I've been working on an early 1960's United Cypress bowling machine and I am having issues with the light sockets. I cleaned the insides of the sockets and removed any corrosion that would accumulate over the years and I ohmed out the bulbs. I also wire wheeled some of the bulb because of corrosion. The lights do light up in every socket but the lights will dim or not light up after a few games have been played in random sockets. Especially the underside lights for Flash. If you move the bulbs, they will come back on. The bulbs seem to have enough spring tension and should work. Just wondering if there are any tricks to get the bulbs to stay on.
I remember about ten years ago I had the same issue with a 1960 United Falcon bowler and what I did was to slightly squeeze the sockets so the lightbulb would be touching the sides of the socket instead of relying on the little side lightbulb tabs that normally make the contact with the sockets. This worked but I was wondering if there was a better solution than deforming the sockets.