32 inch LG Television Model 32LH20R Dead, Now Repaired
I received a phone call from my neighbor who wanted his television checked by a technician. I passed by his place, ushered in and shown the television. I applied the power and television was dead with no sign of life. I decided to take the machine to my workshop for further testing. Once on the workbench I opened the Television and once the cover was removed I decided to begin by troubleshooting using my eyes and therefore scanned the three board, Power board, motherboard and the inverter board as can see here below.
I was not happy with the power board since I noted two capacitors with top
part slightly swollen and this is not good sign for capacitors as you can see below.
I replaced the two capacitors and since they are used to filter the inverter circuit line, I have high hopes that this could cure the problem. After replacing the two capacitor rated 1000uF/35v with 1000uF by50 volts, I decided to power the machine and check the progress. I noted the machine is now powering on but shut down immediately.
I checked the ESR of all the capacitors on the power supply, motherboard and inverter board and all tested okay. I decided to pursue the inverter circuit since the faulty capacitors were filtering that line and everything seemed okay according to my meter.
I decided to concentrate more on the inverter high voltage transformer and all looked okay to my eyes, no burnt areas or coils. I therefore decided to check the health of each transformer using my homemade fly back tester and I found one transformer where the fly back tester did not have any lights. I pulled my meter and tested the primary coil and was found okay, I tested the two secondary output and found one output was open circuit.
I found the coil was open just near the connector and did the connection using a very thin wire.
I once again decided to re-test and see if there is any progress and this is what I saw. The television came back to life smiling and praising for another chance to live.
Thank you guys
Stay safe
Humphrey Kimathi is from Nairobi Kenya and the author of:
1) Lcd-Led television repair guide
2) Microwave Oven Repair Made Easy
3) CRT Television repair course
4) Basic Electronics Course For Beginners
5) Basic Electronics course.
He is also a blogger at Electronicsrepairmadeasy.com
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Albert van Bemmelen
June 23, 2021 at 12:48 pm
Nicely done fix Humprey! These HV transformers luckily will become lesser used because newer LCD Led-backlit models obviously no longer need those.
Parasuraman S
June 23, 2021 at 2:00 pm
Well done, dear! 'The television came back to life smiling and praising for another chance to live', well that says it all!
Lewis Spedding
June 23, 2021 at 6:54 pm
Well done Humphrey. I have done a similar inverter transformer check with an LCD TV. If I remember the secondary resistance output should be approx 900-1k ohm. Great repair
Babu M S
June 23, 2021 at 9:51 pm
Fantastic repair work learned from your article.Thank you very much for sharing.
Yogesh Panchal
June 28, 2021 at 4:21 pm
Good JOB! Sir