These class D amp modules are not unipolar.
On 60% mains it has + and - 38V smps rail supplies.
I replaced each of the 470uF,50V with 2 seriesed 1000uF,25V, so much bigger
volume than the tiny 15mm long, 12mm diameter originals, skewed off the
board , but room inside the case and the blown Rs. But it is now working
with a pair of mica backed IRF740 instead of the fairly expensive proper
mosfets that seem to have only one supplier in the UK. With no undue heating
at low power, bit higher RDSon etc.
Very strange having a whole amplifier weighing only 60 gm but the advantage
is they easily unplug and can easily power up off a bench supply. So using
+&-30V I noted what the standing DCs are around the mosfets, no sign of any
oscillation, I assume the oscillator is taken from the SMPS oscillator to
avoid beats problems if free ruinning. Will have to remount in case for
proper airflow before full power testing, whatever that is, 35W, 100W or
150W each channel.

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Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
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