dB Technologies Powered Sub with a destroyed Processor Board. dB would not help so I did as I usually do, reverse engineer the board, because I can.
I think U3 has a headache! The supply rails were down to ground and someone had removed three exploded SMD components that were 100uH chokes and fitted wire links in their place! New 3.3v Buck regulator, and all the dual and quad preamp linear section chips had to be replaced along with vaporised components around them. It has been returned to the customer in a fully working condition. The board is not available from dB so that is why I repaired it.