View single post by tomiii
 Posted: Mon Dec 26th, 2005 06:42 am
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tomiii

 

Joined: Sun Dec 25th, 2005
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RegUS_PatOff wrote:
I have a Maytag MSD2756AEW and had the same defrost problem.

I drew a schematic of the ADC and found the cause and fix for the "buzzing relay"

It's a bad electrolytic capacitor, C2, 22uF@50v

Try jumpering in a good one across it. (there is a protective coating over the entire board)

Watch the polarity and also be careful, the minus (-) side of the cap is connected to L1 120v HOT side of the power line.

I drew the schematic with MS Paint, and will soon draw it with a schematic program and upload it here.



also, neither the compressor nor the defrost heater will work when the temp control is turned down (but the relay will still energize) try it at max cooling setting.



Wow, what an excellent source of information! :-)

My refrigerator: MSD2756AEW

Can a bad C2 cause any other failure modes besides a buzzing relay? Shorting L1 & TEST on my ADC causes the relay to click but no buzzing. The heater coil doesn't get hot. I don't believe the compressor turns off either. Perhaps this is just a momentary click (now I feel like an idiot for putting the whole thing back together again without verifying that). Shorting L1 & TEST again does not produce another click, so I assume the relay is still energized, unless the PIC somehow enforces a minimum time between cycles.

The thermostat works fine (i.e. closes when cold) and the coil gets red hot when I apply 120V directly. I've been defrosting manually every weekend for several weeks, but I'm leaving town tomorrow for almost a month and hope not to come home to a puddle of water on the floor. :-(

FWIW, last time I went on vacation I came home to find the control board behind the front panel controls had a shorted triac, which energized the solenoids in both the ice maker & dispenser door long enough to melt the plastic beyond repair (had to replace it) and eventually burned out a trace on the board. I fixed the board with a $1.99 triac and some wire. Now 6 months later my ADC is bad? I bought Maytag because Consumer Reports told me it was reliable. Puke.