Re: 1200 baud down, 75 baud up
I used to fix those modems:
Prism 1000\TeleMod2
Prism 2000 (Made by Thorn-EMI 99% of the time it was a failure of the Voltage regulators).
VTX5000 - Spectrum specific.
Voyager 7 or 11 Modems (Also known as Magic Modems & Kirk's Enterprise).
Happy days & much drinking & eating in London during trade shows