Author Topic: Replacing both evaporator fan motor and motherboard on GE SXS Refrigerators  (Read 7987 times)

Offline rickgburton

  • Technician
  • Member Since: Oct 2007
  • Posts: 212
  • Country: us
  • Ricks Appliance Repair - 30 Years Experience
    • Buy me a beer through paypal
Thanks, and since I'm still in the refrigerator forum, here's a couple more I made on using the touch method to diagnose sealed system issues. This is old school but it worked great for me and doesn't take very long to become quite accurate using it.

OWNER/SERV TECH: RICK'S APPLIANCE REPAIR
APPLIANCE SERVICE TECHNICIAN FOR 25 YEARS
ONLINE SERV TECH: ApplianceBlog.com ApplianceJunk.com
CERTIFIED TYPE 1; TYPE 2.....REFRIGERATION SERV

Online AJ

  • Technician
    Administrator
  • Member Since: Jun 2007
  • Posts: 8912
  • Country: us
    • Buy me a beer through paypal
    • ApplianceJunk.com - Appliance Repair Help
Nice, you need to start writing a book for us.  O0

Offline ZZZ

  • VIP Member
  • Member Since: Dec 2008
  • Posts: 11

Offline archibald tuttle

  • VIP Member
  • Member Since: Jul 2013
  • Posts: 22
Rick and company,

I too wish to thank you for the diagram which ought to be pasted to the back of every one of these fridges.

Two questions on these GE SxS.  How can you tell if you have the new board.  assume the relay might be obvious or . . .  date code or?

I've been through two boards in two years on one of these SxS and now its down again.  seems like defrost symptoms but could be evap fan, i.e. freezer is refrigerator, refrigerator is oven . . .

fixyourboard.com has a pretty good logic schematic for the defrost circuit
http://www.fixyourboard.com/techzone/refrigerators/ge_fridge_nodefrost/defrostflow.html
but calls for ohming the "bimetal switch".  i don't thing these have bimetal switches. I thought they have thermistors which vary resistance with temperature.  maybe they are still bimetal, and maybe the reading they are looking for - under 10 ohms - indicates a range, e.g. 0 to 10 that is within appropriate operating characteristics.

first problem is, identifying the "bimetal switch" which I assume from your diagram is the evaporator thermistor which is also used to terminate the defrost cycle. (I'm a little hazy on that terminology relative to good old analog defrost operation because the defrost cycle was operated by a timer and the bimetal switch turned the element on and off to prevent overheating during that timed cycle but did not terminate the cycle.)  Assuming I have the right thing to test you show ohming J1 pin 5 to J1 pin 4 and then I'd refer to the thermistor values to see if the ohms vaguely correspond to current evap temp.  One thing not mentioned, is such a test reliable if the junction is still plugged in? if so, maybe this is a slight advantage to the PC board control as in most analog versions you had to unplug everything and test it on its own - although that also highly logically confirmed what was working and what wasn't.  no black box to deal with.

And , I'm still black box as to whether the new and disimproved model responds to the thermister by reentering refrigeration mode or it simply turns off heater and the processor is running a timer (and if all this utter nonsense overcomplicating fridges in order to cost people money and grief is actually aimed at some miniscule energy savings and I can blame this whole disaster on EPA -  who are pretty much singlehandedly responsible for most problems I encounter in life - you'd think they would have a relative humidity sensor as well to change the cycle timing rather than a knife edge algorithm of how fast the evap warms but maybe that is a reasonable surrogate for it being iced out and I'm only complicating what is already too complicated, but I digress).

As to the evap fan, I'm not clear what the real benefits are of two or three speed operation.  you list 12V high 8 V for low although then I see a listing of 4V low, 8V med, 12V high. I've generally found good ole fashioned AC evap fans to be virtually bomb proof.  I'll come across them completely iced up or gummed up with locked rotor.  clean em up, little lube on the shaft and back in business.  water don't hurt 'em, ice don't hurt 'em, food gunk don't hurt 'em.

If I read your first diagram right, after observing resistor condition and checking for open or short condition J2 pin 3 to J2 pin 8 and then following up at motor if either is observed, I would test for voltage between J2 pin 3 and J2 pin 4 during operation.  And if I'm not getting voltage at all to J2 pin 8 this is an indication of damage to the board possibly resulting from some misoperation or misapprehension of the evap fan.  Now, you say this should be less likely with new boards because of relay style operation, although I'm wondering if these guys every heard of a fuse.  We used to used those to protect DC control circuits as well as mains, just sayin . . . 

I guess in the bigger picture while I'm thanking you for your extensive work to help crack the black box a little bit -  what is the point.  I've got plenty of work without these headaches.  I suppose if we are trying to cure unemployment by turning 30 million more people into appliance repairmen it would be more efficient to keep writing unemployment checks and not have all our food spoil - maybe that explains the increase in food stamps.

Maybe I can ask if there is another thread to discuss what manufacturers have actually got this figured out best and will move the the bottom of this post there, but can't avoid asking when I'm on the 3rd go round in 3 years for this fridge whether there are better options. Can I still buy an analog controlled fridge or one with minimal printed circuit work, or small circuits devoted just to the icemaker for instance which have been prevalent for years but if the icemaker goes, you don't lose all you food.

I will certainly plead guilty to not having cracked the depths of the problems the way that rick has and maybe once you really understand a board, the GE isn't any worse than anybody else's - or perish the thought, maybe it is better.  (although fixyourboard.com also identifies their 13.5 volt power supply as fluky.
  http://www.fixyourboard.com/techzone/refrigerators/ge_fridge_testload/ge_fridge_testload.html.
don't know if they fixed that on the 'new' versions.)

and fixyourboard warranties their repairs for 2 years which is nice but to me the gold standard is 22 years not 2 years.  I've got an analog SxS Estate brand (think I once figured out it is a whirlpool but not sure) fridge I bought from Sam's club 22 years ago for 500 bucks and done nothing but clean the condenser grid a couple times prophylactically.

if there is a modern manufacturer who can take those guts and wrap some stainless steel around 'em and sell 'em for a grand they'd be in the money from my perspective.  I'd tell everybody I know to buy one.

And I'm now faced with the decision whether to fix this GE again (maybe better than I did before by buying a new board without really knowing why the old one failed, maybe Rick's work will help me to know why it failed) or to throw in the towel and choose another manufacturer or different GE control strategy because counter-depth would be better in this setting anyway. If so, what manufacturer should I choose?

if you made it to the end of this post you were able to suspend the ADD that has you being an independent entrepeneurial serivce person (e.g., for extreme example see my screen name) long enough in favor of ARD - (i.e the retentive disorder) when it comes to appliance repair. thanx for playing. thanks for any service ideas and any observations on brands which seem to have more analog or better worked out or separated digital control regimens.

brian

aka- the man who refuses to buy a washing machine with a digital main controller.




Offline ZZZ

  • VIP Member
  • Member Since: Dec 2008
  • Posts: 11
Rick and company,

I too wish to thank you for the diagram which ought to be pasted to the back of every one of these fridges.

Two questions on these GE SxS.  How can you tell if you have the new board.  assume the relay might be obvious or . . .  date code or? .....

/quote]
The bimetal is made by TOD and is an L140-30, if memory serves me right.  This means it will open at 140 deg. F. and close at 30 deg. F.  To test one, cut the leads and remove.  Cut the leads about an inch from the bimetal because you will have to reinstall it with very little extra wire slack).  A new one comes with long leads.  The connectors must be sealed with RTV silicone I to keep moisture out of connector. Heat shrink or tape will not be sufficient.

 Tape the thermocouple from your temperature meter to the side and clip your ohmmeter to the leads.  Put some water in a pan on the stove and heat to 160 degrees. Place in water, the device should open when the meter indicates 140 + or - 5.  Then move it to a working freezer, it should close at 30 + or - 5.  Do this four or five times to be sure. It will not have a variable resistance, it will be zero or infinity. Or, you can just buy a new one for $9.00.   Here is a link to TOD, they make most of the bimetals out there:
http://www.thermodisc.com/en-US/Products/Bimetal/Pages/39T.aspx
You did not state how your boards are failing, that would be the best indicator of what is going on.  Do you have a surge protector on your electric service or refrigerator outlet.  I would invest in a good one for the panel as voltage spikes (dute to lightning and utility switching) are the number one killer of boards in A/C, furnaces, washers, audio and video equipment, and refrigerators.  The newer style board has the two resistors in Rick's photo in a different location from the older boards.  There is no date codes on most boards. 
« Last Edit: July 11, 2013, 10:11:19 AM by ZZZ »

Offline archibald tuttle

  • VIP Member
  • Member Since: Jul 2013
  • Posts: 22
OK, so the thermistor that rick's diagram says terminates defrost is not the same control as the bimetal?  I may have missed it in the diagram but I don't see other leads coming back from this bimetal sensor to the board.  or is it just in series with the Def terminal on the AC side rather than the DC control circuit.

and thanks for tip to look at location of resistors to identify different board.

there was definitely something cooked on the original board when I changed it and I left it sitting on my bench for 2 years in the box from the replacement board but can i find it today . . . nooooooo.

I didn't do the second replacement.

I think this thread was just starting up back then when I did the first and wish I had found it then because I would have had a better chance of tracing the cause.

Yes I understand power spikes are a problem generally although not really a believer that current surge technology can quench lightening level problems without damage to sensitive electronics although I think instability and switching on the grid can be controlled for. 

But no other damage to electronics in this building and it returns me to my concern about having this stuff digitally controlled to begin with.

thanks, headed over there to have a look right now. Might have a little more info next time I post.


Offline Spannerwrench

  • Technician
  • Member Since: May 2012
  • Posts: 59
The evaporator thermistor controls when the unit comes out of defrost, unlock most refrigerators it is not controlled by the TOD, the TOD is used only as liner protection.  If the thermistor fails that's a safety device.

Offline ZZZ

  • VIP Member
  • Member Since: Dec 2008
  • Posts: 11
The TOD is a line voltage device used as an over-temperature limit.  It is wired in series with the defrost heater.  The door openings, evaporator thermisters, compressor run-time, are all inputs to the adaptive defrost system which initiates and terminates the defrost cycle. The TOD is a safety to keep from having the heater run wild if something fails in the control circuit, nothing more.
I retired as Electrical Foreman at a University with over thirty million dollars of equipment in the Public Television and Public Radio studios and another twenty million dollars worth of stand alone electronic equipment.  I can assure you that surge suppression works very well.  Obviously, the better it is the more expensive it is. But even the cheap ones are a thousand times better than nothing at all.
Sq-D and GE and other panel manufacturers make residential surge suppressors for their breaker panels.  They cost under $200 installed, and come with a $50,000 warranty.  As an electrical contractor in an area with a lot of lightning, I sell a  lot of them.  We tell the customers to contact us if they have any failures during a thunder storm or power outage and we will file the claim.  In 9 years we have yet to have a complaint.  They work.
 

Offline ZZZ

  • VIP Member
  • Member Since: Dec 2008
  • Posts: 11
Sorry, I got side tracked on my last post.  I forgot to ask:  On the two previoius board replacements was it due to a problem with the evap not defrosting, did you replace the board only (no other parts), and did it fix the problem?

Offline archibald tuttle

  • VIP Member
  • Member Since: Jul 2013
  • Posts: 22
yes, first time it was defrost problem.  remember that there was some obvious damage to the board and I saved the board but as I said, no can find.

I'm wondering where to look for the onboard wiring diagram on these GE SxS units. I haven't been able to find one, which would have answered my question about the bimetal.

so this is definitely a defrost episode we're having here and not evap fan problem .  just saw the fridge.  aside from the obvious ice build up in the back of the freeze, getting 13.5 volts J2 pins 3-8 and 12.5 volts J2 pins 3 -4.

I moved the remaining food to another fridge and I'm letting it defrost tonite so I can get at the evaporater, but I'm a little confused as to which two legs I should be ohming at the board to test the defrost circuit itself because the connector that supplies the defrosters and compressor alternatively has a line input and the neutral appears to go to the next connector over. so I don't see any neutral wire to the defrost cycle to ohm against the line out from the 3 pin connector.

board looks fine.  no obvious damage or discoloration. maybe it's not the board this time.

but I'm getting infinite ohms across J1 4 to5  which is the evaporater thermister, as well ass across 5 to all the other thermisters which is what is shown in Rick's diagram.  I'm wondering if my J1 could be wired differently. and that gets me back to looking for a wiring schematic with color codes.  I definitely have the WRX5510942 board that's being dealt with here but can't find a serial number on the fridge.  I think it may have been one of those 'refurbs' so unless there is an onboard schematic I'm going to have to find likely model numbers and search for a diagram until I find the one that works.

thanks for playing along, more bulletins as events warrant.

brian

Offline ZZZ

  • VIP Member
  • Member Since: Dec 2008
  • Posts: 11
The resistance will vary inversely with the temperature.  At 68 deg F. you will have 6200 ohms; at 32 deg F you will have 16,300 ohms. Of course the plug must be disconnected from the board.   Not all meters will read this correctly.  Buy some similar resistors at Radio Shack and check your meter.  The serial should on the foil nameplate in the upper right side of the refrigerator section. Save this pdf before it's gone:  http://www.applianceaid.com/pictools/gefridge1.pdf

Offline archibald tuttle

  • VIP Member
  • Member Since: Jul 2013
  • Posts: 22
OK been in the cabinet today and this has an aftermarket L45-15 bimetal that sits at the very top of the evaporator.  seems a little on the cold side. but even the originals are usually labeled so don't figure the guy who was in here last year would have gone too far awol but does anyone know the normal design temps.

anyway, this one ain't easy to trigger so it ain't easy to reclose the switch by dipping in ice water at a 15 setting.  I put it all back together and run for a couple hours and it still hasn't closed assuming I'm ohming the right wires.  i'm pulling the plugs on the 120 end of the board and testing the orange wire that Rick has labeled neutral on the exteme left hand end of the bigger connector to the blue wire at the center of the 3 pin comp/defrost plug.  these wire color codes check out inside the box.

if it isn't reset by tomorrow I'll cut it out and join the wires to make sure I'm testing the right ones and then get another.  and i'll get on to seeing if the adaptive defrost seems to be working.

I don't find any way to trigger the card via the controls (no digital controls or address to the card on this one, only a typical temperature dial).

I suppose from reading the description I could open and close the door a bunch of times but I'm not clear that even a lot of that would trigger the defrost without time.

This was some kind of leftover or warranty return fridge because the serial/model number sticker was removed.  I can see the glue mark where it was upper right side of the fridge box.

I don't find anything on the back that indicates a model number and haven't located a wiring diagram.  don't know where you look on these.  I tried looking for an envelope behind the front and back bottom covers, or one glued onto the back cover but no dice.

I did pull the J1 connector when I was getting infinite ohms across the evap thermister but I maybe should have jumped a range or two on the meter.

It was room temp in the box at that time and I think I was on the 2K range and that should have read around 6400 or less according to the stock figures, but maybe it still shows infinite if the ohms are higher than the range.  may be my bad on that one.  I'll recheck next visit.

They already got another fridge going and I'm just taking this slow and a step at a time.  it's right near other jobs and I want to go step by step and help them decide whether to keep fixing this or switch.  There is counterdepth frigidaire SxS I can bring in but wonder if that is a good choice or frying pan into fire.

or if not frigidaire whose are most bombproof, easy to diagnose, more modularly replaceable control strategy or . . .

brian






Offline clman

  • Technician
  • Member Since: May 2012
  • Posts: 68
  • Country: us
  • 25 Years Appliance and Air Conditioning experience
    • Buy me a beer through paypal
Seen the exact same issue with LG french door models. They issued service bulletins on it and upgraded fan motors.

 

Evaporator Fan blade draging on motor mount EV201NXMQ05

Started by Earl Dryer

Replies: 4
Views: 1500
Last post January 04, 2009, 05:42:09 PM
by shieldcracker
WR60X10074 GE Refrigerator Evaporator Fan Motor

Started by AJ

Replies: 0
Views: 2801
Last post April 02, 2009, 09:34:58 PM
by AJ
5304445861 Frigidaire Refrigerator Evaporator Fan Motor

Started by AJ

Replies: 0
Views: 2799
Last post October 03, 2009, 12:51:14 PM
by AJ
Evaporator Fan Motor Model#LRSC26922TT

Started by resapp

Replies: 9
Views: 1480
Last post August 24, 2012, 03:37:07 PM
by resapp
GE Profile Evap Fan Motor? Motherboard? PSF26NGWA

Started by Stang5Liter

Replies: 5
Views: 1070
Last post January 21, 2013, 01:49:21 PM
by Stang5Liter
GE SBS - Evaporator Fan Motor Keeps Slowing Down

Started by resapp

Replies: 5
Views: 636
Last post February 08, 2013, 07:59:02 PM
by niobrara