Next question regarding unlocking radio. I have a '91 Cabriolet with a Heidelberg VII radio. The radio appears to be unlocked (thanks to the code provided by veedubster) but there continues to be no sound. When I turn the radio on I get a low bass popping noise that seems to indicate the speakers work, but no sound coming out when I play the radio or tape deck. The fuse on the back of the radio is good. Other suggestions would be greatly appreciated.