Tandy TRS-80 Model 100 Teardown

The drive-side swap was kinda simplistic.. I masked off pin 32 (top-side, furthest from the notch between pins 4 & 6 (all odd pins on the bottom) and ran a wire from both drives, to this pin, with a 1-ohm pull-up to +5V,out to a mini jack through the case front, and the shield of the jack to the GND. Idea being, to change to the 2nd side of the drives, I simply used the command (forgotten, Yipes Old Age is setting in!) to toggle the cassette relay... Just had to remember in the program I was using, to remember which side I was writing to. I actually re-worked one of the basic Xmodem programs, to be able to write binary data in hex to separate files on all 4 sides, for huge binary files.. (used to drive an old RBBS-PC transfer program batty with the delays of writing the data.)

I edited my post of yesterday and it has now disappeared - probably for scrutiny as I added a link to photo's of the Memory mod we made for the 100 in the 80's.

Another thing I remembered of the Radio Shacks and never appreciated it till the IBM PC cam along was that the printer header was laid out as required for the centronics printer plug! So with a length of ribbon cable, an Centronics crimp on plug and a header plug, I could make up printer cables sometimes using a coke bottle as a hammer.

When the IBM PC came out, it was a shock and frustration to make up printer cables - was a real nightmare!

using SCOM to interpret raw printing data to my Zerox 460C typewriter. On my laptop you could see the global characters representing command code in the very documents I was processing. I was elated to find I could use Ctrl keys to insert these commands without modifying the document once it was loaded into the typewriter.

I could work on the PC while my clerk banged away on the typewriter; it made for a very efficient office. I still have both machines, and I just have to rebuild the battery to get the PC going again!