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Author Topic: Help Identifying name of part  (Read 412 times)

Offline blairc2007

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  • Member Since: Apr 2018
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Help Identifying name of part
« on: April 09, 2018, 01:15:45 PM »

I have a Magic Chef  Model: mcwbc77dzc   mini wine cooler that will no longer cool after a power outage.

I have verified the following:

Compressor has 120vac going to it.
Compressor is coming on and outputting correct amps.
Compressor fan is on and running
Cooling fins are free from dust
Temp sensor is working. (measured resistance)
Both upper and lower evap fans are on and running.

The compressor is not shutting off and getting very hot because I believe no Freon is flowing to cool the unit.  When I first plug it in I hear 3 clicks coming from some kind of relay. This is not the compressor start relay but a different one that has 2 wires going to it directly connected to the MAIN PCB.   There is a brass cooling line that is routed through it. It seems to be some kind of pressure valve that must open to allow Freon to flow?

I measured the resistance of this relay and it is showing as kilohms which is why I think it is the problem. The schematic on the back of the fridge just calls this a  "valve."

I have no idea what this is called or where I can find one. Can anyone help me?

Offline scrapiron

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Re: Help Identifying name of part
« Reply #1 on: April 09, 2018, 04:09:50 PM »
It looks like a reversing valve, which is used to reverse the flow of the freon. When the valve activated, the cooling or evaporator coil will change from cold to warm to allow the coil to defrost. It may be stuck in a defrost cycle. When the cooler is running, do you have approximately 120 volts AC at the yellow and blue wires of the valve? Did you try running the cooler with the wires from the valve disconnected and insulated separately with electrical tape? If it cools then, that would indicate a failed control board keeping the valve in the defrost position.
Also, could you post pictures of the model # tag, the Schematic and the tag on the valve?

Offline blairc2007

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  • Member Since: Apr 2018
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Re: Help Identifying name of part
« Reply #2 on: April 09, 2018, 05:14:21 PM »
Thanks for the reply.  So I measured at the 2 yellow and blue wires with the compressor running and I do not have 120vac which I assume is normal?  I would expect that to only get voltage when defrost most is activated.  I disconnected the yellow and blue wires and let cool for 30 mins without any drop in temperature.

I have attached a picture of the schematic/model number, but I do not see any tag on the valve/relay.

I assume all signs would point to a defective Main PCB since it likely is what got damaged during the power surge.  I do not see any physical signs of damage on the board and the 1 fuse that is on it is testing good.

Model # is: mcwbc77dzc

Offline scrapiron

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  • Member Since: Nov 2011
  • Posts: 673
  • Country: us
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Re: Help Identifying name of part
« Reply #3 on: April 10, 2018, 11:22:41 AM »
Here is a link to Magic Chef's parts page.
https://mcappliance.com/find-parts