Have owned a 1970 Gottlieb flip a card for years and has worked without any trouble. Suddenly it won't start up. When I turn the power on, the 'motor switch' would usually spin one rotation, and all the score etc would reset. Now, the main 'motor switch' spins non stop, and the relay "W Third Chute Relay" clicks at the same rate. It seems to be waiting for something but I don't know what.

Any ideas where to start? I've tried checking the contacts on the parts that are moving but anything beyond that would be a total guess with my knowledge

I have a video but can't post a proper link as I'm new here. You can piece together the address if it helps: sendvid dot com / wxszd0hv

Thanks in advance!!