Product diagrams for GC3BA-042B-C Removed 2 screws on side opposite access panel. Heater stopped working. Called a service professional and he replaced the Motherboard.Heater Not working. Can't see what those screws held, but they will not go back in because whatever they held has fallen away, and there is no access to that side of the unit. So what should I do? My service man is coming back, but he is not certain what the problem is, he suggested the motherboard may be compromised even though it is new.