Audio Systems: CD Receiver Loses Memory, pioneer deh p47dh, dodge neon

Question
I recently installed a second-hand Pioneer DEH-P47DH in my 95 Dodge Neon. It fits and works perfectly, with one exception.  It will lose all settings (clock, radio, and CD track)after the ignition or accessory power is turned off.  I know that the +12V memory wire is hot and properly connected to the receiver (if I disconnect the memory wire, the unit will not power up at all).  The receiver will hold its settings for about 30 seconds after power is disconnected, but after that they are gone.  My local Pioneer-autorized service center said this situation is unusual, and wants about what I paid for the unit just to evaluate it.  Any thoughts?

Answer
Hello Jerry,
I have seen this before, a small diode that channels the back up voltage to the processor is defective. When the back up wire is connected it allows power to go to the on off switch transistor and the radio will turn on. With the open diode, the memory hold circuit will go dead when you turn off the radio. In several radios I found a shorted capacitor in the memory hold circuit cutting off supply voltage to the hold circuit. I don't have a schematic for this model, so I can't give you locations of the parts to check out.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net