1: If the front doors or rear window dash speakers are not working correctly, then there are a problem with ASK unit.
2: If the subwoofers are not working, then there are a problem with Logic 7 amp subwoofer channels amp.
3: If the rear doors or front center speakers are not working, then there are a problem with Logic 7 other two amps responsible for those speakers.

I bought my 2002 E65 a while ago, with only rear door speakers working. So as I have allmost ten years practics in repairing proffessional audio and video equipment I decided to pull the ASK and Logic7 out.
The tricky and complicated part is how to remove old amp IC-s and resolder the new ones wires. The person who does that should very good soldering skills and understanding
how to not damage the circuit board tracks. It is time consuming when doing it correctly. The repaired amps last longer because of the better cooling conditions with new amp IC-s.
I have repaired them with six months warranty and returned non at the moment, sent back only 2 because problems with digital circuit board, in there are some parts not replaceable, then game over with logic 7.
ASK module amp repair-150 EUR
Logic 7-subwoofer channels repair 200EUR
Logic 7 rear door and center speaker channels repair 150EUR
Also aks for CCC repairs.

The customer should send it to Estonia, we repair it in 2-3 days and send it back free of charge everywhere in EU. Do not hesitate to contact alari@karusoo.ee

Best
Alari