Alpine 7521 Reset Code?

Swanson17 New member Username: Swansonmotorsportsgmai... Spring Hill, Tennessee United States Post Number: 1 Registered: Apr-24	Posted on Tuesday, April 16, 2024 - 16:24 GMT I just got a new classic car and the battery went dead. Now the Alpine Radio says CODE on the display. Were can I fine this code? Its a older Alpine 7521 I think the ser # is R31026768A. Any help is appreciated.
patgrobbendonk New member Username: Patgrobbendonk Post Number: 3 Registered: Apr-24	Posted on Tuesday, April 16, 2024 - 21:05 GMT can you see a sticker on the under or upside with barcode or info