I've got a Twister that's actually in pretty good shape, except for the magnets not working. Sega put out a Service bulletin on a problem with them, # 91. I followed it and got the magnets to work for a couple of games but now they're out again. The bulletin suggested making sure you have the latest code roms; replacing a certain diode on the magnet board with two in parallel; removing a neon bulb and replacing it with a resistor. I also replaced the PAL chip at the same time with one I bought from E-Bay. Since it stopped working again I replaced the PAL chip one more time, but no joy. Fuses seem good so I'm not sure what to do next either. Good luck!