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Thread: Ohio Scientific 560Z (PDP-8) Board Clone?

  1. #31
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    Just submitted the artwork to the PC board house! I'm ordering 25 bare boards. Looks like they'll be around $20 USD each + shipping.

  2. #32
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    Ordered a bunch of 9x12" bubble mailers and "DO NOT BEND" stickers today -- expecting the boards in by the end of next week!

  3. #33
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    They're here!









    Side-by-side with the original from which it was copied:



    Boards are decent quality. Not out of this world, but you sort of have to go with cheap suppliers to keep boards this large at a reasonable price. I'll send out preorder emails tonight. Bare boards are $25 USD each + shipping. Shipping in the US is $5 USD, I will ship overseas but I'll need your mailing address to do so. If you didn't preorder and/or you don't get a preorder response email from me in the next hour, please use the contact form to get in touch with me and place your order:

    https://services.theglitchworks.net/ng/messages/new
    Last edited by glitch; February 14th, 2017 at 09:23 AM.

  4. #34
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    Looks like 8T95s for the parts kit are going to be easy -- one of my suppliers has 1800 of them in stock!

  5. #35
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    I put together a spreadsheet this morning while the test suite for $day_job is running. How's a $50 parts kit sound? That of course doesn't include a Z80 or IM-6100. It would include:

    - All TTL ICs
    - 8T26 and 8T95 bus drivers (I probably have enough 8T28s to sub if you use a positive data bus)
    - 4x Motorola MC6821 PIAs
    - Sockets for 8T26s, PIAs, and CPUs
    - 2x NOS Mallory TAS-M tantalums for main power bus decoupling
    - Handful of axial MLCC caps for bypass
    - Misc. resistors, capacitors, diodes
    - 8x NOS Molex KK-156 sockets for MOS and SYS bus connections

    That's with US-made machine pin sockets, I can get them from China for significantly less, but it might knock $10 off the kit price. Add $5 if you need a Z80. I haven't gotten to the point of testing my handful of IM-6100s -- have to finish the 560Z build first

  6. #36
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    IT LIVES!

    I spent most of today hacking on the 560Z board. I got the 12-bit porthole going first, took a bit as the manual doesn't tell you that you need IC CC installed if you want to be able to write to the 4K exposed in the porthole. After that, I plugged in a Z80 and tried to get it running the test code in the manual. Turns out I had a dud Z80 With a good one installed the test code ran no-problem, as did a little hand written code to push data to the lamp register on the new memory board. I plugged in an IM-6100 and pretty much determined that at least the first one I tried is dead. I'll recheck the soldering on it later -- it's stuffed into a machine pin socket and soldered in, since half of the legs were rotted off by that corrosive black foam everyone loves so much.

    Anyway, the second IM-6100 works! And the 560Z board works! And the 12-bit RAM board works! I made a (low-res, poorly focused) video with our old digital point-n-shoot:

    https://www.youtube.com/watch?v=ZYbGXHJST8U

    The IM-6100 is running a little loop that increments the accumulator and stores it to the lamp register. Storing of course clears the accumulator, but I have the lamp register mapped over RAM, so I just read the value back out of it. My first foray into PDP-8 code, it's certainly different, but it's still just machine code. Very happy that this seems to be coming fully together! Now if only I could find more IM-6100s...I'll test the remaining 3 tomorrow.

  7. #37
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