Got a quite used HP-10B -- a real one, not virtual or emulated <VBG> -- with some keys not acting as desined: the shift key shows the shift symbol _and_ a "1", a second hit shows 2.7 (from e^x of the shifted 1-key) but the shift symbol stays lit so I may hit the .-key to change decimal point with no need to use shift any more. The INPUT-key makes a 'knatsh'-sound as if it once got some Campari. The ON-key does not work at all.
What's your advice? Worth a try to repair or not?
TIA.....Mike