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Freezer not defrosting, heater and terminator have continuity

19 posts in this topic

My old Amana BB120TE bottom freezer isn't defrosting.   After following all the steps in the incredibly helpful videos on this topic, the heater element and defrost terminator both appear to be OK, with continuity.   The freezup in my freezer was slightly different than the one in the videos in that there was rime ice all over the fins and coils, but there was also clear hard ice up around the defrost terminator and the wire connectors.     

 

Questions:

-  does this indicate that the Adaptive Defrost Control  (ADC) is bad, or is there something else I can check?    I'm asking if there is something else to check because the ADC for this fridge is no longer available.  (part 12050505).     

-  can anyone please tell me how to access the ADC which, according to the parts diagrams,  is located in a box under the front of the fridge with the high voltage circuits?

 

 

Looking forward to your replies.

 

Thanks in advance

 

 

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...  there was rime ice all over the fins and coils, but there was also clear hard ice up around the defrost terminator

 

post pictures ?

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Do 2 things.

1.Initiate defrost and check amp draw.

2. Check all door seals for a good fit.

Loose door seals can allow humid ambient air to enter the box and cause excessive moisture on the coils,resulting in more ice.

The heater and defrost stat can read continuity and still be bad.

The defrost thermostat could be opening too soon and terminating defrost.

Make sure the defrost thermostat is mounted correctly and in the correct location.

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RegUS_PatOff  I should have taken picturesprior to manually defrosting,, but didn't.    Definitely will next time. jumptrout        Thanks for the very helpful suggestions.  Please understand that I'm not a trained repairman, so some of my questions will be novice level.    I tried to initiate the defrost cycle by dpressing the light switch 4 times within 8 seconds.  I did not notice any change in what the fridge was doing, meaning no change in sound or anything.   The evaporator fan above the coils seems to run continuously.    Does that provide any helpful info?     I'm ignorant as to where and how to check amp draw, but am willing to try any recommendations. I will check the door seals for leaks.   Honestly, I don't know the precise location where the defrost thermostat should be positioned, and do not have a repair manual for guidance.  I can tell you it is currently positioned on the top of the evaporator coil at the top near all of the wires.  It is on bare aluminum, not touching any balck coating on the tubing.  Are you aware of a way I could find out if that is the correct location? I can replace the heater and defrost stat easily enough, should I just go ahaead and replace them?  

 

Many thanks for your help.

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We must have a model number for further assistance.

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The refrigerator model is Amana BB120TE, as stated in the 1st line of my post.   If there is any additional info I can provide please let me know.

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Yes it is. I am blind in one eye and tend to read every other word.

Your problem is going to be a bad ADC or a bad defrost termination thermostat.

If your ADC will not enter the defrost mode by your initiation,it may be the only problem.

A defrost thermostat opening too soon can also cancel the defrost mode.Since you can not initiate defrost,I would replace the ADC.

 

http://www.repairclinic.com/PartDetail/Defrost-Control-Board/12050505/401456?modelNumber=BBI20TE

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I must agree with my esteemed colleague.  A Samurai-approved technique for troubleshooting refrigerator defrost problems in units using ADC control boards is to verify that everything else is within spec (defrost heater, defrost limiter or terminator, wiring, etc.)  That which is left must be the problem: the ADC board.  

 

Failure to initiate defrost, either manually as in this case or automatically as in the famous Jazz control board failure, definitively implicates the ADC control board as the faulty part ==> http://www.repairclinic.com/Amana-Refrigerator-Model-BBI20TE-ID-511653-Circuit-Board-Timer-Parts

 

Defrost-Control-Board-12050505-00646503.

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Ugh,  I was afraid you guys were going to say replace the ADC.  Problem is... it is no longer available.

So, what do you do when you can't get that type of part?  Buy a new fridge, or try to get the ADC repaired?

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... dpressing the light switch 4 times within 8 seconds. 

 

... either the freezer or refrigerator door light switch 4 times in a 8 second period.

Allow at least 1/2 second between each switch condition.

 

There's an ADC oneBay for $ 200 :woot:

Another one sold for $ 110 :woot: 

 

It may be possible to wire-in a mechanical Defrost Timer .

BBI20TE tech sheets and service manual:

http://appliantology.org/files/file/454-amana-fridge-bm/

(those Evaporator frost pictures may be helpful)..

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Sensei,

Thanks for your suggestions.  I'll try the manual defrost test on both switches.

 

I saw the ADC on ebay and was concerned that it is a used part.   Do pros go the used parts route or try to get the original part repaired? 

 

Lastly, the ADC appears to be located in the high voltage box, under the freezer, behind the toe grill.   (see link below)

http://www.youserguide.com/wiki/Whirlpool_BBI20TW_P1199101W_W_parts-018

 

Am I reading it correctly or is the ADC someplace else?

 

Can you tell me how to access that high voltage box the easiest way?  It's gonna be a bear if I have to lay that fridge on it's back to get the ADC out.  

 

Thanks in advance

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RoughShod,

 Yes sir, I looked at the manual Reg posted.  I got 6 pages in the download, so I don't have page 24.  

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... looked at the manual Reg posted.  I got 6 pages in the download, so I don't have page 24.  

you got 6 pages in the tech sheet T120_0R0.pdf

there's 53 pages in the service manual S120_0R0.pdf

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Reg and Kdog,

 

Ah Ha!!    My bad.    I forgot that I was unable to download S120_0R0.pdf  earlier because I have exceeded my daily allocation.

 

I will try again tomorrow.

 

Thanks very much.

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NOTE: The compressor MUST be running when the forced defrost is initiated.

If the compressor is NOT running the defrost will not start ...

Edited by RegUS_PatOff

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Update: I attempted to initiate the defrost cycle a few more times per the instructions with no success.    So, with the help of the service manual the ADC has been removed.  That part is no longer available so it's on it's way to a circuit board brain surgeon.   I can only pray it works when I get it back.

 

There was some interest expressed in seeing photos of the situation, and maybe they can be useful to someone else,  so some new pics are attached.    This amount of frost has built up since Sunday night, about 72 hours ago.    If you have any comments I'd be interested in hearing them.

 

I cleared some of the frost from around the defrost thermostat.  Can someone please tell me if it is positioned correctly?

 

Thanks for all of the help you guys on the forum provided over the past few days.  

post-80518-0-22465100-1355350249_thumb.j

post-80518-0-80792600-1355350256_thumb.j

post-80518-0-61662000-1355350264_thumb.j

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looks like the Defrost Thermostat is positioned OK

(hard to tell with the excessive frost)

May need to manually Defrost the Evaporator with a hair-dryer,

then post some pictures after a few hours of Compressor run time.

 

If you were to jumper L1 to D on the ADC for a few minutes,

you should see the Defrost Heater working

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If you were to jumper L1 to D on the ADC for a few minutes,

you should see the Defrost Heater working

 

And if this works, then I think Brother jumptrout may have called the dance on this one early on...

 

 

The defrost thermostat could be opening too soon and terminating defrost.

 

I have seen this before and it can be a real hair-puller.  And Amana is famous for having flakey defrost thermostats.  At any rate, it's a whole lot less expensive (and a whole lot more available) than the ADC board and worth a try ==> http://www.repairclinic.com/PartDetail/Defrost-Thermostat/10442409/379484?modelNumber=BBI20TE

 

Defrost-Thermostat-10442409-00714392.jpg

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