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Forum Index => Refrigerator & Freezer Repair => Topic started by: zmann96 on June 15, 2020, 12:58:42 PM

Title: Green Light flashing on PCB board
Post by: zmann96 on June 15, 2020, 12:58:42 PM
I have an LG  LFX28978SB  it runs for about a day with the freezer at 11 deg and the box at 36deg. the compressor is just warm not hot at all. while it's running I have the green light blinking on the PCB board. Once it shuts down I get a clicking noise from the PCB area behind the cover just like a car's directional. I'm assuming it's the compressor.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 16, 2020, 05:17:35 PM
I guess this was a waste of time. No help here.
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 17, 2020, 04:47:43 PM
Your fridge has a LG linear compressor and LG has new updated compressor but it also requires firmware update jig to flash the firmware on the mainboard.
If you can do it yourself might be worth it but how old is that fridge in most cases it turns into a exercise in frustration doing sealed system work on LG.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 17, 2020, 05:28:16 PM
Yeah, it's a 2000 by the serial number.  I hate to have to sink 500-600 into a 20 YO fridge.  One local service company I called said they could don a diagnosis for $80. He said with what I told him it could be the PCB board.

Thank you for responding was getting disappointed
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 18, 2020, 08:10:36 PM
I don't think it is 20 yrs old if it is the model number you posted this pdf has a date of 2010.
So it's still 10 yrs old approx.
Usually on the data decal it shows mfg date and country.
Did you remove back cover by the compressor and take a pic of the numbers on the compressor? Also was the condenser coil very dirty?
LG has 10 yr warranty on compressor but labor only covered for 5 yrs so even if it was under warranty you would be spending about 500 in labor to replace compressor.
But you said it was cooling normally sometimes which usually does not happen when the compressor fails on LG.
You could try and find a PCB board on Ebay or other sites used and take a chance see if it works before junking the fridge.
I have seen people selling LG parts and even giving away entire fridges on Facebook marketplace and craigslist.
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 18, 2020, 10:03:26 PM
Is the compressor decal FC75LANE ?
If it is there is a way you can hot wire it to test the compressor but you have to be very careful.
You can use a old power cord for a computer that has black white and ground wires, solder some insulated alligator clips to each wire. (Or you can use butt connectors that fit snug on the pins on compressor and only crimp onto the wire side).
Unplug compressor harness and connect black and white to the pins on compressor (make sure you use the same pins the 2 wires in the harness were connected to, one pin is not used for anything).
Clip ground to the metal of compressor so its grounded.
Stay back in case one clip falls off and plug in the test cord.
The compressor should run with 115 volts AC directly connected to the pins.
If it runs and starts to cool then you should be able to only replace the inverter PCB  board to fix the fridge.
This only works on the FC75LANE compressors.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 19, 2020, 04:22:23 AM
Gee, thanks for all this help.  You know I didn't think it looked to be 10 YO. It was in the house when I purchased in January. the serial started wit 00 so I thought that meant 2000.  I've attached the tag photo. The condenser coil is clean. Yes the compressor is  FC75 LANE.  I just ordered a PCB board on Ebay to rule that out.  I'll try that Compressor test. It does run and cools really well, the freezer at 11 deg and the box at 36 deg for about 24 hrs. until it shuts down.
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 21, 2020, 03:16:50 PM
If you replace that board that is clicking it might fix it. I had same problem on different model LG that uses that same compressor FC75LANE and the board was clicking so I replaced that board and it resolved the problem.
Other LG's that use compressors that end with LANA have had serious compressor issues and require the newer updated compressor and software update on the mainboard (LG changed the design so only one large PCB now).
They should have stayed with the original LANE compressor and separate boards like you have it was more reliable design.
Let us know how you make out after you change the board.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 21, 2020, 06:15:58 PM
Thank you, it should be here by Tuesday, I'll definitely let you know.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 25, 2020, 02:15:11 AM
The board came in yesterday and I installed it. The fridge started up, as of 7pm last night no green light or clicking. I'll check again later on and let you know if it's still good, it ran 24 hours before it shut down with other board.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 25, 2020, 03:17:14 PM
It's been running over 24 hours, freeze cold and box at 36. No green light or clicking.  I'll let you know how it goes for another day. Thank for your help, much appreciated.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 26, 2020, 06:23:48 AM
Still Running  Freezer at 8 deg and box at 35. I think it's fixed   :cheers: :thanks:
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 26, 2020, 10:26:41 AM
Good to hear! The inverter board is usually what fails on the new fridges that use variable speed compressor. The other brands of fridges use Embraco compressor with a control board next to the compressor and the inverter board fails on those.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 26, 2020, 12:23:44 PM
I really appreciate all your help and time spent helping me.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 30, 2020, 02:47:27 AM
The fridge went down after about 4 days. It coded CF. I had purchased a used PBC board that was supposedly tested. I was planning on buying a new one if that solved the issue. The coil looks clean. So I'm wondering if it's the PMC board, the coil or a blockage. Is there a way of testing the board with a simply meter?
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 30, 2020, 05:36:29 PM
I think CF code is Condeser Fan which is the fan that cools the compressor and condenser coil. This could be making compressor overheat and shut itself down. Did you notice if the fan spins all the time when compressor is running? These fans are the new brush-less DC fans that send a feedback signal to the mainboard so if the signal is not seen the mainboard sets the code.
The compressor inverter board does not set any codes on the front of the fridge it only blinks the led on the board you replaced.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 30, 2020, 05:54:51 PM
I did notice the fan running and the fan was replaced recently. I didn't really pay much attention for the duration when the compressor was running if the fan was running all the time. I sent the used board back. I'll order a new one and start over. I did notice that the green light was not blinking on the PCB.  I'll let you know after I get the new board and start it up.
Title: Re: Green Light flashing on PCB board
Post by: houptee on June 30, 2020, 06:19:08 PM
The board was probably fine that runs the compressor that board does not control the fan. The main board turns the fans on and off and monitors them so any codes you see with F is a fan code like IF is Ice Fan for icemaker FF is freezer fan and RF refrigerator fan etc.
You could have a bad fan even tho it was replaced or the connector is damaged or wire got pulled out of the connector they are thin wires so look carefully maybe with magnifying glass to be sure all wires are good. If someone pulled on the wires to unplug it they could be damaged.
There is usually a wiring diagram decal on back that shows what connector on the mainboard powers the condenser fan so look at that connector also make sure it is plugged in tight.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on June 30, 2020, 06:22:25 PM
OK, I'll check these things out. Thank you again
Title: Re: Green Light flashing on PCB board
Post by: houptee on July 04, 2020, 07:39:42 PM
Found the service manual for that fridge.
Title: Re: Green Light flashing on PCB board
Post by: zmann96 on July 04, 2020, 09:44:00 PM
Awesome thank you. I should have the new board Monday?
Title: Re: Green Light flashing on PCB board
Post by: shillion on July 09, 2020, 03:36:24 AM
I don't think it is 20 yrs old if it is the model number you posted this pdf has a date of 2010.
So it's still 10 yrs old approx.
Usually on the data decal it shows mfg date and country.
Did you remove back cover by the compressor and take a pic of the numbers on the compressor? Also was the condenser coil very dirty?
LG has 10 yr warranty on compressor but labor only covered for 5 yrs so even if it was under warranty you would be spending about 500 in labor to replace compressor.
But you said it was cooling normally sometimes which usually does not happen when the compressor fails on LG.
You could try and find a PCB board on Ebay or other sites used and take a chance see if it works before junking the fridge.
I have seen people selling LG parts and even giving away entire fridges on Facebook marketplace and craigslist.
be me