- Sounds like you might have some buttons that are going bad. Open the unit. Check the to see if the plastic buttons for bank A and B are making contact with the actual tact switch. When the plastic buttons break at the joint, it's harder for the button to make contact with the tact switch. If that's not the problem. Go out and buy a can of Detoxit contact cleaner. Take the plastic button off the PCB board - be careful not to break the plastic legs that anchors the plastic button to the board. Spray couple of times of the detox spray on top of the tact switch and press in the tact button a few times to get it working in there. Cover around the tact switch with a paper towel, so you don't get that stuff spraying all over the place. Make sure the unit isn't powered on while you are doing all of this. Don't put the cover back on until you confirmed if it's working or not. Have fun!
