The Clever Monkey

Retro-computing, the Last Refuge of the Scoundrel

Because I can’t seem to get enough of 1980s high-technology, I’ve decided to attempt to resurrect a TRS-80 Model-100 I inherited years ago. Unfortunately, I made a classic rookie mistake by not properly putting it back together the last time I looked at it, so now I may have misplaced all the hardware that keeps it together.

Assuming I can find the specific plastic 35mm film canister I recall stuffing the screws and other fasteners I removed from it earlier, hopefully I’ll be able to fix it and put it back together enough to surf the web at 300 baud and code in Microsoft BASIC v1.1 (which was authored by some unknown coder who calls himself “Bill Gates”) in short order.

(As an historical aside, I was semi-famous my senior year of high school for using one of these to take notes in class. I may have been the first person in my school to have done this sort of thing. My final grades in Canadian History and English 300 were well above average [for me] that year! I fully admit I did some light BASIC hacking in some of those classes; if those grades suffered, I made up for it in Computer Science 305. [It’s just too bad I was convinced to not go into Software Engineering on Career Day, but that is a story for another post!])

Luckily, there are other folks out there with similar interests such that I was able to get my paws on two different service manuals for the Model 100. Even more lucky for me, it was written with the complete novice in mind, with troubleshooting flowcharts and what-not to aid the technician in finding out why the thing won’t go.

In this case, “won’t go” means “appears to power up, but only displays a bar across a single column of the display”. I’ve already verified some basic voltages and so on, and my fear is that we are on to the part of the manual where I need to start ‘scoping out waveforms. With the oscilloscope I don’t have.

I don’t need any excuse to buy a ‘scope, and I don’t need an excuse to shave more yaks turning my Arduino or my lappy into a ‘scope. But I might have to.

The end goal here is simple: earn the Hack a Day Retro success achievement badge[esc]5Xit-shirt.