Build Your Own SCELBI 8H or 8B Mini-Computer

Reproduction SCELBI 8H

Part 1 - See The Reproduction SCELBI Run

See my video of my first power on of my reproduction SCELBI and the SCELBI equivalent of "hello world": http://www.willegal.net/podcast2-2-13.mp4

Reproduction SCELBI 8H, without Front Panel

Part 2 - Reproduction PCBs and Front Panels For Sale

I have laid out and have had made detailed reproductions of the 6 boards needed for construction of a SCELBI 8H mini-computer.

From front to back, these boards are:

Front Panel
CPU
DBB (data bus buffer)
INPUT
1K SRAM
Backplane (bottom)

After testing, I have found two issues:

A minor issue with hole size for some types Zener diodes as documented here on some boards. As I make reruns of boards, this issue is fixed. The current inventory of most kinds of boards have slightly larger holes.
On the 8H backplane, one of the mounting holes for the edge connectors is slightly misplaced. Enlarging the hole solves the issue and since one side is covered by the edge connector and the other side by a nut and washer, this is invisible to anyone closely examining the system.
A missing trace under one of the chips on the 8B memory expansion board, as documented here.

Available PCBs - these are not kits, only PCBs:

SCELBI 8H - basic six board set - $300, includes backplane, front panel, CPU, DBB, input and 1 1K SRAM
SCELBI 8B - basic eight board set - $350, includes backplane, front panel, CPU, DBB, input, memory expansion, 1 4K SRAM, 1 4K PROM board
Extra memory boards are $50 each - available boards include 1K SRAM (for 8H), 4K SRAM (for 8B), and 4K PROM (for 8B
I have reproduction SCELBI TTY boards available for $30 each
A set of reproduction Cassette interface boards is available for $50
A complete set of all 13 boards needed to make up a full, 12K SRAM, 4K PROM, SCELBI 8B, plus cassette and TTY interfaces is available for $475
The keyboard and oscilloscope (analog and digital) interface boards are available as a set of 3 PCBs for $75
Reproduction Digital Group Video Card - 50$

Send email with your shipping destination to mike@willegal.net for detailed information and a shipping quote

After investigating building one of your own, you may come to the conclusion that building a reproduction SCELBI is a bit expensive. You should keep the following in mind:

Original units are extremely scarce. I know of less than 20 original units, almost all of which are in the hands of serious collectors or museums.
When original units are sold, they typically sell for around $15,000

Bare Reproduction SCELBI 8H Boardset Mock Up Chassis Configuration

Part 3 - Parts and Construction Information

Cameron Cooper's website, scelbi.com has available for downloading, all the excellent original documentation needed to build a SCELBI.

Almost all components are easy find to discrete parts or 74XX series digital parts. The exception is the CPU and the 1101 memory chips. American Microsemiconductor has the 1101s:http://store.americanmicrosemiconductor.com/mm1101a-a1n.html. I sell 8008's as a bundle with PCBs or they can be found on ebay.
Original parts list (in pdf format) can be found here: Parts List
Component list (in excell format) can be found here:BOM-SCELBI-boards.xlsx

Eventually I'd like to put together a complete guide to the SCELBI, including everything you need to know to build your own, but for now, read though my blog entries to find out about what it takes to build a reproduction SCELBI. Joining the retro-restore Yahoo group is another way to learn about SCELBI and other retro computers.

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