SCELBI 8B Backplane Progress Being Made

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Lately. I’ve been making some good progress on the 8B backplane. Hopefully in a few more weeks and I’ll have it in good enough shape in order to declare it finished. I’ll probably just go ahead and get it made when it’s ready, even though I have a lot of work to do on the other 8B specific cards.

There is quite a bit involved in building an 8B chassis and 8B builders can start on the chassis while I finish the rest of the cards. Anyway the CPU can be checked out by jamming in instructions, without memory being present. The front panel, CPU, DBB, and input boards are completely identical to the 8H design and I still have some of those PCBs in stock.

One thing I’m going to have to think about a bit, is whether to make a batch of SCELBI custom sized chassis or not. A BUD AC413 can be made to work, as it is nearly the correct size, just a 1/2″ short, other dimensions being right on.

Status of the other 8B specific cards are:

  • memory expansion – I haven’t started on this one, but it is the most basic of the 8B specific cards, so should take the least amount of time to do
  • 4K SRAM- designed to accept 2102 static ram – this card is pretty far along, maybe half done.
  • EPROM – designed to accept 1702 EPROMs – I have a tested, working layout for this card done by someone else. The original layout artist did a good job, but there are a few things I want to change. I will completely go through it to make the layout details match the original as much as possible.

    • One thought on “SCELBI 8B Backplane Progress Being Made”

    1. Great work Mike! Really looking forward to building one of these 🙂

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