Shooting from the hip here but could the Frame stepper be getting a brief reset pulse during the game, or maybe a reset pulse at the same time as an advance pulse? You could put a bulb tester across the reset solenoid solder lugs to see if it ever fires when you see the problem.

/Mark

And to you too. Sorry to hear that. You'll want to use enough bulbs in series to cover close to 50 volts or more. For example:
- four 12 volt automotive bulbs (48 volts total)
- eight 6.3 volt game bulbs like 44 or 47 (50.4 volts total)
- one household incandescent bulb (will be dimmer than expected but should work)

You could also swap some bulbs for high wattage resistors if you have them but you'll need to do a little more math. The object is to limit the current through the bulb tester so that neither the fuse nor the bulbs blow.