Played about 10 games on MET (PRO) in a row. Mid ball, Flippers stopped responding and balls drained.
Within about 15 seconds I noticed an electrical odor. Shortly after that I observed actual smoke coming from behind the playfield. Immediately shut down the game, pulled the translite and raised the playfield.
Turned the game back on, heard 2 arching noises but could not decipher where they were were coming from exactly.
Popped open the coin door as I assumed it was coil related as the flippers stopped working.
Observed proceeded with Coil Test (none would activate) even when holding the coin door interrupt in. Closed coin door and confirmed that F-10 (LED) is NOT on.
Obviously I'll have to replace the fuse, but before doing so I'd like to diagnose what caused the failure to begin with. My guess is it is a coil that perhaps locked on. I attempted to visually inspect the coils and associated connections and cannot determine which may be the issue. On a side note I did rebuild my stand up target assembly earlier today and all seemed well with it but I cannot eliminate it as the potential problem.

So my questions to you folks is where to begin? How do I test or determine if it was a specific coil? Secondly, I'm assuming I need to start testing resistors on J6/J7 part of the driver board with a DMM to determine if one of them failed (again, a guess). Open to all suggestions and thanks in advance. (I'd call stern but it's after hours)

After digging further, the coil wrap on Sparky looks like shit and I'm fairly certain that sparky is my issue.
Having said that.....why would he fail or lock on? Resistor issue?

After searching through some old threads I think I have it narrowed down to the single transistor board located beneath sparky. Seems other pinsiders have had the same problem a few times after digging through old threads. Having said that I have ordered a new transistor board and coil to replace and see how it works.

Thanks LTG.