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Dead BOSE PS28 III subwoofer (no sound) repair

This Bose subwoofer doesn't activate , Media center and display work. the matter may be a a fault on the facility supply board inside the subwoofer.

Please be reminded that each repair is exclusive . However , if one among the MOSFETs shown during this video is flawed likelihood is that you'll be ready to repair it with these instructions.

I get my parts mainly from
The power Mosfets are during a TO220FP package, if not available you'll choose similar types, important parameters would be VDSmax, Idmax, total gate charge.
The diodes are during a SOT23 package, any fast small signal diode will probably do.
Resistors are available a 1206 package.

The two big capacitors 470uF/250V (LGU2E471MELA from Nichicon) should get replaced too, that they had their ESR increased by 35% and 15% loss of capacitance compared to new ones of an equivalent model.

If you do not have power on the controller chip (pin 12) there may additionally be the 2 SOT23 components damaged, one among which may be a zener diode 13V, the opposite an MMBT3904.

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