How To Repair LG LCD Monitor- No Display With Good Power Output Voltage
Fault Symptom: No Display With Good Power Output Voltage
Customer walked into my workshop with an LG Flatron W1643c Monitor with above said fault symptom. So I have received the monitor for repair and given token to the customer about estimation period.
In order to confirm the problem I have attached the power cord to the monitor and powered it On. I am not getting any symptom of life, LED power indication was not lighted up. So I opened up the casing and do the visual inspection first on the circuit boards.
This monitor is using external power source working on 12V power adapter. First of all I have checked power adapter for 12V and found OK. Now checked PCB by solder side seems ok no burning mark and no dry solder.
Now I turned the PCB on component side, look what I seen.
There was one Square IC marked with U201 some of the pins look like burnt. So I have checked under magnifier glass and it was not burnt marks but some sticky substance was there.
I cleaned the pins of IC with turpentine and applied some fresh solder. After the cleaning process, now I decided to check the status of monitor by applying power, hence I have connected the power cable and turning on the power.
The LG LCD Monitor came back to life with power LED indicator was glowing.
I found the pin out detail of the IC “NT68167HFG” on the net as follows. Marked with red box pins cause shorting on the logic board.
Note: The power LED signals are coming from this MCU IC so if this IC does not work means the LED would not light up. So you may be thinking it was the fault of the power supply. The best way to confirm is to measure the DC supply input voltage to MCU IC.
This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.
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Tito Kanshulu
August 9, 2016 at 2:28 pm
Good work Yogesh. Should we say that those sticky substances, found on the ic,were in the form of glue which shorted the pins of the ic or some substance dropped on the ic?
Yogesh Panchal
August 12, 2016 at 12:51 am
Mr.Tito,
Thanks for the comment.
I think it may be due to some insect droppings/urinate or like,though i did not find any insect residue because some one who has open this monitor for repair before me has cleaned every thing from in side.
gaurang Patel
August 7, 2018 at 12:24 pm
hello sir i have lg LCD Lm156wh1. which has the same ic nt68167h. i m getting problem in LCD when i connect the VGA cable and power cable it shows the LCD red light blinking continues and on screen it show blank (black). i remove it out and only connect the inverter cable it shows white light. when i connect the data cable it continues blinking the red light. so what could be the problem..
please sir give me the solution if you have.
Albert van Bemmelen
August 9, 2016 at 2:36 pm
If the sticky substance that caused the shorting Pins came from some kind of insects we better prepare ourselfs for an invasion? According to previous articles they cause for millions of damage on repair costs. Good job Yogesh and thanks for the schematic.
Yogesh Panchal
August 12, 2016 at 12:52 am
You are right Albert,
thanks for comment.
Waleed
August 9, 2016 at 4:35 pm
good article. thanks for sharing
Yogesh Panchal
August 12, 2016 at 12:53 am
you are welcome Waleed,
Thanks for comment.
Parasuraman S
August 9, 2016 at 5:10 pm
Your expertise is what made the troubleshooting so simple and easy!
Yogesh Panchal
August 12, 2016 at 12:54 am
Sir,
Thanks for comment.
Anthony
August 10, 2016 at 6:23 am
Great repair Yogesh, Thanks for sharing.
Yogesh Panchal
August 12, 2016 at 12:54 am
Anthony,
Thanks for comment.
Gary Gemmell
August 10, 2016 at 9:26 am
Nice quick diagnosis and fix - if only all fixes could be like this!
Well spotted Yogi!
Yogesh Panchal
August 12, 2016 at 12:58 am
Mr. Gary,
yes the the weight of "could be" is more than Human expectations.
Thanks for comment.
Luciano Khware
August 10, 2016 at 2:41 pm
Yogesh,
Thanks for sharing your repair experience!!
Yogesh Panchal
August 12, 2016 at 1:00 am
Mr.Luciano,
Thanks for comment.
suranga bandara, Suranga Electronics
August 10, 2016 at 4:43 pm
The quick trouble shooting. nice repair Mr-, Yogesh,
Thanks for sharing it with us.
Yogesh Panchal
August 12, 2016 at 1:01 am
Thanks Suranga.
reza
August 11, 2016 at 4:50 am
Hi
Very Good
Yogesh Panchal
August 12, 2016 at 1:02 am
Mr, Reza
Thanks for comment.
Raju Varghese
August 14, 2016 at 5:06 pm
Hai Yogesh,
Good Day!!!
good attempt and excellent troubleshooting .
Thank you for sharing.
Yogesh Panchal
August 16, 2016 at 12:07 am
Raju,
Thanks for the comment.
mohsen
January 18, 2018 at 11:10 pm
I have problem with my lg screen same like one in the topic , when i power it on it gives me a white screen then slowly go to black color and check signal cable appear but the right side still white , i need help plz
JagdishChPandey
November 11, 2018 at 6:47 pm
Dear Sir I want this board
Sreekumar
December 27, 2018 at 3:38 pm
I have LG LD650P TV. the mother board has been replaced twice, now its not even in production. the display panel is good. how do I convert this to a monitor ?
MD ABDUUS SALAM MIR
October 26, 2019 at 11:00 am
hello sir i have lg (Flatron W1643c) my problem VGA Cabel Conet......RISPARAIO ENERGIA....PLZ HELPH SIR
Smita Muley
November 16, 2019 at 4:01 pm
Sir, I have lg flatron w1943c.
When i start the lcd it starts and again turns off immediately and repeatedly.
I opened the screen and removed all cables and put it back. Screen started working for a while and again when i started it it started to do the same thing. And there is no red light on the screen on/off button. What should i do?
Sanjit Biswas
December 24, 2019 at 10:21 pm
Can i buy above this green board
Pradyumna Panda
October 21, 2020 at 1:32 am
Dear Sir,
need the firmware for LG-W1943c. so kindly share me the software or the link to download the file for updating the firmware on my email id.