• Please review our updated Terms and Rules here

Recent content by Qbus

  1. Q

    IBM 5100 - worklog

    Pin to pin on AC input side 0.3 Ohms! man that thing is toast. Yes, you can just jump around it. that was intended to prevent the HF Radio noise of the power supply from getting back out on the AC Line along with preventing other noise on the house side of the line getting into the power supply...
  2. Q

    IBM 5100 - worklog

    If you have the system plugged into a GFI protected circuit it may trip due to leakage of the AC Input filter. The threshold of the GFI circuits is way sensitive and will trip on the smallest amount of AC leakage to ground. A lot of those old AC Line filters were way too leaky when new but back...
  3. Q

    IBM 5100 - worklog

    Been over twenty years ago but recall having to replace one of the high voltage DC filter capacitors in the power supply. They have a first-generation switching supply and the filter capacitors in the primary side tended to short. Easy to check by opening up the power supply and checking the...
  4. Q

    Westinghouse Flight Computer

    Couple pictures, think this was used in development of the AN/AGP-66 Radar and although pure speculation think it may have intrepid IFF data and worked with a character generator to display that data on the radar screen. That along with cursor display and the like. Have seen Data General Nova...
  5. Q

    Westinghouse Flight Computer

    Yes! I now think the mysterious AM934151G 24 pin things are the Fairchild 9341 ALU, the original Fairchild device that’s equal to a 74181. Will need to do some checks to confirm like seeing if carry moves to the next stage and things like that but that’s what I am thinking right now. Found a...
  6. Q

    Westinghouse Flight Computer

    Always had fun with this stuff, it’s like being in a room in the dark with a blindfold. So far I know a couple things. First is that it’s an eight bit data bus with memory built out to 8K, the CU cards have seven Harris 0512 64 X 8 PROMS with all seven sharing the same address bus but the...
  7. Q

    Westinghouse Flight Computer

    Picked up a couple Westinghouse prototype computers that were part of the first-generation systems used on the F-16, No microprocessor chip, all discreet components. They have around eight cards in them. Two memory cards that are 4K by 8, a termination card, what appears to be a serial card, a...
  8. Q

    PDP11/83 in London storage

    C1 and C2 are the two biggest capacitors on the power supply card. Also you can remove them just by unscrewing the two screws that attach them to the card. Disconnect everything from the back panel and from what i remember undo the two screws on the corners and the entire mess, power supply...
  9. Q

    PDP11/83 in London storage

    If you want to go the whole reforming rout its not that big a deal to pop out the two big electrolytic C1 and C2 and just use a bench supply to run them up gradually outside the power supply and then when satisfied with there state and after discharge reinstall them in the power supply. Be...
  10. Q

    Came Across A Store On eBay that has some unusual GRiD items

    Don’t know what to say, no experience with this guy so just don’t know. Will say that you have to be careful stacking grids up like that. Back years ago, purchased a stack of maybe a dozen 1550 laptops and all but two had the displays broken thru being loaded and unloaded and stacked up. Try to...
  11. Q

    Came Across A Store On eBay that has some unusual GRiD items

    Been away for some time, sorry. Hope I am not wearing out my welcome but looking at that guys store just gives me the impression that hes a Hack, someone who is into it for the money. But maybe I am wrong. Think almost all that Grid stuff I have and know the history and condition of and would...
  12. Q

    Possible Philco Transac 2000 board

    That IBM SMS card database is ineradicable! thanks for turning us on to it. Will waste hundreds of hours here at work looking at that.
  13. Q

    TRS-80 model 2

    Went thru all the Radio Shack stuff over the weekend, wanted to get it out of the cardboard boxes and clean off all the covers. Was going to catalog all the software but there is too much to list, twenty-two volumes in all. One of the accounting binders still had a price tag on it from 1980 for...
  14. Q

    Mid Atlantic Radio Shack TRS-80 II System, printer and software

    Went thru all the Radio Shack stuff over the weekend, wanted to get it out of the cardboard boxes and clean off all the covers. Was going to catalog all the software but there is too much to list, twenty-two volumes in all including two owners manuals, one Technical manual, things like the hard...
  15. Q

    Mid Atlantic Radio Shack TRS-80 II System, printer and software

    Ok, will do some pictures this weekend. Not done an inventory of what manuals and software are with it yet so this will be an opportunity!
Back
Top