9 Slot S-100 Bus 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.
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.
A new V4 version of this motherboard has been fabricated. Please contact Josh,
AKA "Crusty" here
to see if one is available.
Also read here
for a description of a similar 12 slot motherboard and
here for an advanced
S100 bus system by Jerffrey Wilson.
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.
Other pages describing my S-100
hardware and software.
Please click
here to continue...
This page was last modified on
08/15/2026
