I'm wondering if the 'works with Demo time' isn't a massive red herring, have you switched the ROMs back to see if it still works with the Demo Time ROM? (Apologies if you have, I only skim read the thread)
Before buying anything, I would test 100% every single switch and opto related to the claw operation, if you look in the manual at the switch locations page this will help with that.
95% of the problems I've seen with the claw are to do with the claw opto, due to WMS cheaping out on the opto hardware. I can highly, highly recommend this board if the claw opto board is faulty: