"hobby electronics made professionally"

My 1st Homebrew Computer build for S100 platform.

Note this sections describes my progress in building and bringing up my first computer based on IEEE-696 standard. The S100 comes from the name of the 100-pin bus connector which is used on the computer backplane (or motherboard as some call it). you may also want to look in "Interfacing to S-100 / IEEE696 microcomputer" book which is the "bible" for all S-100 enthusiasts.

This system I am building is inspired and based on S100 cards designed by author of the s100computers.com website which is great source of information for those of you who plan to share this very interesting journey starting from the "roots" of the homebrew computers ending with advanced cards that website author designed & built. I would like to thank the author for all the highly valuable work resulting in tons of information he provided on his website listed above. 

There is also a great community of S100 computer users who have collected and/or built their own machines throughout entire history of S100 specification which stretches 1983  when it was conceived and documented. You can find it here under S100Computers Google Groups. This is closed group of members so in order to be able to read and participate in posting you must join the group by submitting your inquiry to its administrator. 

History & Resource for S100 Computer platform. 

This is great story that I am not even going to try to summarize, instead I encourage you to take a time and read information about it in Wikipedia

My S100 adventure started when I found s100computers.com website. There is also a great source of informaiton including documentation of the S100 dedicated boards available on retrobrewcomputers.org website.

Collecting PCBs for my 1st S100 computer.

There are so many boards available or S100, old as well as new ones professionally designed and built by author on s100computers.com website. 

Fro this wide variety I have decided to build x86 based system which is directly aligned to PC architecture I have been exploring and using for numerous projects in past almost three decades of my amateur then after graduation professional career. 
For this I have collected the list of S100 compatible boards I plan to procure and build which contains the following pcb's:

* S-100 9-Slot Motherboard v4, described here
* S-100 8086 CPU Board, described here
* S-100 4MB SRAM Board, described here
* S-100 Dual IDE/CF Board, described here
* S-100 Console I/O Board, described here

In order to run MS-Dos in the system I also need:
* S-100 MS-DOS Support Board, described here

And to test & adapt my VGA51 ISA version graphics adapter I need also two additional boards:
* S-100 ISA to s100 Adapter Board, described here
* S-100 Prototype Board, described here

Thanks for board stock availibility that can be checked here as well as generosity of some S100computers Google group members - Big thank you Guys! - I have been able to collect all the above and now it is time to start the parts procurement and build.


As most of the boards I am planning to build are recently designed, finding BOM's should not be a problem. I was able to track most of these on the websites listed above. Some, like S-100 Motherboard comes in different flavors and each one in several revisions and optional circuits to be populated, so this particular BOM had to be put together in a form of spreadsheet to reflect my build. Which in my case is fully populated and terminated 9-slot v4 Motherboard. 

I think some of you may find this BOM I created quite handy if you plan to build the same SKU of the v4 motherboard described here and here

For this and all other boards I have included in my system build, you can download my BOM versions here:

* s100 Motherboard v4 - by clicking here  
* s100 8086 CPU board v2a - by clicking here 
* s100 4MB SRAM board v1 - by clicking here
* s100 MsDOS Support v3a - by clicking here
* s100 Dual IDE/CF v3 board - by clicking here

And two additional BOM's which I was unable to find anywhere, hence redone from design schematic and printed circuit boards: 

* s100 ISA to S100 Adapter -  by clicking here
* s100 Buffered Prototype board - by clicking here

All above BOM's has been cross checked to list most up to date (as of 2/24/17) active and in stock components in 99% available from Digikey. Just handful of parts (mostly older) had to be ordered from other vendors like UTsource.net (74LS154, HT6542B) or even eBay (8086-2CPU, M82C84A-2, UM82C88, TIL311, 74LS01). The plastic s100 boards "ejectors" surprisingly found to be available at Mouser.

The entire S100 system in my configuration containing all 7 boards listed above consist if over 1,060 electronic components. That is lot of soldering so if you know friendly electronics pcb assembly shop with working “solder wave” maybe it is good idea to ask them for quote to run all these boards through the wave which guarantee high quality uniform soldering of all the through hole components. And it saves tremendous amount of time assuming the shop is within the reasonable distance. Still, all parts have to be hand placed on the board with discrete parts leads trimmed to ensure proper bridge free solder. If you plan to use shop wave to solder your boards, it is good idea to call them in advance and ask the requirement for trimming the leads to avoid problems later when you bring the populated boards for wave soldering. For the rest including myself, I am going to take time to solder these boards myself using reliable soldering station I use for years from PACE.  

Questions, comments - please visit my Forum

To be continued...


[this page is being updated, thank you for your patience and please visit me again for the update]