Blaupunkt is a German company that makes high-end audio equipment for automobiles, including amplifiers, speakers, radios, cassette decks, CD players and mp3 players. While major repairs to car audio equipment should be left to a qualified professional, particularly on expensive audio systems, there are some things you can do to diagnose the problem. In some cases, simply knowing the problem will allow you to fix it almost immediately without professional help.
Remove the audio faceplate or media input device in your dash or in the boot of your car, in the case of an in-boot audio system like a CD changer. In most cases, this can be done using your hands or a simple screwdriver. Don't pull too hard on the device, as this could disconnect audio cabling, which may be very difficult to reconnect.
Check that the audio cables plugged into the input device are firmly in place. If not, plug them in and test the device before moving on. Loose cabling is a fairly common cause of intermittent operation in car audio systems.
Inspect the speaker connections in the boot of your car. You may not be able to inspect in-dash speakers without significant technical experience. Make sure cabling is not disconnected or frayed. This is particularly important if audio comes in and out seemingly randomly.
Remove the faceplate of your Blaupunkt audio equipment in the dash of your car or the in-boot system. Check inside for jammed media like a CD or cassette. In some cases, Blaupunkt devices can stop working or work intermittently if media is stuck in the player.
Open the fuse panel where power fuses on your car are located.
Locate your car owner's manual to find the fuses that control your radio's audio output.
Remove the fuse or fuses and visually inspect them for cracks in the filament. In some cases, fuses may be fully blown, giving them a dark grey or black colour around the glass tubing and silver contacts.
Replace the damaged fuses with the same type of fuses. Close the fuse panel and test your audio device and radio. Blown fuses are an extremely common problem resulting in low audio output.
Do not make any repairs that you are uncomfortable with. There is a risk of electrical shock when working on most pieces of car audio equipment, and you could potentially make the problem worse.