S100 Computers

HomeS-100 Boards HistoryNew BoardsSoftwareBoards For Sale
ForumOther Web SitesNewsIndex   
S-100 Motherboard
This S-100 backplane is an 9 slot active terminated motherboard for building and/or repairing small S-100 systems.  It is primarily intended for bench-top work to repair and/or build boards without risking valuable legacy S-100 chassis.  The builder supplies their own power supplies, connectors, and other components.  The S-100 prototyping boards are $32 each plus $3 shipping in the US. 

This board is a copy of an 8 slot  board (shown below) done by Andrew Lynch a number of years ago but with added features.
Added features:
    • 9 SLOT (One more slot added)
    • Active Termination (copied from v 03)
    • 1st SLOT is spaced 1” from other slots to accommodate IMSAI Style chassis. All other slots are spaced the usual 0.75”
    • Mounting holes for ALTAIR and IMSAI chassis. Hole size 0.138” (6-32 screws).
    • Two power connectors with different pin outs.
            o P1 with 0.2” (5.08mm) spacing. Hole Size 0.060”
            o P2 with 0.156” spacing. Hole Size 0.065”
    • Expansion Connectors with multiple function
            o Expansion IN/OUT
            o Test point
            o Active Termination
    • Jumpers to ground some S-100 pins as needed by IEEE-696.
           o Pins 20, 53 & 70. (Pin 53 on ALTAIR and IMSAI computers is needed for Front Panel operations and should not be grounded
             when using these front panels).
    • Thick board, approximately 0.100”.
    • S-100 connectors require 0.25” row spacing. Hole sized 0.040”.
    • Fused power.
  First S-100 Motherboard   First S100 Motherboard-3
A new V4 version of this motherboard has been fabricated. Please contact Josh, AKA "Crusty"  here to see if one is available. 

Note that often S100 motherboards and boxes appear on eBay at very reasonable prices. These motherboards have "no moving parts" and are often a quicker/simpler solution to building an initial S100 bus system.  A good place to look is here.

The relevant KiCAD files for this motherboard can be downloaded from the link at the bottom of this page.

Here is a S100 bus label that can be used as a template on the edge connectors using Avery® Clear Shipping Labels with Easy Peel® 7665 - 8½" x 11" labels. (Provided by Josh Bensadon).

The links below will contain the most recent schematic of this board.
Note, it may change over time and some IC part or pin numbers may not correlate exactly with the text in the article above.

 (V4 3/8/2017)
(V4 3/8/2017)
Most current KiCAD files for this motherboard   (V4 3/8/2017)

Other pages describing my S-100 hardware and software.
Please click here to continue...


This page was last modified on 03/08/2017