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lucyluc67

how to install my new adaptive defrost control board

98 posts in this topic

REG For President!  I went to Radio Shack, got that Capacitor (it was a 35v max, but works).  I shorted the two contacts, the heater came right on!  Made a plastic melting smell, but it appears to be working.

Thanks for the help.

Doug

www.rcscoringpro.com

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Need appliance parts? Call 877-803-7957 now!

[user=3641]RegUS_PatOff[/user] 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.

Brilliant! I got some electrolytic capacitors (5 for CA$1) and replace the one on C2 and I put back the ADC in the fridge. Move the freezer control and after a few seconds, forced defrost. I heard the click, then the fridge stopped and started to melt the frost on the coil...
Thank you so much... Now I just need to monitor to see if all is working fine. So far so good! The whole thing at a very reasonable cost!

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here ya go !

 

1996 Maytag ADC Defrost Controller Schematic  ( MS Paint > pdf )

rev. 10/08/05

MAYTAG ADC.pdf

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Very cool, Reg! Did you reverse engineer this yourself to create the schematic?

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[user=1]Samurai Appliance Repair Man[/user] wrote:

Very cool, Reg! Did you reverse engineer this yourself to create the schematic?
yes !

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wow !  this site is great... 

Here's my story...

I had this exact problem (Maytag SxS 2556) about 2 months ago... called in a Maytag repairman to the tune of about $200.  He "knew" my problem before even arriving... asked me to start defrosting my freezer section before he showed up.  Saw that the evaporator coils were almost a block of ice and blocking the inlet from the fridge section (hence no flow, warm fridge, cold freezer).  He replaced the defrost thermostat for $20 and the whole thing worked fine... for about a month... same problem... this time I knew what to do.... thawed out the evaporator coils, and upon inspection I saw that the thermostat was not connected to the evaporator line like it was supposed to be. (being the "genius" that I am I though mearly clipping this back on would solve my problems)... well, a month more later and presto, same problem..:X    ok... I really don't like spending $200 to have something "fixed" and not have the problem solved... this time I was taking on the task (with no knowledge of refridgerators at all)... found some scehmatics on the Maytag website and eliminated the theromostat as the failure point... one google of "Maytag Adaptive Defrost Control", and presto, i'm here!  Great stuff !

Thanks to all here, and a special thank you to Reg, nothing like going from a $200 service call to replacing a $50 part, to fixing the $50 part with a $1.19 capacitor !

Due to lack of decent electronics shops in the area, i've used a 22uF 35V cap from Radio Shack at the C2 position.  Can anyone tell me if this can lead to long term problems.  I'm thinking of getting the proper cap (22uF 50V) and putting that in (sorry Reg, tatalums are about $15/each !! ouch !!), but will this 35V one from RS work in the meanwhile, or maybe it will be fine as it is ??

Thanks again everyone that posted, and what a great site Samurai !  (ps. nice place otterville is.)

cheers, gs

 

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The 35v cap should be OK, it only charges to about 35v with 4ma, and while the relay is on, it's only at 24v.

If the cap can't handle it, it won't ruin the cap, in this case.

The non-tantalums may last another few years.

If you can find a tantalum  22uF @ 35v, that may last forever.

I'll check some sources.

 

 

 

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Boy I'm glad I found this thread. I too have a Maytag MZD2766. I was initially blaming the kids for leaving the door ajar because it was intermittent at first. Then I noticed after a week or so I would have to manually defrost the coils because the ice/frost was preventing airfow into the refrig compartment.

I did the little test of shorting L1 and Test on the ADC and sure thing I got a buzzing sound. After a trip to the parts store and $60 later I installed the new ADC and preformed the L1 - Test short. The compressor turned off and the the heating coil came on. Bingo. Bad ADC. I saved $100 bucks, learned about the defrost cycle, and apologized to the kids.

Thanks a million

Oh if anyone wants a bad ADC let me know and I'll send it to you.

John

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[user=4095]jmizzi[/user] wrote:

Boy I'm glad I found this thread. I too have a Maytag MZD2766. I was initially blaming the kids for leaving the door ajar because it was intermittent at first. Then I noticed after a week or so I would have to manually defrost the coils because the ice/frost was preventing airfow into the refrig compartment.

I did the little test of shorting L1 and Test on the ADC and sure thing I got a buzzing sound. After a trip to the parts store and $60 later I installed the new ADC and preformed the L1 - Test short. The compressor turned off and the the heating coil came on. Bingo. Bad ADC. I saved $100 bucks, learned about the defrost cycle, and apologized to the kids.

Thanks a million

Oh if anyone wants a bad ADC let me know and I'll send it to you.

John

I could use it if nobody else responds...

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hoe do i get to the adaptive control board on a model msd2756aew? may tag refrigerator

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[user=4265]James athey[/user] wrote:

hoe do i get to the adaptive control board on a model msd2756aew? may tag refrigerator

 

see the 3 messages on page 2 starting with the one from RegUS_PatOff on: Sat Sep 24th, 2005 20:12

 

 

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Excellent site. Awesome thread... after reading it, I could see at the end of the tunnel :)

I have a Maytag MSD2756AEW. I read all the discussions about it and the infamous ADC. I read the message about how to get there an short the L1 to TEST. If I had gotten there I would have even gone ahead and replace the also infamous C2 so I can solve this well known problem once and for all.

But... I couldn’t. I almost got a hernia trying to take off the first white plastic cover. It seems designers try really hard to make it difficult for mortals like me… and they are getting very good at it. Besides the tabs holding it, there is like a little nail sticking out as a stop for the cover to come out. I followed RegUS_PatOff’s instructions and “super-bowed” it. Then, I got the screws out, everything seemed ready to come off and finally get to the ADC, but… I believe the big piece of styrofoam (parts 14, 15, 16 in the provided parts diagram-see attached) is what prevents me to take all out to access the ADC. Big frustration.

I know many of you have gotten to get all the way to the ADC; please let me know the trick. Thanks a lot!

Agustin

post-4347-129045087924_thumb.jpg

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no need to remove 14, 15, 16

 

the ADC is 13

 

 

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thanks for the reply.

Refering to the same parts picture, I could see the ADC (part 13) by bending the inner plastic cover (part 1) so I knew it was there... but I couldn't reach it! :headbang:

I thought I need to somehow take part 1 (inner cover) off to reach 13, am I right?. Cover 1 is tightened up with the 14,15,16 and hides the ADC.

Thanks again.

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sorry, it's been awhile since I've took it apart.

loosen the (2) big-flat-head screws, one behind each light socket, then slide cover to the right.

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Reg,

You are the man! I had the same problem for the last two months with my Jenn Air side-by-side bought @2000.  My wife decided to dump it to garbage and replace it with GE. She has already booked one $2800 @home depot. That inspired me to repair it. After reading your instructions and postings, I went to Radio Shack and bought the cap. It worked!!!

Thanks a bunch.

---James

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Thanks for the site and the thread. This is great.

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[user=3641]RegUS_PatOff[/user] 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.

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Thanks a lot for the info on C2! If worked perfectly well - no buzzing anymore; test defrost was perfect; will see how it will work in the next months.

I wanted to share some info to help others finding the capacitor. It is an Electrolytic Axial type. Sunnyvale and Palo Alto Fry's carry 50v and 63v in their stores at $0.99, while Radio Shack has a lower voltage (35v) only. Note that Radio Shack also carries an assortment of capacitors in a single box, which includes 22uF63v, but it's radial and will be less convenient to connect.

At a local Fry's I bought 63v capacitor, which is marked as "NEH22M63CB" - use Google and you will find plenty of online stores, who carry those. If you have Fry's in your area - call them and ask if they have part #1710243 (63v), or #1710195 (50v).

In addition to capacitor, I bought Silicone Conformal Coating by MGChemicals to cover capacitor and board after soldering.

Good hunting : )

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Thanks for this great site and the info. I have the same defrost problem on my Maytag, just replaced C2 per RegUS_PatOff's instruction (thanks to RegUS!) and am waiting to see the result.

RegUS_PatOff, if I understand your schematic correctly, C2 would get the full 120V charge when Q1 is off, meaning the 36V Zener diode is mandatory in this case? Thank you again.

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I have a Maytag Wide by Side model# MZD2766GEW series 10. I ohmed the thermostat and it is opening and closing correctly. I ohmed the defrost heater- tested Ok. I then jumpered the heater and it heated just fine, so I determined that the ADC was defective. I checked all the voltages to the board to make sure it wasn't a connection problem and they were all correct. I shorted L1 and the Test but the unit still doesn't go into defrost. My temp control was closed at the time, which according to the information I read is right. I do not get any buzzing of the relay. I purchased a new ADC at a local dealership, but it looked used and has the same problem my original one does. The dealer refuses to refund or replace the ADC, so I am trying to find a way to repair the PCB. From what I have read, C1 seems to fail.  There is alot of information on replacing the C1, but does anyone have any information about a replacement relay?

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...and Google draws yet another DIY appliance repair victim to your site! :yikes:

But thanks to this thread (and Google), my food is still cold!  Yay!! :D

I've got this Maytag MSD2556AEA, which isn't defrosting. At least not automatically. A few nights ago I took the board out, beat on the relay with a screwedriver handle a few times, put it back in, shorted L1 to Test and successfully initiated a manual defrost cycle.  That brought the freezer from 20F down to 5F over several hours.  The following night I shorted L1 to Test again.  I heard a click, but no defrost cycle.  Just kept right on refrigerating.  Same thing again the next night.  Wasn't easy, but I got my screwdriver handle all the way back there and beat on the relay again.  After hitting it several times (and cussing a lot), it kicked over to defrost mode.

Sounds like the relay contacts, right?  What I'm wondering is, has anyone replaced the relay on this board, perhaps with a heavier one?  I'm ordering a new ADC board, but I'd like to repair this one, since it seems I may go through several of these boards over the (hopefully long) life of this fridge.

BTW - In case anyone's wondering, it seems Maytag is crap anymore.  I've read so many horror stories over the past week. I've had way to many problems with this fridge since we got it, and the notion that this silly board is going to fail every five years, it's all a little rediculous, idnit?  Add to that, a one year warranty on a major appliance that should last at least 20?  What's up with that?

Sorry, I shouldn't be whining.  It could be a lot worse.

Thanks for being here,

                              Charlie

 

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after reading the post i was just wondering if anyone had determined what was causing the problem? i have found in my travels that i also need to replace the heaters and or the termination switch as well ? and these are and or parts that also need replacing. those micro relays just arn`t that great

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[user=5962]patricia[/user] wrote: 

the relay is just another name for contactor theses can be purchased for rat shack but you will need to reseal the board this can be done using what is called plastic dip which is used for dipping tools to recoat the handles

 

I have a Maytag Wide by Side model# MZD2766GEW series 10. I ohmed the thermostat and it is opening and closing correctly. I ohmed the defrost heater- tested Ok. I then jumpered the heater and it heated just fine, so I determined that the ADC was defective. I checked all the voltages to the board to make sure it wasn't a connection problem and they were all correct. I shorted L1 and the Test but the unit still doesn't go into defrost. My temp control was closed at the time, which according to the information I read is right. I do not get any buzzing of the relay. I purchased a new ADC at a local dealership, but it looked used and has the same problem my original one does. The dealer refuses to refund or replace the ADC, so I am trying to find a way to repair the PCB. From what I have read, C1 seems to fail.  There is alot of information on replacing the C1, but does anyone have any information about a replacement relay?

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 Whatever you use to seal the board, you really need to seal the relay (aka contactor) as well.  The problem is moisture, both in the form of simple high humidity, and possible condensation directly on the board.

This moisture could lead to corrosion, electrical current leakage, and accelerated erosion of relay contacts.  Any of those could cause the board to fail (ahead of schedule, I mean), or worse.

So both sides should be dipped/sprayed/whatever thoroughly to ensure a complete "hermetic" seal of the board and all components, especially the relay.

Here's one option (brush-on application, acrylic lacquer based): http://www.mgchemicals.com/products/419b.html ...or you can google for "conformal coating."

Now I suspect it's quite likely that you could neglect to seal the board/relay and suffer no ill effects at all, but I don't like taking my fridge apart and installing $50 parts any more than necessary, so I'm not taking any chances.

My $0.02...  Apologies in advance to those who think all this is obvious. :)

-cw-

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