Author Topic: LG LFC21776ST / 00 Compressor wont start  (Read 1190 times)

Offline houptee

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LG LFC21776ST / 00 Compressor wont start
« on: September 01, 2013, 10:12:31 PM »
Hi guys,

I have a LG model LFC21776ST / 00

It was in a few inches of water in Sandy, my neighbor threw it out it was less than a year old so I grabbed it.

The PC Board in lower back by the compressor inside a plastic case, I believe it is a power supply board, was half submerged. I removed the board and sprayed it with wd-40 and brushed it good with a old paint brush then blew it off with air hose. It ran fine for a week then it stopped and the board just clicks every few seconds and led blinks on the board.

I jumpered power directly to the compressor pins and it starts up fine.

The board is around $100 bucks with shipping so I was wondering if it can be troubleshooted and repaired since it does not have many components on it and the chips should not have been damaged from water only the relays may have water inside but they appear to be sealed very well with epoxy around the pins. I tried to jumper the relay pins but no luck same clicking.

The board part number is EBR64173903

Anyone know how I can test it to be sure it is that board because I dont think I can return it if it is not the problem.

The rest of the fridge works and the condenser fan kicks on and all digital temp controls work etc just the compressor wont kick on.

Thanks for any advice.

Offline john63

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #1 on: September 01, 2013, 11:03:57 PM »
Count the number of times that the light blinks---7 times?

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #2 on: September 02, 2013, 12:30:59 AM »
It seemed to click constantly last time I tried messing with it a few weeks ago. Tonight I plugged it back in and it did not click at all, the condenser fan came on but compressor still did not start. Interior fan runs and lights work just no compressor running.

Is the number of flashes on the led a diagnostic code?

Thanks

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #3 on: September 02, 2013, 09:44:41 AM »
PS:
This unit has the Linear Compressor and I do not see any PTC device, the wires connect directly to the compressor pins from the lower board that had been half submerged in the flood water.

I am searching for the manual but all the LG ones on the AJ google drive seem to show a PTC circuit.

Does anyone have a linear compressor service manual or training documents on them?

Thanks

Offline tgoods

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #4 on: September 02, 2013, 12:09:18 PM »
Here's a manual for your fridge. If you order any parts from the affiliates, Repairclinic.com or Appliancepartspros.com, you can return the parts for any reason within a year. 


I haven't worked on a linear compressor fridge yet, but there's something interesting from the manual I want to note. The compressor looks just like a regular compressor.  There are three terminals.  The resistance reading from the lower pin to the upper left pin should be 6-8 ohms.  The upper right pin is not connected to anything, so the resistance to it will be infinite.  The reason I want to note this is because, if you didn't know this, you might assume the compressor is bad.

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #5 on: September 02, 2013, 01:44:08 PM »
Thanks!

That manual is good but very poorly written.
It basically says if you have any blinking led on the lower board that controls the compressor to replace the board (after checking compressor resistance).
I hot wired the compressor and it runs so I guess it must be the board.
Wish I could fix the board its probably one component that went bad but the manual doesn't go down to board level diagnostics so no way to probe out voltages at the board to figure it out. Guess its not worth the labor time to do that anyway since its only $87 for the board.

Offline krazytech

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #6 on: September 02, 2013, 02:57:52 PM »
I hot wired the compressor

Please tell how you "Hot wired" a linear compressor and was it a FC75Lane Self
Modulation CVCF or a FC90LANA compressor VVVF?
Check the Basics first!!! Read the Manual !!!Buy the tech a Beer!!!

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #7 on: September 02, 2013, 03:19:00 PM »
It only has 2 wires hot and common from the board to the compressor. I unplugged them and applied 110v to hot, and ground to common, with test leads and the compressor ran. I only ran it for about one min like that.

I got the fridge free so figured what the hell try it before I spend any money on boards etc to make sure compressor is not bad.

Hope I didnt damage it but it started right up and sounded fine and that was without any start capacitor in the circuit just 110v.

Are linear compressors powered by DC voltage not AC from the control board?

Some of the new mini split a/c systems say inverter compressor technology is that same as these linear refigerators?

Offline krazytech

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #8 on: September 02, 2013, 03:54:41 PM »
No It is compress is AC.. but a controlled  AC by the inverter.The inverter takes AC to DC  then back to a controlled AC..starting voltage is 85v with normal run at 185v the inverter also controls Hz.
Check the Basics first!!! Read the Manual !!!Buy the tech a Beer!!!

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #9 on: September 02, 2013, 04:53:17 PM »
Do you have any training materials about linear inverter compressor technology that you can post or place it in the AJ Google Drive?

I want to learn about how it works and troubleshoot it but I cannot find any technician training info online or any useful video training on youtube.

When I searched this forum for "linear compressor" only 2 posts came up one being mine.

Thanks!

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #10 on: September 03, 2013, 08:38:06 PM »
The compressor is a FC75Lane.

I have not plugged the unit in for a while since the day I hot wired the compressor to 110v, ran it for a min or so, then put it all back and it was still just clicking repeatedly and flashing the led on the board.

Today after reading the manual tgoods was so kind to provide I plugged it in and no clicking at all but compressor will not run, so I put unit into test mode by pressing the button on the main board once, which is supposed to run all fans and the compressor.
Everything runs except the compressor, PWB board does not click at all and no led activity.
The part is showing out of stock on both sites repairclinic and appliancepartspros and a few other sites I tried so I assume this is a common failure item and maybe just a coincidence and the flood water has nothing to do with it?
It did run fine when I first cleaned the board with wd-40 after the hurricane.
Anyone else replace that board before for same symptoms?
P/N is ABQ73004302

Offline VOGUSLAVKY

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #11 on: September 17, 2013, 08:05:53 AM »
Make  sure you not in demo mode.

Offline houptee

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #12 on: September 27, 2013, 11:04:31 PM »
Update:

I ordered the compressor control board assembly from RepairClinic.com and they showed a new part number that superscedes the original P/N ABQ73004302 the new one is ABQ73004304

I guess they made some updates to this board hence the new part number.

It fired right up and compressor runs fine now.

I was afraid I may have damaged the compressor by hot wiring the pins to 110v directly to test it but seems to be working and it has been 4 days running so far.

Thanks for all the advice and the service manual!

Offline krazytech

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Re: LG LFC21776ST / 00 Compressor wont start
« Reply #13 on: September 27, 2013, 11:29:39 PM »
     No damage at all that is how the factory wants us to test. 10 warranty on them hardy compressors.. Voltage from 20v - 200V. will harm this compressor.. if you move it or lay it down. and start the compressor and it makes a load noise. you may have too hit the fount of the compressor as the magnet my stick too the side.


Cool Refrigerator for the price of a control board.

Check the Basics first!!! Read the Manual !!!Buy the tech a Beer!!!

 

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