i have a stereo from an 87 528 in my 76 2002, i got it at the junk yard, got the code from dealer, has always worked after losing pwer from batterey (broken hot wire) just enter the code ba da boom ba da bing. well i replaced the batterey today and now the thing wont work and rejects the code. could it have any thing to do with the quality of the batterey? is there some sort of reset? i mean the thing worked great this morning on the way to the parts store. i even had to enter the code on the way there as the batterey was dead. got there switched batterey started up the car entered the code and nuttin. it just beeps and says code on the display. duh. please help i feel like an idiot.