05-18-2009, 10:06 PM
I've done some electronic troubleshooting but until I get a moment to gather my thoughts here are some additional notes.
Pushbutton maintenance: The pushbutton switches were not functioning well mechanically. Those I could depress would locked in place. To get a better look at the assembly of eight buttons I removed the switch carriage and coils carefully from the tuner frame, taking great care to avoid any tension on the wiring. A very soft natural hair paint brush was to clean any of the dust on the coils and switches that I could not blow away with my breath. I did not use compressed air. Too may fine wires. Once that was done it was time to loosen up the switches. One drop of Marvel Mystery Oil on the contact surface and points that move did the job after cycling through the buttons perhaps a dozen times. The excess was removed either with a paper towel or cotton swab. The contact points looked varnished over so broke off the tip of a swab and twisted a pinch of 0000 steel wool on the bare end. A drop of Marvel Mystery Oil was added for lubrication. All exposed contact surfaces were cleaned well. Any that I couldn't reach were cleaned using strips of 400-grit SiC wet-dry sanding paper. Reassembly was painfully slow but in the end the pushbuttons work as they should. Smooth motion to depress and lock as the previously depressed button unlatches. The only loss encountered was due to age. I beleive there are small rubber pads that would cushion that shock as buttons retract. Age and heat has allowed those to degrade.
Pushbutton maintenance: The pushbutton switches were not functioning well mechanically. Those I could depress would locked in place. To get a better look at the assembly of eight buttons I removed the switch carriage and coils carefully from the tuner frame, taking great care to avoid any tension on the wiring. A very soft natural hair paint brush was to clean any of the dust on the coils and switches that I could not blow away with my breath. I did not use compressed air. Too may fine wires. Once that was done it was time to loosen up the switches. One drop of Marvel Mystery Oil on the contact surface and points that move did the job after cycling through the buttons perhaps a dozen times. The excess was removed either with a paper towel or cotton swab. The contact points looked varnished over so broke off the tip of a swab and twisted a pinch of 0000 steel wool on the bare end. A drop of Marvel Mystery Oil was added for lubrication. All exposed contact surfaces were cleaned well. Any that I couldn't reach were cleaned using strips of 400-grit SiC wet-dry sanding paper. Reassembly was painfully slow but in the end the pushbuttons work as they should. Smooth motion to depress and lock as the previously depressed button unlatches. The only loss encountered was due to age. I beleive there are small rubber pads that would cushion that shock as buttons retract. Age and heat has allowed those to degrade.
