Category Archives: Drastik

Drasktik working on Model 1


The Model 1 is reporting 48k memory without a DRAM in sight. Only two solder wires required, plus adjustments to the two sets of jumper pads which I have replaced with DIP switches for ease of testing.

I’m still working on the solder-less 16k upgrade. May not be possible. Will look at this tomorrow (maybe).

Two minor issues with the board. Seems I can demux 14 bit DRAM addresses but have forgotten how NOR gates work. 🙂

Also had to rewire the keyboard cable as the janky job performed by the previous owner died when I opened the case.

I’ve also 3D printed some replacements for the rubber-ish board standoffs that crumbled to dust when I flattened the boards. If anyone wants the files, let me know.

Static RAM for TRS-80 and System-80

I’ve designed a board that allows replacement of the 8 x 4116 on the Model 1 or System 80 (aka Video Genie) with a single static RAM.

It also allows an upgrade to 48k with no extra parts. A similar board for the Model 3 and Model 4 will follow, with support for up to 128k.

I’m finishing up the board design now. The System 80 has weird spacing on the DRAMs, so I have to adjust the board to accomodate.

I’m trying very hard to get the gerbers out to PCBWay this week. Finger crossed!