded in a word...
  8. Replies
    18
    Views
    1,170

    Thanks for comments above. I'm working on the...

    Thanks for comments above.
    I'm working on the next stage and part 2 video atm.
    I believe I've found the cause of the (hopefully only) problem, which is that the Address Register Clear FF [E6-6] is...
  9. Replies
    18
    Views
    1,170

    PDP-11/04 Console Repair - Part 1

    Continuing with my PDP11/04 and 11/34 repairs, now that the power supplies are sorted,
    next comes the console and its interface, the M7859 board (together termed KY11-LB)
    These work properly on...
  10. Replies
    3
    Views
    601

    Hi Mattis, I have both the early version of...

    Hi Mattis,

    I have both the early version of M7859 (described by MP00015_KY11-LB.pdf),
    and the later version with E75,E76 added, and E14,20,31,37 changed (described by MP00015_KY11-LB_Jan78.pdf)
    ...
  11. Replies
    28
    Views
    1,691

    Looking at your other thread, I'm still not clear...

    Looking at your other thread, I'm still not clear on what you have there.

    Does this unit have any DEC boards in it? What are they?
    Does it have a front console, with the octal keypad, etc? (The...
  12. For this particular cable, I can't see this as...

    For this particular cable, I can't see this as anything but an error.

    The placement of the J1 connectors on these two PCBs requires that the cable have a right angle fold at a minimum - fine. If...
  13. (Unable to edit the original post) I've made...

    (Unable to edit the original post)

    I've made some corrections, changes, and additions to the diagram:-
    https://i.imgur.com/dA5aGNg.png

    HiRes:-
    https://imgur.com/aGfOSIl
  14. KY11-LB (pdp11/04/34) "Documentation error" & block diagram

    After cleaning up and sorting out the PDP11/04/34 power supplies, I'm starting to fire up my two machines with boards inserted - first off, just the M7859 console interface and the M9302 terminator...
  15. Replies
    6
    Views
    446

    Thanks for the offer - PM sent! I agree that a...

    Thanks for the offer - PM sent!

    I agree that a superglue bond would probably be far too brittle to withstand repeated flexing.

    I've resolved to first try just a more robust version of my...
  16. Following on from the checkout, fix, modify and...

    Following on from the checkout, fix, modify and test of the H777 power supply from my PDP11/04, the exercise is repeated for the PDP11/34 PSU.

    For my future reference and hopefully that of others,...
  17. Replies
    6
    Views
    446

    Thanks for the reply. I think I understand what...

    Thanks for the reply. I think I understand what you mean there, though it does seem rather involved (and somewhat fiddly).

    The solution I've come up with for the moment with the duct tape is...
  18. Replies
    6
    Views
    446

    Broken button on DEC PDP-11/04 KeyPad

    So this ham-fisted clown was cleaning the front panel keypad of my 11/04, and not knowing how fragile they were, broke one of the buttons off.

    The buttons are part of the frame, all being a...
  19. Replies
    8
    Views
    402

    Thanks. I had wild oscillation with light bulbs,...

    Thanks. I had wild oscillation with light bulbs, due to their high PTC, which is the main reason why I made this.


    As I mentioned, there are many options to extend operating time. I guess it...
  20. Replies
    8
    Views
    402

    Oil filled dummy load for H777 PSU

    This is a cheap and cheerful method to make a dummy load that will happily dissipate 150 Watts for 15 minutes, which is long enough for most types of testing.
    It consists simply of PVC piping with...
  21. Yes, it is. Although the 6v rating is 20% above...

    Yes, it is.
    Although the 6v rating is 20% above the 5v operating voltage, it is *only* 1 volt. Maybe transients (and possibly negative ones) from the inductor and the switching action, (or short...
  22. I've just done a teardown, clean, checkout,...

    I've just done a teardown, clean, checkout, repair, modify and test of the H777 power supply from the PDP-11/04.

    The H777 PSU

    https://i.imgur.com/7Pa6TTT.jpg


    The main +5v @25A regulator...
  23. Thanks. Done.

    Thanks. Done.
  24. Thanks for the kind words and advice. I do...

    Thanks for the kind words and advice.

    I do have 2 RX01's, and some discs. I think they came with the 11/34 (or 11/05). The 11/04 came with nothing else.

    Not sure how I missed the DEC subforum....
  25. Just added many hi-res photos of the boards in...

    Just added many hi-res photos of the boards in these machines to the gallery at:-
    https://imgur.com/gallery/1czglgJ
Results 1 to 25 of 33
Page 1 of 2 1 2