Blaupunkt Flensburg de Luxe Radio 12V

Used Blaupunkt Flensburg de Luxe 12V radio and not working very well. I tested it with 12V and it has rustling sound and it does not find very well all the radio stations. It finds radio stations, but not all and with rustling sound. The knobs are working and both rotary control switches are working. On/Off function is also ok. The size is about 17,5 x 11,5 x 4,0 cm. The radio was made by Blaupunkt Werke GmbH in Germany. It fits e.g. in the old VW Beetle dashboard.