First up was the task of figuring out what sockets do not make a good connection, and therefore should be replaced.
Open the game door and press the test button and all of the controlled lights will start flashing. With the playfield up, for each one that doesn't blink, I use an alligator clip to jump from the connection of a working light to a non-working one.
If the light does not light then, you know you have to replace it. I replaced about 5 of them.
There are also a handful of lights where the light is rather dim, due to dirty sockets, and I'll probably replace those as well.
Stars uses a single lamp driver to drive both Stars on the playfield: the one at the target, and the same colour at the spinner. Problem is, if one lamp socket is dirty and intermittent and goes out temporarily, the other other will as well. So doubly best be sure the lights are OK.
But now that the bad sockets are located, time to move up the chain to the connectors and the transistors on the light board.