Fridge control board

[Kadra]

Brand: Frigidaere
Model Number: FPRH19D7LF1
Main Symptom: Freezing
What happens & when: Its been going on for over for six weeks.

Error Code (if any):
Parts or tests already tried: new Thermister, new control board
Photos / video link:

So my frigidaire fridge like six weeks ago started freezing. called in a repair company, they got a new thermister (Part Number: 297110400) and a new control board. ( AP5177035 (297326500). said that my fridge is a basic unit and simple, just change out the part. He installed both parts. Needless to say, the fridge didn’t work-fridge turned on, but compressor didn’t kick in. He came back a few days later and said we need to order a new control board. That took another week came back and installed the new control board, it kicked in, compressor worked, but fridge kept freezing. Came back out and said he will order a new part, but that was gonna take another ten days, so I opted to order my own part from Appliance pro to install myself since by then its just a plug in. My part came in first, and it worked for like ten days, but then the fridge started beeping giving a faulty temperature read of 85 and then continued to freeze. I requested a new part from appliance pro, which I received a few days ago. My appiance guy came in the meantime with his part which is also did NOT work! so they were gonna order a fourth part, at that point i said, this is taking too long, I may just buy a new fridge and got some of my repair money back.
Anyway, the new control board from Appliance pro does NOT work. It doesn’t do anything for the fridge. Just turns it on, but doesn’t kick on when the temperature in the fridge is like 50. ao at this point (3 control boards - from appliance company) and two from (appliance pro) are simply not working or fail.

For reference, I did turn off the circuiti breaker of the fridge before installing the parts, then turned the circuit breaker back on.

The newest part from appliance pro didn’t kick in, but when i changed back to the first part from appiance pro, it kicked in but ofcourse it’s not reading the temperature in the fridge.

Could i have five failed control boards from two different vendors?? what else can I try?

[WilliamM_APP_Team]

Is the light installed on this unit the OEM light or has it been replaced with an alternative? I ask because there are alternatives that have a different current draw from what the manufacturer specs recommend and it can cause a control board to act erratically.

[Kadra]

thank you for replying!

Everything is orignal except for the control board and the thermister. I’m attaching a picture o the board, i installed it into the original “cabinet” that houses the board, and i plugged it into the original cables that came with the fridge also pictured.

What you are suggesting makes sense since five boards didnt work, and one is on and off. any advise on how i can fix that?

[WilliamM_APP_Team]

For testing purposes, what happens if the LED lights are removed? Also, it appears there is a slight gap in the wire connection near the ceiling. Is there any room for it to push in more?

[Kadra]

I went ahead and removed the LED light, the fridge did not kick in unfortunately. the compressor didn’t kick in i waited a good 20 minutes.

[WilliamM_APP_Team]

@Kadra

FPRH19D7LF1

If you would not mind, would you be able to test from the black wire to the white wire for Volts AC with a multimeter? What voltage reading shows up? Once that is identified, if the power supply cord could be unplugged, the 7-wire connection at the main control disconnected, and the red wire tested for resistance to the black wire. What resistance reading shows up?

[Kadra]

the first pic-white to black voltage is 123. 5 AC V

after unplugging the fridge (removing power from circuit breaker), Red to black resistance, is 82.3 K ohms

Picture 3 red to black resistance with power CONNECTED, 114.3 K Ohms.

[WilliamM_APP_Team]

@Kadra

FPRH19D7LF1

The thermistor circuit appears to be good and the voltage is certainly good. Using the control that had the working LEDs but was freezing everything, there should be a model ID displayed for 5 seconds when you first plug the power cord in. What model number does it display?

[Kadra]

There is no model number that shows up, i’ve seen those installed multiple times the only thing that shows up is the number 3. Attached is the picture.

[Kadra]

we plugged in the part, compressor started, temperature reading in fridge (on control board says high temperature-83), but its really like 55. Fridge kept cooling it reached 42, but fridge kept going, and so we measured the ohms- heres a picture. Does that make any sense?

[bigbuck1]

See if any of this is helpful. http://www.uncleharrywizard.com/nephewclub/wizardfrig/electrolux-frigidaire/5995573499-19cuft-all-refri.pdf

297367100.pdf (364.2 KB)

297110400 Thermistor.pdf (29.5 KB)

[Kadra]

Thank you for sharing the docs. Upon looking at the termistor document, here is what we found.

Our fridge froze overnight, so it didn’t stop after reaching the desired temp. we measured the resistance with the temperature displayed in the pic-around 24 degrees. that does not line up with the what the attached thermister document states.

297110400 Thermistor.pdf (29.5 KB)

[WilliamM_APP_Team]

When testing the thermistor resistance, the wire connection going to the control board would need to be disconnected. With the control side being connected, there could be a false reading.

[Kadra]

Then this reading is done correctly as it is not connected to the board.

My understanding is that for the warrantee to come into effect, i would need to trouble shoot this. .is there anything else we need to do or is this another faulty control board?

[WilliamM_APP_Team]

@Kadra

FPRH19D7LF1

If I am reading the measurement correctly, it looks like it is 13.2 Ohms instead of K-Ohms. This would indicate an issue with the thermistor since 13.2 Ohms are going to read a significantly higher temperature than the refrigerator could safely be at. 297110400 Thermistor | Genuine Frigidaire OEM In Stock

[Kadra]

Okay, the mystery continues. We bought from appliance pro a new thermister. We checked the oms of the old thermister (which was technically new since it was replaced by my appliance repair man), and it was giving wrong readings. like 10 ohm or so. We installed the newly bought thermister, measured the oms, and it read 10.2 Kohms which is in line with the chart above. Temperature was around 70 or so degrees in the fridge since it was off for a long time.
I proceeded to add the latest board from you guys, and as soon as I plugged in, the compressor kicked in normally, but the board was reading 83 degrees (high temp) in red. Kept the fridge running for 2-3 hrs, it reached 32 and i knew then that it was going to go to freezing, because the board kept saying 83 degrees, high temp and that signals that the compressor should keep going. I unplugged the control board, read the ohms at approx 34 degrees, and it was around 37 Khoms, which is in line with the chart, so I know my thermister is working. Could the control board be shot? what else would make the board still give me high temp reading considering the fridge temperature is almost at freezing?

[WilliamM_APP_Team]

If you test the thermistor wires running from the control to the same wire points at the other end, do they have continuity a low resistance continuity? If they do, the only thing I can go back to is the control board. 297326500 Control Board | Genuine Frigidaire OEM In Stock

[Lee76]

@Kadra and @WilliamM_APP_Team,

I have a Frigidaire FPRH19D7LF1 standup refrigerator unit. I’m also having the same exact problem you are having…

I’ve tried two control boards and three thermistors. Nothing worked for me.

I really would like to figure this out.

I even went out and purchased a Yolink remote sensor to monitor the temperature to see if it could have been my gasket causing the temperature to not be stable, but my temperature holds temperature inside the refrigerator.

I also measured my defrost thermostat and the readings are good. Low resistance .1 to .3 ohms when cold.

I did notice that my refrigerator has a 12-14 degree delta from the temperature setpoint on the control board. So when I set to 38, the refrigerator will cool to 22-24 degrees and when I increase it to 40 it will cool to 26-28 degrees

As frustrated as I was, I decided to move the thermistor closer to the evaporator fan suspended in the air. I was able to close the delta gap to 10-11 degrees. So when I set the set point on the control board to 40, the refrigerator will drop to 29-30 degrees.

I’m not sure what to do at this point. Frigidaire support is horrible. They tell me to call a tech and when I did, they wanted to replace the control board and the the mister, but I already did that so what’s the point?

I am tempted to purchase a resistor with a 2K loan value and connected in series with the thermometer to provide that additional offset because there’s obviously something wrong and I do believe it’s in the control board.

I believe Frigidaire has changed the specs on their control board thus increasing the delta for the refrigerator unit, causing it to cool beyond the 2 1/2° temperature from the setpoint.

[Lee76]

@Kadra @WilliamM_APP_Team

Stay with me here folks… I might be onto something…

I did some more troubleshooting and went the extra mile.

I powered up my old board on a test bench and stuck a known good thermistor on the side of an iced plastic cup. The thermistor was connected to the board as described on the diagram. The temperature on the inside of the cup was 32.5 degrees, and I measured the thermistor resistance it was 26K, that equals 32 degrees.

The output pin to the compressor was being monitored by a voltmeter.

Now that I know the resistance and the temperatures, I did the following:

Set the temp setpoint to 42 degrees and powered off the control board (CB).

Remember, my temperature on the plastic cub is approximately 32 degrees +/–0.5 degrees.

Set CB temp to 42 and the compressor off (voltage output from the CB was 0 volts)

Set CB temp to 41 and the compressor off (voltage output from the CB was 0 volts)

Set CB temp to 40 and the compressor off (voltage output from the CB was 0 volts)

Set CB temp to 39 and the compressor off (voltage output from the CB was 0 volts)

Set CB temp to 38 and the compressor on (voltage output from the CB was 110 volts)

At this point, I tried to increase the temperature back up to 42, but the output to the compressor wire was still showing 110v.

This pretty much proves that my old control board is bad unless you think otherwise.

My new control board behaves the same way. I think Frigidaire is selling defective control boards with tolerances that are out of spec.

Your thoughts….

[DavidP_APP_Team]

Good information! It looks like you may be right, it won’t be the first time