I bought a 1993 240 with an aftermarket stereo installed. When the ignition is turned off, the radio loses it's presets. So, when you restart the car, the radio defaults to some (non) station and all the presets are lost. It seems to me that the aftermarket radio must rely on a very small about of battery power to run the clock and maintain the settings while the car is off. Perhaps the original Volvo radios did not require any power.

Any ideas would be appreciated.

Bob