It's not certain the board has a "low voltage side". Motor drive circuits
often have the low voltage control power tied to a primary side circuit.
Since the appliance has no accessible conductors (I/O jacks, etc.)
isolation isn't mandatory, and often is excluded to reduce cost.
Just like a transformerless TV set, you should assume all parts on the
board are hazardous until proven otherwise. Any filter parts you use should
be selected with electrical safety in mind; the applied voltage may be 5VDC
above the 120VAC line.
73,
--Tim (KR0U)
"Cortland Richmond" <ka5s@earthlink.net>:
If it were MY washer, I'd probably work on it; I'd probably pull the board
and put my fixes on it, all in the low-voltage side, testing the bare
board out of the washer for emission levels before and after.
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