SWTPC 69K Computer

SouthWest Technical Products Corp. 69K Computer

I got an email in November 2003 asking if I knew of anyone who wanted a SWTPC 6809 computer with dual 8-inch disks and terminal. The sender, David Banks, had a system that had been in storage since 1987 and did not want to put it in the dumpster. He was in the Dallas Texas area a few miles from my niece. A few weeks later David delivered it to my niece's garage. My brother arranged to have his son ship it to me. The day before Christmas I got about 100 pounds of computer equipment.

The system was a SWTPC 69K that had been used as a development system for a motor control project. To increase the computational speed, AMD 9511 and AMD 9512 floating-point processors were added. The Introl C compiler math libraries were modified to use the AMD processors instead of the 6809.

SWTPC 69K Computer High Resolution Photo

The 69K has 3 Digital Research 16K memory boards, a SWTPC 8K memory board, a wire-wrap Math coprocessor board, a SWPTC 6809 CPU and a SWPTC 8 inch floppy controller. The I/O cards (left to right) are SWPTC dual Serial port, a SWTPC floppy controller, a Music Card, a wire-wrap parallel port, and a second SWPTC dual Serial port.

The black power transformer has a second transformer on top of it. This was wired to boost the input voltage. (I guess the 9511 and 9512 use a lot of power.) The 69K power transformer is smaller than the one in my S09 system.

High Resolution Photo

SWTPC MP09A 6809 CPU board. The address translation RAM circuit has be disabled.

High Resolution Photo

AMD 9511 and 9512 coprocessor board. The 9511 was a floating point unit and the 9512 added transcendental functions. This was a bit faster that the SWTPC MP-N calculator card.

High Resolution Photo