So, after a bit of a lay-up from various life events that got in the way, I got back to looking at this machine. Desoldered a few resistors from the Input Filter Board and found one of the big 5W 47k resistors had failed open circuit, thought I had found the problem. Replaced the 3 of them that sit in parallel with known good new ones. Still have the input voltage too high error. Still reading over 4Vac where the service manual tells me I should be getting 2.3 (E-E on the sketch). Ive drawn up a little schematic of the board (I think its correct, as Ive said before I am of a mechanical bias), is there anyone in here with the same machine who could stick a multimeter across the various points marked on this sketch (A-A, B-B, C-C and so on) so I can compare to what I am getting. All individual components are within spec so its frying my brain. I think I have seen @Bobbes and @Mustafz have this machine but if there is anyone else who you know of can you please point them to this thread, thank you.