David,

    This is an anti-theft feature. Anytime the power is interrupted it is
supposed to lock up.
    When new it came with "OOOO" or "1234", as it's code. Different models
would come on showing "CODE" or "SAFE" on the screen. The owner would then
enter his own secret code.
    If you lost power, you had three attempts to enter the right code, or
the radio burn the chip, lock up, requiring factory repair.
    The VI and later radio's were matched to the VIN number of the car. So
if you bought it from a salvage yard, get the VIN number and call the dealer
parts department with it and they "can" (if they will) give the code. They
are not supposed to give it to anyone but the car's registered owner.
    I have seen a lot of radios that were never coded, so try to enter
"OOOO" or "1234" and it may fire up.
    The reason yours still works showing "CODE", or "SAFE" on the screen, is
it may be a remanufactured radio, with a bad lock up chip, or no chip. Look
on the part number tag on the housing. If it has an "X" at the end (for
exchange) at the end it's a "reman".
    I always liked those radio's, no CD, and a little simple by today
standards, but they played good, and had some nice features, like repeat and
search on the tape deck.

Cheers

Howard

Subject: Heidelberg Radio - Code?
>
> The radio powers on and  works fine, so when/why is there a need for a
code?