In the subwoofer there is one externally available fuse and two built in fuses which protect symmetrical low voltage supply for the analog path and the amplifier.
The problem was that internal fuses blew immediately after turning power supply on.
This is a D-Class amplifier and there are some descriptions on the web that in this case output filtering capacitors C16 and C17 should be replaced what the owner already did but fuses kept on blowing. I received the Amplifier without speaker housing and took the amplifier PCB out:
Type code of key components on the PCB are removed but it turns out that this PCB is exactly the same as the one used in JBL SCS150SI, SCS160SI and SCS180.6S subwoofers.
The circuit diagram and service manual are available online.
With the circuit diagram available I noticed, that the owner replaced C16 and C17 as they were damaged (you can see corrosion on the amplifier PCB resulting from leaking capacitor's electrolyte) but there were more components requiring replacement, in this case it was Q10, Q11 and Q5. I assume that output filtering capacitor C16, failed to short circuit because of electrolyte leakage what caused Q10 and Q11 to work with a short circuit as a load, this damaged that MOSFETs. Q11 was failed open and D10 failed as a short circuit between gate and drain what caused Q5 to fail. After replacing all three mentioned transistors, the amplifier started to work.
its the same module used in the harman kardon sub-ts11 woofers, those caps are allways leaking all over. also that brown glue is a killer get rid of it anywhere u find it
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