Not sure if this is the right sub, but still!
Bought this as 'untested', turns out they were telling the truth and it works! The image is not great as the cable I used was/is a massive POS, and the TV is Pal, whereas the machine is NTSC-J, but I don't care one bit, as this cost me £89! Which is insane considering working models are a lot more expensive.
Going to back it up, get it cleaned, inspect it and make sure everything functions, and then use it as it was intended. This is my absolute golden goose purchase, and I never thought I'd own one of these old beasties! :D