Thanks Harald, I saw that while searching.
This seems to be a 3 or more layer board and it’s almost impossible to trace what’s connected to where.
While lit from the underside, I can only see the mains isolation gap.
This unit has been played with before and quite a few trace pads have been destroyed and are non existent. I can rub the solder mask away but since there are several layers, it’s a guessing game without a schematic.
Thank you anyway.
Martin