Question about Fedders A7DH45B2A Dehumidifier

1 Answer

Fedders Dehumidifier - Wont Turn On

This Dehumidifier won't turn on. The lights on the control panel will not come on at all. I have traced the power to the circuit board in the unit and it is fine. I do not have a parts or trouble shooting manual. Looking for links to manuals and information on how to troubleshoot.

Posted by ExTex on

  • 4 more comments 
  • ExTex Aug 22, 2007


    It is a Fedders A7DH45B2A*A-R. I believe it is the same as a Maytag with the same part number but it starts with an "M", not an "A".

    There are no burn marks on the board anywhere.

    I have found parts lists for both the Fedders and Maytag at Appliance Factory Parts - but no parts manual. There is a Maytag wiring diagram.

    I can check the motor, but I don't know how to check the capacitor. If you will, please tell me how to check the capacitor.

    If the motor and capacitor check out I will need to know how to check out the boards. There is the switch/display board and a second one that that APF call the power board.

    Also, if you know where any parts manuals are I would like to see one of them.

  • ExTex Aug 25, 2007


    There is no damage or oil leaking from the capacitor. I have a cheap digital meeter. I have to put it on 2000K to get any reading. When I do it starts counting up. When I reverse leads it starts anywhere from -200 to -400K and starts counting up again. Will go up till it exceeds the meter reading. Good or Bad?

    Even with a bad capacitor how would this stop the control board from at least lighting up? If the control board is working correctly, will it give error codes on the display?


  • ExTex Aug 25, 2007


    Unfortunately my meter is digital, does not have a dial, so it does not change from "1". I have a very old (1950) analog but I don't know if I can get it to work. Will try.

    As to power, I have traced the power up to the power board, off it to a transformer, then back to the board. That is all good. I have tried to trace the power off the power board to the display/controller board, but don't know what to look for. There is voltage making it to the controller board. Between 2 pins it reads 6.5AC Same 2 pins about 3 DC, 2 other pins 1.5 DC.

    I did accidentally short 2 pins with my probe and the fan motor kicked on. Did not wait to see if the compressor would work or not.


  • ExTex Aug 25, 2007


    There is a connector on the power board that feeds the transformer. That is where the 110 V is at. The output of the transformer is listed on it and I verified it is correct and getting back to the board.

    As to shorting, yeah... The connector contacts are close together...

    No display on the control board but I do have power going to it. If it is still AC, it only 6.5V, not the 10.5 out of the transformer.

    I have checked all of the switches on the Control board. 5 switches, 4 contacts per switch. I verified open/continuity for all switches.

    I need to dig into it a little more to find all the fail safe switches. I was thinking there might be one for low "freon" pressure. But I would think that the board would still light up.


  • ExTex Sep 19, 2007


    Hope you are still with me - been chasing other problems like a pool filter and rebuilding a trailer...

    Got back to the Dehumidifier. As we left it, all of the inputs (Humidity, temp, low level, etc...) are good. The switches all work correctly.

    Issues is still - which board is bad? Control panel or power?

    It started working again for short periods. Got to thinking and realized it has cooled off so might be temperature related. I bought a can of the -65 coolant spray and one time I got it to start again when spraying the Control panel - could not get it to do it twice.

    So, any suggestions on how to tell which board it is for sure? Or just replace one and cross my fingers?


  • sheryljahnel May 16, 2008

    I need help! I'm having the same problem. We have checked to be sure that the unit is completely plugged in and set up properly. We have no power to the unit. For just a flash of a second after several tries of plugging in and unplugging, putting the water container in and out, and put in the filter and taking it out, the light came on and nothing since. The light came on just for a flash while putting the filter back in. Does anyone have any ideas why there is no power to the unit?



1 Answer

Franklin Ouchida

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  • 725 Answers

Looks like a control board, Check the board for burn marks. What model do you have? Some parts are available on-line at appliance factory parts.. also check your Capacitor and fan motor before you install your new Board..Let me know if this helps? Krazytech

Posted on Aug 15, 2007

  • 4 more comments 
  • Franklin Ouchida
    Franklin Ouchida Aug 23, 2007

    To Check a Capacitor
    First check to see if the capacitor is bulging or changed in physical shape of any kind this is signs of a bad capacitor also check for oil may be leaking from it.

    With the capacitor unpluged use an Ohm meter you can check the terminals and the needle will jump upward and instantly fall back to zero. Reverse the leads of the meter and check it again. You will notice the same jump of the meter, and again fall back to zero. This will likely mean the capacitor is good. This check is for a shorted capacitor only, not a measurement of its capacitance, but will let you know if you have a bad capacitor. let me know..

  • Franklin Ouchida
    Franklin Ouchida Aug 25, 2007

    set your meter on the OHMs scale, Rx1 a bad capacitor or motor will burn up the board. so far it sounds like a bad board (most likely a relay on the board}

    bad capacitor*CDBrSdltq8wH5p9lQeRptXKuAS4Iy7TShHYB6k5q*EjmU2GiEl27QUtuVN8h4ILuerOjYYAm5uOWwwAfCUI7rnltGg900q03NdVqSdiwd6YTuKky7oQWkwo/P?dc=4675426666233285937

    Good Capacitor

  • Franklin Ouchida
    Franklin Ouchida Aug 25, 2007

    Hi you are getting 110-120 Volts to the board before the transformer? that is good that your fan motor is good... be careful on what lines you short.
    Have you checked the power button for continuity?

    you still have no display and no power up lights of anykind correct?

  • Franklin Ouchida
    Franklin Ouchida Aug 25, 2007

    I ws also think there is an auto shut off for tipping and also for the pan you may want to check them for continuity or jump them to see if you can get anything... let me know what you get?

  • Franklin Ouchida
    Franklin Ouchida Aug 25, 2007

    did you check the on switch will close when you push it.. also check the pan and tip switch or jump them to see if you can get anything.. yes the board should light up even before the compressor starts.. good luck and let me know...

  • Franklin Ouchida
    Franklin Ouchida Sep 22, 2007

    the main control board just under the buttons.. it is you problem.. let me know what you find out? krazytech



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