[RFI] Re: Whirlpool Duet Washing Machine RFI update

Tim Groat tcgroat at earthlink.net
Sat Feb 12 13:34:48 EST 2005


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 at 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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