Author Topic: No power to ALL Evaporator Fans  (Read 1738 times)

Offline ifixit

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No power to ALL Evaporator Fans
« on: December 04, 2012, 10:52:12 PM »
This is one that was made by Samsung.

Back panel air ducts had ice build up. Large piece of ice on upper right above coils where refrigerant tubes enter(not sure if that is relevant). Pulled off panel and thawed everything out. Evaporator Fan runs fine when 12VDC applied, but not when it is plugged in. I read that when the condensor is running the evaporator fans should be running, is this correct? When the condensor is running there is no voltage to the refrigerator evaporator fan connector.

Both freezer Evaporator fans also is not running. No output voltage at either connector. Fans work fine when 12VDC applied separately. Condensor fan works though. 12VDC output from power supply is OK.

Everything gets cold. Everything else seems to work fine.


Does anyone have access to the service manual RF267A RF26XA SERVICE MANUAL.pdf if so could you please upload it somewhere and send me a link. Don't know if it would help, but would like to check it out.


Or is there any diagnostic between pins on the CN75 connector on the motherboard to check if it is a motherboard problem or a problem in the wiring in between it and the fans.? Is there anything on the board that can be fixed?


Is it a bad main control board or something else?

Thanks for the help, I appreciate it.

Offline AJ

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Re: No power to ALL Evaporator Fans
« Reply #1 on: December 04, 2012, 10:56:44 PM »
I edited your post to remove your link.

Service manual sent via PM.

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Offline ifixit

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Re: No power to ALL Evaporator Fans
« Reply #2 on: December 05, 2012, 04:49:29 PM »
Thanks for the manual and info, it really helps.

The fridge is a GE GFSS6KKXASS made by Samsung which I read is a RF26X

The evaporator fans each run to a transistor TIP42c. I pulled the C-Fan and FZ-Fan ones and they they both test the same, i.e. good.  I swapped them and condenser fan still works but not the other 3 evaporator fans. The schematic then shows they run to and quad op amp LM324.

What is the likelihood that the 3 of the 4 amps in the IC have gone bad? I would rather just replace one IC rather then the whole board if this is a possibility. Anyone know how I would go about testing a quad op amp to see if that is the culprit?

After the LM324 they then go to the main IC, S3P848A, which seems to be the GE programmed brains of the operation. So if I could figure if it is the op amp then I could try that and not have to get a new mobo.


Also, I looked at a service manual for a GE Profile French door fridge that was also made by Samsung, I am assuming, perhaps incorrectly that these diagnotics and flashing faults codes would mean the same thing on mine.
    Mine does not have any start up faults show. When I ran the self diagnostics it did not give any faults. The load conditions show faults that seem to be unrelated to the evaporator fans or inaccurate based on what is accutally occuring, e.g. flashs fault for compressor but compressor runs fine. I do get R-1b which is Refrigerator Fan low, not sure if this means low speed as there is also a Refrigerator Fan High. But I don't get any freezer fan errors.
 
Again thanks for the help.
« Last Edit: December 05, 2012, 04:50:09 PM by ifixit »

Offline jimbo6679

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Re: No power to ALL Evaporator Fans
« Reply #3 on: December 05, 2012, 09:54:56 PM »
Just for reference,so you order the right parts....the fan located in the freezer compartment....blowing across the evaporator coil...is the EVAPORATOR fan.    The fan down under, near the compressor and blowing on the condensor coil, is the CONDENSOR fan.   

I will let the pro service techs explain exactly when each should be running.         Again, for reference, the EVAPORATOR fan is high on the list of most common repair parts for almost any fridge   

Offline ifixit

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Re: No power to ALL Evaporator Fans
« Reply #4 on: December 06, 2012, 07:32:14 AM »
Thanks, I am aware of which fan is which.

I find it hard to believe that all three evaporator fans are bad even though that they work with an independent 12VDC. Thought not impossible I guess.  I read that the third sensing wire on each tells the motherboard that the fans are spinning, perhaps the fans work but do not send back the sensing which is causing something, again hard to believe.

I probed the LM324 while the fridge was idle and when it called for cooling.  I am no electrical engineer or know the exact functioning of a quad op amp so I do not know what the results show. It does get 12VDC, output pins it has 12VDC while idle and that drops to around 1 to -1 when on.  + and - for each amp seem to be not be consistent across the four when idle. When on they have approximate equal - values for each pair per amp. GND goes to 4.5V and the 12V in goes to -9V.

Perhaps some know if this is correct function and if so then maybe a new mother board is called for.

Offline ifixit

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Re: No power to ALL Evaporator Fans
« Reply #5 on: December 06, 2012, 03:21:21 PM »
I was measuring the op amp voltages incorrectly. They now seem to be fine, I think. What is more interesting is that the fans now run and I have power at CN75. I have no idea what occurred to make it work.

Is it possible that running the load condition or the self diagnostic or running the manual operation of compressor and fans somehow got them working now that it was deiced and they would not have started to work until that was done?

Is there some sort of clearing the fault codes that goes on when running the diagnostics from the control panel that would account for things to seemingly be working properly again?

Offline niobrara

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Re: No power to ALL Evaporator Fans
« Reply #6 on: December 06, 2012, 10:18:02 PM »
No

Offline sid6581

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Re: No power to ALL Evaporator Fans
« Reply #7 on: December 11, 2012, 12:19:13 PM »
I've been looking all over for this service manual as well - could someone please send it my way? Thanks!

Offline AJ

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Re: No power to ALL Evaporator Fans
« Reply #8 on: December 11, 2012, 01:06:45 PM »
I've been looking all over for this service manual as well - could someone please send it my way? Thanks!

Sure, here you go.
Samsung RF265/266 AB Refrigerator Service Manual

Hope that helps.

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