Will not reliably switch or stay latched in piano or synth mode via the select switch. I suspect the light action switch is too light. Easy enough to remove the keycover and inspect the phosphor bronze action. Is it just a matter of cutting back the spine of the keycap a bit , so the action is farther removed from a hair-trigger situation? All clean and tidy inside the switch.
I think cause or part of the problem is the metal casing of the top , containing the switches, has been bent,dished or flexed slightly. The keycaps are then partially compressed by the metalwork. Some padding washers will go in there, as any of the keycaps could be the next affected. Also the wooden end cheeks are loose. Only 2 thin wood screws per cheek , and the wood is now not holding the screw threads. Some bracing plates will go in there with 3 woodscrews extra. Employing the old carpenter's trick of the axis of the 3 screws all angled relative to each other so they mutually anchor themselves in there, also allows longer screws for the relatively thin wood available.
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