Electronics Repair Questions? Ask an Electronics Technician
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If you've not already done this- please unplug the subwoofer's power cord, and then use a flat blade screwdriver and pop out the fuse cartridge out of the bottom of the AC power inlet and check to see if the fuse is blown or not. If so, then it could be a simple faulty fuse- or could be caused by a larger issue downstream in the amp (faulty output stage, etc.).
In the latter case, it's generally not considered cost effective to make repairs to the plate amp, as it's on the cusp of what a new replacement amp would cost, and it would generally make more sense to purchase a replacement plate amp (at the link below):
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