A while back I commented on another thread about ageing electronics in historic cars, especially the stuff from the 80s and early 90s. Had a chat yesterday with a gent who has made his living for the past 20 years reverse engineering complex electronic systems. He's made ignition modules for several 70s/80s motorcycles and even replaced the stepper motor systems that re-aim the headlights in real time on porsches.
To build something that replicates the original, he needs an original that's sacrificial. it's not always successful, but he can comment on the difficulty of any particular part once he sees it. A yamaha igniton module he disasembled had the potting compound filled with silicon beads, making it almost impervious to mechanical removal. Some manufacturers scrub the part IDs off to make figuring out the schematic more difficult.
Cutting to the chase, if you need an old electronic device fixed or copied, PM me and I'll hook you up. I;m not taking a cut or anythng, just want to see the stiff back on the track!.