My 1993 BMW 325i radio turns on, but after a few minutes fades to no sound. Turn it off for a several seconds and comes back on but quickly fadws out again. The same for the CD player and all radio bands. Almost like a resistor or capacitor is heating up and failing. Any ideas?

-press and hold the left instrument cluster button
-at the same time turn the key from the off position to the first position (just until the radio lights up, if the check engine light comes on you have gone too far and need to try again)
-after a couple of seconds the display around the odometer should change and say insp or os reset at that point let go of the button and press and hold the button again
-when the word in the odometer area starts to flash let go of the button and just press it like you would if you were resetting the odometer
-at this point it should say end turn the key off and back on again to see if you were successful (it may take a few tries before you get it)