Don't see a picture attached...

It is a triac used to flash the GI lighting, a few other games of the era had them like Centaur etc.

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If either the triac or the MOC 3011 short then you could lose GI lighting. From the games that have come through the shop here, my experience has been more with failed MOC 3011's than the triac. Both parts are cheap and available so you should get things up and running quickly if you find a problem.