Hjalfi almost fixes a TRS-80 CGP-115 pen plotter

In which yr hmbl svt achieves unparallelled levels if incompetence by nearly wrecking a 40-year old plotter in an attempt to get it working again. So this is a classic plotter, based on an ALPS off-the-shelf plotter mechanisms which was reused in a dozen 1980s plotters: it draws multicoloured images on paper by physically drawing on it with four neat little ball point pens. This was almost mint in the box, but turned out to be broken when I tried powering it on. Identifying what was wrong was... more complex than I thought. I did eventually bodge it into submission but it was a close thing. I really must find a budget desoldering gun. Everything you ever wanted to know about these plotters can be found here: http://tandy.wiki/CGP-115 (except where to get replacement stepper motors...) Production notes: sorry about the hiss (I normally run the audio through a denoising filter but it made my renders crash this time), the boominess (not having much luck with the microphone position), and the colour balance (bah).