When I got my Yamaha CA-1010 Amplifier, it worked quite well with the exception that most of the backlight did not work.  I promptly tore it down, checked the power consumption of a working bulb, and replaced the bulbs with LEDs with current limiting resistors.  Also, while inside, I sprayed the controls with contact cleaner (isopropanol based) and followed with silicon lube to stave off oxidization.