More than once I have seen a foil trace along the front edge of the front circuit board burn and cut the power to the power switch. Not a common failure, but put a meter probe on the exposed pins of the power switch. If you can't see any DC voltage there, something has overloaded that foil trace and blown it like a fuse. Problem is that this trace is on the bottom side of the pc board where it can't be seen. If that's what's going on it's probably only the tip of the iceberg, a casualty of some other shorted part, like maybe a RF transistor?
And if you do show DC voltage at the power switch, the fault is elsewhere.
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