So...just like a bunch of folks, my volume knob stopped working (2007 X5 E70). It is "loose." This means it can turn the power on and off, but not adjust the volume.

I removed the radio head and took the unit to a small electronics repair guy. He said if I found a new "electronic volume encoder," he could install it on the circuit board. Or the other option is to buy an entire new circuit board or entire radio head ($ hundreds).

Does anyone know:
1. What company made the radios?
2. Where I could find a replacement electronic volume encoder or entire circuit board?

Thanks!

Tom