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  1. M

    W904 hex extender board for UNIBUS

    Just wondering if anyone here has a W904 hex extender board? If so, it would be great to see some high-res pictures of it. I'd like to make a couple of them, and I'm keen to see some basic details (number of layers, whether there is an earth trace between signal lines, which pins are...
  2. M

    Cromemco System Three restoration - initial questions

    I'm at the early stages of attempting to restore a Cromemco System Three. This thing is built like a tank. It's the second-heaviest S100 machine that I own. This one is fitted with a ZPU / 64KZ / TU-ART / 16FDC (fitted with RDOS 2.01 PROM) and a single PerSci 299 drive. It came to me with...
  3. M

    Wanted: PDP-11/34 Backplane

    A friend here in Melbourne is attempting to build up an 11/34 from scratch. He already has most of the boards needed (though could do with some spares) and has a front panel. The key part missing is a backplane. Does anyone have a backplane, or perhaps a half-height chassis, that they can...
  4. M

    WTB: Memorex 651 Floppy Drive (for software restoration project)

    I'm searching for a Memorex 651 drive to use for a (non-commercial) data recovery project. The 651 is an 8" drive, but predates conventional 8" drives and is physically very different (hard sectored, different RPM, etc). If you have one that you are prepared to sell, please let me know. Here...
  5. M

    QBUS Card Reader Controllers

    I am aware of the CR11 (M8290/M8291) controllers for the UNIBUS. What card reader controllers were available for QBUS? The only one I am aware of is the MDB MLSI-CR11. I have one of those boards and have just scanned the manual for it -> http://avitech.com.au/?p=3749 I'm keen to find out...
  6. M

    Parallel printer cable for PDP-11

    I have a couple of cables with identical wiring that appear to be for a parallel printer. They have a 40-pin Berg connector on one end and a Centronics-style d-shell connector on the other end. The Centronics end is wired for the usual signals (D0-D7, STB, Busy, Fault). The wiring at the Berg...
  7. M

    PDP-8/e earth leakage problem

    I recently moved house and found that my PDP-8/e triggered the RCD (Residual Current Device) in the switchboard of my “new” (15 year old) home. The problem was quickly identified to be the Sprague 0.1uF “line-to-earth” capacitors in the 8/e’s H724 Power Supply. In summary: the line-to-earth...
  8. M

    Unusual RL disk packs

    Just wondering if anyone can help me identify an RL disk cartridge please. The cartridges are marked "Control Data 848-12". When I try to LOAD these on a known good RL01 system (QBUS with RLV12 controller), the drive just makes a clicking sound about once per second. The READY light never...
  9. M

    Recently scanned RQDX Field Service Tech Tips

    Going through some boxes of documentation, I found some rather obscure DEC "Field Service Tech Tips" (and DEC uNote #043) that relate to the RQDX controllers. uNote #043 is already online elsewhere, but I had not seen these Tech Tips before. The 4 documents that I have scanned are: DEC...
  10. M

    Problem installing "FTP and Telnet Package for Small Systems" for RT-11

    I'm attempting to install the Alan Baldwin (Kent State University) FTP and Telnet Package for Small Systems for RT-11 from the supplied TCPIPM.DSK logical disk. My target operating system is RT-11 V5.3 SJ. The requirements are stated to be "an RT-11 system with 56K bytes of memory and a...
  11. M

    Problem reading binary data from CR11 card reader

    I've been messing around with reading punched cards from a CR11 under SIMH on a PDP-11/04 running RT-11 V5.3. With the help of the card-file translation tools written by Doug Jones, I'm able to read-in a short BASIC program (consisting of 4 cards) after configuring the CR driver (in RT-11) with...
  12. M

    Arduino-based front panel for QBUS backplanes

    Just thought I'd post a link here to a new Arduino-based project. The Arduino monitors some front panel switches (Power On/Off, Run/Halt, LTC On/Off, Restart) and provides the necessary output signals for the 10-pin connector on the rear of a QBUS backplane (BDCOK H, BPOK H, BEVNT L, BHALT L)...
  13. M

    Konan "Blue Sky" MFM Controller - Looking for documentation

    I have a Konan MFM controller that I am trying to find documentation for. This was part of a large SD Systems 600 all-in-one S-100 system. The controller consists of a daughter-board that plugs into the Z-80 socket on the S-100 CPU board, and an external double-sided blue PCB that includes a...
  14. M

    Pertec T8640A Tape Transport

    Just wondering if anyone here can help with some high-level information about hooking up Pertec T8640A Tape Transports to a QBUS (or UNIBUS) PDP-11. I have searched these Forums without much success. I have 3 x T8640A Tape Transports. Each one has 3 x 36-pin edge connectors on them. One T8640A...
  15. M

    VAX XMI Boards - free to good home

    I have 6 of these boards: I'm not sure what these are, but it has been suggested they are XMI memory boards. They have surface mount chips on both sides of the boards. I really don't want to send these to recycling. Is there anyone who will take them for the cost of postage plus US$15 to...
  16. M

    DEC items for sale, swap or giveaway

    I have a collection of DEC items available for sale, swap or giveaway. They are mostly VAX or MicroVAX items, as well as a few PDP-11 items. These are in Melbourne, Australia. I appreciate this may not be of much interest to the rest of the world. If interested, please take a look here ->...
  17. M

    pdp-11/34 decdatasystem

    Found this pdp-11/34 decdatasystem buried in the back of a recently acquired collection. I initially thought I only had the TU10W and RK07 drives. But once I figured out how to open the lower front panel (thanks Luigi) I discovered there was an entire 11/34 chassis down there - complete...
  18. M

    DEC H3171-A RS232 Distribution Panel

    I'm looking for a neat way to put a row of 4 x DB25M connectors inside the back of a corporate cabinet that houses my 11/23 system. I found a H3171-A RS232 Distribution Panel that looks to be perfect for this (see pictures). But the cabling has me stumped. On the back of the H3171 is a...
  19. M

    Imaging DEC VMS CDs - Block size considerations

    I've just been messing around with imaging some original DEC VAX/VMS CDs (original distributions of the operating system). I was expecting that making ISO files of the original CDs, and then burning those ISOs back to blank CD-R disks on a PC would require an optical drive that has a block-size...
  20. M

    TZ30 / TK50 / CompacTape adventures

    I've been playing around with a DEC TZ30 CompacTape drive this week - so far without much success. The drive itself seems to be working fine. It's installed in a MicroVAX 3100 Model 90 running VMS 5.3. It seems to be a fairly robust design - no rubber rollers anywhere in the tape path, and no...
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