To All:
Since I service all the Mercedes Radio Systems I come across alot of strange things. The knobs that are used on the Becker 1492/1692/3302 or like are made with a rubber coating over plastic. What I did find out about these knobs as to their peeling was that chemicals were being put on them and that it was the chemicals that was breaking down the rubber and the bonding material used. What chemicals you say??? Try, car washes that spray your dash with Armor All or like spray to make it look shinny. Any of these sprays contain Petroleum and other chemicals and the rubber on the knobs is sensitive to these chemicals causing it to melt away basically. So, DON'T let any sprays touch your radio or AC controls or you will be asking for problems.

www.lajollaaudiorepair.com

Cleeve Morrison
La Jolla Audio Repair