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Default Yamaha Stagepas 300 miniature 8 ch mixer amp

2 neatly shorted D-S-G mosfets and 2 neatly o/c 0.056 ohm wide SM resistors
leading to each of the o/p filter electrolytics, no overheating, charring or
burning anywhere.
So assuming no leads to speaker or speaker problems what would cause this ?
I had previously desoldered one of the o/p electrolytics on the other more
accessible board to try and read the ident of the obscured mosfets and that
cap presumably only had marginal soldered contact via junk lead-free solder,
could that be a cause? the 2 off per channel 100V, 470uF HF filter caps
across the output.

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