97 replies to this topic

[RegUS_PatOff]

[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

 

 

[agustind]

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

Attached Files

•  Maytag.jpg   96.16KB   255 downloads

[RegUS_PatOff]

no need to remove 14, 15, 16

 

the ADC is 13

 

 

[agustind]

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.

[RegUS_PatOff]

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.

[tomiii]

[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.

[igor_ch75]

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 : )

[steeler11]

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.

[patricia]

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?

[cwilkins]

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

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

 

[jahjahbinks]

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

[jahjahbinks]

[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?

[cwilkins]

 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.mgchemica...ducts/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-

[tech_head]

Hi,

Looks like I'll be trying som eof the solutions here.
I blamed the kid for leaving the door open. 8-(

Oh well, I'll pick up a cap. I did hear buzzing one night.
I think it was trying to go into the defrost cycle but could not.

I know it's a defrost problem, no air into the refrig but frezzer bone cold and freezes icecream rock hard.

tech

[tech_head]

My spelling was horrible in the last post.
Anyway, I picked up the part from a local distributor.
Fridge is unplugged and defrosting.
I'll pull the cover tonight and install the part.

Even though I'm an engineer, I didn't feel like replacing the relay and cap. I'll repair them on the old board and keep it as a spare. The local price for the ADC board was about $60. More than new cap and relay but less than a repair man.

tech

[agustind]

Hi all,

I posted a message Mon Nov 7th, 2005 12:41.

Sorry for the late update after 4 months. I couldn't start trying it right away, plus, I wanted to observe the results for a while. Yes, I replace the cap, and everything is "cool" now. No more problems so far... only that my vegetables are getting too "crispy".

BTW, I placed a temperature logger inside the fridge and freezer giving me ~5degreesC (~41F) and ~-17degC (~1.4F) average... is this ok?. What should be the regular/normal/popular temperature in both?

Regarding the ADC, thanks RegUS_PatOff for the schematic and guidance (I may try the zeners next time). Thanks to the Samurai for the web site, it's great.

'til next time...

[tech_head]

Your fridge should be below 40F.
Anything above that can lead to bacteria growth. Before defrost mine will swing down from 38F to about 28-30F.

As far as the freezer; how hard do you want your ice cream to be?

tech