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Pre-show testing encountered a fault with game PCB. The spare game PCB was swapped in, but the spare didn't boot. Both game PCBs were set aside for repair :(
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On power on the game was stuck at the grid screen. Testing with the Arduino ICT found that ROM, RAM and Interrupt were working OK but reading the control inputs found them to be all zero with no response to control panel or coin inputs. Replacing IC 1E (8255) that handled the game inputs fixed the game.
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After about eight hours of run time on the bench the game was no longer running and displaying snowy picture with no video sync. A power cycle resulted in a blank screen. Connecting the Arduino ICT revealed a failed "Bus Check" with "E:CLK6 Lo 431" that indicated the clock pin 6 was stuck low asserted at line 431 in the code. Using a scope to check IC 7A (LS368) output pin 7 found an active clock. IC 7B (LS107) output pin 5 was idle low. In fact, all of IC 7B was idle except for input pins 9 & 12. Replacing IC 7B (LS107) fixed the game.
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Play testing found the sound slightly off. Connecting the Arduino ICT to the sound PCB this time and running the AY-3-8910 custom tests found IC 3D (AY-3-8910) outputs A,B,C variably bad versus IC 3C A,B,C that seemed OK. Replacing IC 3D (AY-3-8910) fixed the sound.
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There were two issues - bad graphics and the only sound was a single stuck tone. Starting with the main PCB, the Arduino ICT running "RAM Check All" reported "E:1G 4002 50 10". It's lower nibble companion RAM passed OK. Replacing IC 1G (2114) fixed the main PCB and the game played OK but still had bad sound.
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Moving on to the sound PCB, the Arduino ICT running "RAM Check All" reported "E:6D 804d e0 f0" and "AY Check" reported "E:AY3 0004 7B 7f". There was also no audio output from IC 3C (AY-3-8910). Replacing IC 6D (2114) fixed all all the ICT sound issues and the game ran fine on the bench for several hours.