SWTPC Serial Board Prototype

Wednesday, April 16th, 2014

I really liked the SWTPC 6800 based systems of the mid/late 1970s, although a tad out of reach for a high school student.  They came as inexpensive kits and the designs were easy enough for someone with a bit of technical knowledge to understand.  But I never got one.

Well, thanks to having a business making vintage computer accessories, why not just build one from the ground up, using a few modern parts along the way?

The starting point is a serial board that’s basically the same as an MP-S card:

SWTPC_Serial_1This is the first prototype, so it’s got some clean-up work coming still.  It’s got a MAX-232 instead of the old 1488 and 1489 chips, and does not have 20 ma current loop nor cassette clock in/out.  What it does have is a DB-9 on the rear panel and more options for picking up the baud rate from the user defined pins like many people did back then.  It uses a standard SS-30 bus so it can plug into a real vintage SWTPC machine and operate.

The wires are temporary connections to a 6800 based breadboard.  It’s not a pretty sight and is only for testing the serial board and trying some experiments for the next few SWTPC compatible boards.

It’s got one circuit error and I’m going to put a Molex connector on top so it can completely replace an MP-S.

I need a beta tester!

Yes, someone who has an existing SWTPC system (operating, of course) who can take a prototype board, plug it in, and verify it works.  Someone on the East Coast, preferably close to NJ, would be best but I’m flexible.  If interested, email me!


Vintage Computer Fest 2014

Saturday, April 5th, 2014

I’ll be at the Vintage Computer Fest in Wall, NJ today and tomorrow.  If you go, stop by and say hello at my exhibit.  Look for the collection of Franklin Computer systems.


KIM-1 60K RAM Boards are Finally Here!

Wednesday, March 26th, 2014

This project has been a long time coming, but finally here!

Is the KIM-1′s default 1K of RAM too small?

Our 4K board still isn’t enough?

Then how about 60K???


This board adds 4K from $0400 to $13FF, then another 56K from $2000 to $FFF7!  Now you can run those really big programs like the FOCAL and full featured BASIC interpreters out there on various web sites.  The memory can be disabled in 8K blocks, but who’d want to disable any of it?  Oh, and with a bit of cutting and jumpering, you can even add another 60K (120K total) to the board ;-)

The price is $69.95 and includes the 10 in cable to connect it to our I/O board, but you can wire it to your KIM without the I/O board.