That sounds like his fix (on the pb160 at least) is replacing a "40v supply" - does this mean the caps on the inverter board in the LCD assembly? Even if they look ok? Or do I misunderstand what he means ?

As a last resort - If I replaced the motherboard and LCD with one from a 540c or 520b/w would that work or are there other parts that would need need to b swapped as well?