[Ron Ramirez]

Sean raises a great point. You have to be sure the pins of each loctal tube are clean. You should also clean each loctal socket pin as well. DeoxIT sprayed into each little pin hole of each loctal socket, followed up with one of those small brushes such as designed to clean between teeth, works well.

I had mentioned mica caps earlier. Yes, they can and do go bad, and if all else fails, they may still require replacement.