If you have successfully reset the device but are now greeted by a "SECURITY" or "CODE" prompt, you have triggered the anti-theft protection. This is different from a factory reset.
If you do not have the card with the code (often found in the glovebox manual): grundig gx3800 factory reset code fixed
If you are locked out of a Grundig GX3800: If you have successfully reset the device but
If you have tried 9876, the hardware pinhole, and the key combo, and the device still says "Code Invalid," your device has corrupted EEPROM memory. This is a hardware logic issue, but it is fixable. This forces the CPU to reboot from a
If neither code works due to a deep freeze, the GX3800’s internal microcontroller might be latched. Here is the hardware fix:
This forces the CPU to reboot from a cold-start state, often reviving units that were deemed “bricked.”
If the method above didn't work, your specific unit might utilize the "pinhole" reset mechanics often found on these chassis: