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Thread: H11, H27, and WH14 Cluster

  1. #1
    Join Date
    Mar 2017
    Location
    Pennsylvania, New York
    Posts
    34

    Default H11, H27, and WH14 Cluster

    So recently I purchased a group of items. a H11, a H27, a WH14, and an arbitrary keyboard, all from the same person. I assume that they also had the same original owner. So after shipping, which was, of course, rough, somehow all of the cards had become unseated. Thankfully the owner had numbered the right columned cards, starting with the processor, which was still seated. So I put the numbered cards back in the QBus in their original order, I wasn't sure of the other ones, but because of how they fell out, I think I put them back correctly. From what I can tell, there are two serial cards, the processor, two ram expansions ( one Heathkit and one DEC) a floppy card and a mystery DEC card (page 22). The serial cards had a bunch of jumpers (neither of which were setup in the default Heathkit options for the terminal or printer) which are shown in the PDF. I would assume that one of them was used for the printer, but I don't know which. the ram cards have a relatively obvious function, and I included a picture of the jumpers in the pdf attached. Now, I'm having a few problems. First and foremost, the floppy connector coming out of the computer is a standard 24 pin connector, but the wire in the slot of the H27 is a 34 pin connector. Obvious issue. Is the floppy card meant for like an RX50 drive, or do I need an adapter card? Second of all, I would like to hookup the printer, but it uses some dsub connector, which obviously doesn't fit the 24 pin connector for the serial port on the back. Thirdly, the keyboard has an RJ11 connector, and I assume the whole assembly was used with the printer serving as an output and the keyboard and floppy drive as an input, but there's no obvious way to connect them. Are the printer and keyboard just randomly thrown in and not related? I also have a blank serial card which I hope to connect to an H9, which is a whole other issue, but I want to know if I were to remove a serial card, would any modifications to anything else be necessary? I am trying to make sense of this seemingly random concoction of things which I now own. Any help is seriously appreciated.
    Thanks,
    Harper

    The PDF was too big, so here's a link to it:
    https://drive.google.com/file/d/1rou...ew?usp=sharing
    Key for PDF:
    Serial Card 1 (jumpers) - pg 1-7
    Serial Card 2 (jumpers) - pg 8-12
    16x16 Memory (address) - pg 13-14
    Main LSI-11 (jumpers?) - pg 15-17
    Mystery DEC Board - pg 18-21
    Total Arrangement - pg 22

  2. #2
    Join Date
    Nov 2014
    Location
    Chicagoland
    Posts
    154

    Default

    Quote Originally Posted by Gfbtdhg1 View Post
    So recently I purchased a group of items. a H11, a H27, a WH14, and an arbitrary keyboard, all from the same person. I assume that they also had the same original owner. So after shipping, which was, of course, rough, somehow all of the cards had become unseated. Thankfully the owner had numbered the right columned cards, starting with the processor, which was still seated. So I put the numbered cards back in the QBus in their original order, I wasn't sure of the other ones, but because of how they fell out, I think I put them back correctly. From what I can tell, there are two serial cards, the processor, two ram expansions ( one Heathkit and one DEC) a floppy card and a mystery DEC card (page 22). The serial cards had a bunch of jumpers (neither of which were setup in the default Heathkit options for the terminal or printer) which are shown in the PDF. I would assume that one of them was used for the printer, but I don't know which. the ram cards have a relatively obvious function, and I included a picture of the jumpers in the pdf attached. Now, I'm having a few problems. First and foremost, the floppy connector coming out of the computer is a standard 24 pin connector, but the wire in the slot of the H27 is a 34 pin connector. Obvious issue. Is the floppy card meant for like an RX50 drive, or do I need an adapter card? Second of all, I would like to hookup the printer, but it uses some dsub connector, which obviously doesn't fit the 24 pin connector for the serial port on the back. Thirdly, the keyboard has an RJ11 connector, and I assume the whole assembly was used with the printer serving as an output and the keyboard and floppy drive as an input, but there's no obvious way to connect them. Are the printer and keyboard just randomly thrown in and not related? I also have a blank serial card which I hope to connect to an H9, which is a whole other issue, but I want to know if I were to remove a serial card, would any modifications to anything else be necessary? I am trying to make sense of this seemingly random concoction of things which I now own. Any help is seriously appreciated.
    Thanks,
    Harper

    The PDF was too big, so here's a link to it:
    https://drive.google.com/file/d/1rou...ew?usp=sharing
    Key for PDF:
    Serial Card 1 (jumpers) - pg 1-7
    Serial Card 2 (jumpers) - pg 8-12
    16x16 Memory (address) - pg 13-14
    Main LSI-11 (jumpers?) - pg 15-17
    Mystery DEC Board - pg 18-21
    Total Arrangement - pg 22
    Though I don't own an H11, I'll try to answer or give feedback to your questions above.

    I don't have any insight into the mystery board. A set of full pictures for this board, both front and back sides, would be useful in researching this.

    There should be enough documentation on-line to help you check or reconfigure most of the jumpers on the boards. They do look a bit haphazardly wired. Glad to help if you stuck. Since you have two serial cards, you should be able to implement the TU58 emulator as a set of disk drives if the floppy don't immediately work. One of the cards should set for console at address 177560. You can remove unused card(s), see the WH27 manual below for the recommended placement.

    The terminal should typically connect to a DB-25P type connector cabled to the serial card. Suggest you connect this either to the H9 or to a PC running a VT100 emulator with a usb/serial convertor and 25/9pin adapter. RJ11 type connectors were not originally used in equipment of this era. The ODT (online debugging tool) on the cpu will allow manual examination of memory, registers and key in small code in octal. The PC method (on Windows) enables the use of the PDP11GUI see http://retrocmp.com/pdp-11/pdp11gui

    For the floppy system and cabling, there are three major components. The floppy drive itself should be industry standard (see Shugart 850) with a 50 pin connector with electronics to control the motor, stepper, head loading and read/write analog head signals. From that drive, internal to the floppy cabinet there should be a drive controller with a 50 pin input from the drive(s) and 34 pin output to the H27 Qbus card. This controller will have the control registers implemented on it, a cpu for management and does the decode/encode of the data from the signals received/sent from the drive. The H27 card is basically just a 8 Bit parallel I/O card to QBUS interface. So an RX50 won't work directly with the H27 card.

    See Alan Baldwin's site for a manual for the floppy disk system - http://shop-pdp.net/~stuff/PDFs/Heat...isk_System.pdf. Alan's site has other Heath manuals of interest as well.


    Jerry

  3. #3

    Default

    Thanks to wa2flq for the link to the WH27 manual. Many people, including myself, get their H11/H27 without any documentation.

    I did however get my H11 with the cards removed from the card cage, put back into their factory anti-static bags, and put back an in the original Heathkit box. The anti-static bags have labels showing where they go into the somewhat confusing Heathkit backplane. Mine is a two switch H11. There are some differences between the H11 and the H11A.

    From the labels:

    M7270 - LSI-11/03 CPU with Floating Point option
    Use in 18 bit backplanes only. (solder side up)
    Install this board in the First slot:

    M8944 - DB 32K Words (64Kbytes) RAM
    Use in 18 bit backplanes only (solder side up)
    Install this board in the Second slot:

    H27 Floppy I/O Card
    Use in 18 bit backplanes only (solder side up)
    Install this board in the Third slot:

    H11 Serial I/O (Console)
    Use in 18 bit backplanes only (solder side up)
    Install this board in the Fourth slot:

    Note the "solder side up" on all four boards.

    Note also that the backplane is laid out strangely

    The slots are numbered like so with the card cage/backplane raised up on the hinges & looking at it from the front of the H11:

    2222222222 1111111111
    4444444444 3333333333
    6666666666 5555555555
    Empty Space
    8888888888 7777777777
    "It's all bits on the bus, Cowboy! It's all bits on the bus!" -- Tom Beck, #1ESS Instructor, Southern Bell Opa Locka Training Center

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