I have a few 740 radios that all tend to loose the station presets when it gets hot. Afterwards the FM band is reset to the bottom of the frequency range which wouldn't be all that bad except that there's nothing there that I want to listen to. Does anyone have any electronics backgrond who can tell me which chip or component may be involved in saving the station presets? I'd like to try replaceing it unless it's the mega-pin (50?)IC on the circuit board. Or maybe there's a small battery somewhere that can be replaced?? I know I should just get an after market unit but I have this uncontrolable genetic thing that makes me want to fix stuff rather than throw it away.