I'm hoping someone can give me a few pointers as to where to go next.
I have a UK PAL Apple IIe with a boot problem. On switch on now there are vertical lines as well as a few coloured pixels. I have replaced the RAM (tested good on another (US) Apple IIe, the CPU (again tested), and the 2 x ROMS (originals were faulty according to my programmer, so replaced with 2764 EPROMS). I have also tested all the socketed TTL, and replaced the 2 x 74LS244 and 1 x 74LS245. The CPU seems to be working, reset goes for Hi to Lo when Ctrl Reset are pressed, and there is activity on all data lines - but this is the best I have got it.
Most of the Apple chips are different between the US and UK boards, so I can't easily swap them out for testing, and schematics I've found on the net seem to only be available for the US board - and I'm not really clever enough to work out exactly what signals I would be looking for anyway!