As with many factory-installed radios, the Grundig 200 model radio, common to many European cars, has a built-in antitheft code. When you remove the radio or disconnect the battery from the vehicle, the antitheft code kicks in and prevents you from operating the radio until you have entered the code. Your vehicle's documentation should have included the code for your Grundig 200 radio.
Turn the accessory power on with your ignition key.
Press the Grundig 200's power button and the button labelled "AS" at the same time. Hold the buttons in until the radio beeps. Release the buttons.
Enter your code by using the radio preset button on the bottom edge of the radio face. Press each of the buttons in sequence to enter the digits. For example, if the first number in your code is "5," press the first button five times until the number corresponds on the display. Then proceed to the second code number, using the second preset button to enter the number.
Once you have entered the numbers, press down and hold the AS button until the radio beeps. Your radio should now work.