No Display Problem Solved In TCL Android LED TV Model 32S5202
This TV was brought by a new customer as per recommendation of a regular one with the complaint that there was no display. I switched on the TV and checked whether the TV was getting on. It was and the backlight remained lit without any display.
I opened the TV and cleaned inside as usual and checked the voltages on the Scalar Board such as VGL, VGH, AVDD, V-com & VCC. The VCC (12V) and subsidiary voltages such as 3.3 & 1.8V were present. But other voltages from the IC SM 4186 were absent. This TV was using a panel with a single COF.
The case evidently was an internal panel short. First let us find out how to identify the CKV lines in a scalar board.
Perhaps the following link of a video would be of some help:
That video also shows how to measure the VCC and V-com voltages. Generally the CKV lines are like in the following picture:
There are parallel lines of these on the other side of the COF too. Let us have a look at that:
In the above picture please look at the red spots marked by my techie friend. The step is to find out the short using a multimeter. Let us give some numbers for the zig zag copper dots on the area. You can notice that there are 9 zig zag spots. Starting from the left, let us give them 1 to 9. Therefore the red spots marked are on 5, 6 7 & 8. We need to check the resistance between 5 & 7 and 6 & 8. It should show in meg ohms. In this case, the reading was 470 Ohms confirming a short between 6 & 8.
The next step is to isolate which side of the panel was short as these lines parallelly enter from both sides as mentioned earlier. For that we need to take a chance by cutting the four lines nearest to the starting point of the COF where the lines enter. Kindly see the yellow bar on the pictures. The video in the link given would show you how to do that. The next step is to just cut one line out of the shorts located and see whether the display was back. I cut single line track (8) and found that the display was back, which definitely was a sheer luck. Then cut the other three lines adjacent to it too. What to do when it did not?
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We may have to rejoin them for which the cutting should be in a slanting mode lifting the cut portion to just detach the continuity. This has to be practiced well and should be done under X10 lens with proper lighting. Let us have a look at the first result that I got on cutting the single track:
Then I cut the rest of the three tracks also similarly and made the cutting permanent as there was no need to rejoin them. Why the other lines were cut? The internal short happens due to carbon deposits formed inside the panel between the tracks. This can soon spread to the adjacent tracks too and that is why we cut the entire section. Though the resolution would get affected, and any heavy load such as from an HDMI would blow the other side of the panel also soon, the TV can be used in wireless mode directly receiving the internet as it was an android smart TV. I kept the customer informed of the limitations without divulging the info about work done to restore the display.
He was ready and I charged only a small amount just to cover my expenses as there was no guarantee for how long the TV would work in this condition. This type of single COF panels have short life and chances of a total failure cannot be ruled out. After testing the TV for sufficient time, I closed the back cover and here you have a final picture, which of-course was good enough for a naked eye:
Mission accomplished with satisfaction of work alone getting collected, leaving a melancholy for obvious reasons!
This article was prepared for you by Parasuraman Subramanian from India. He is 76 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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You may check on his previous article on The Risks Of No Display Complaints In TVS – XIAOMI L43M6-ES & PHILIPS 43PUT6002/56
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Albert van Bemmelen
April 11, 2026 at 2:37 pm
Sorry but this again was too complex for me to understand. I only understand it is about removing the shorted line connections but still have no clue how it exactly was done here Parasuraman. And the explaining video was no help either because the explaining voice was hard to follow. I do not even know what CKV lines exactly means?
These tv repair articles are way too difficult to understand for beginners when it is about repairing these large defect COF tv panels. Why I prefer the usual electronic repairs that do not have such high failure risks. And is the reason why I restrict myself from taking on tv repair as a decent hobby.
Parasuraman S
April 11, 2026 at 9:53 pm
Kindly check this link: https://www.ornatepixels.com/2024/02/what-is-ckv1-ckv2-ckvb-ckvb2-and-common.html
Hope this helps! Many thanks for your expert comments, dear Albert!
Albert van Bemmelen
April 12, 2026 at 12:07 am
Thanks for that explaining helpful link, dear Parasuraman!
Yogesh Panchal
April 11, 2026 at 3:20 pm
Good Job!Sir,
Hard to find Panel CKV failure rate by Panel Brand.
Parasuraman S
April 11, 2026 at 9:54 pm
Yes, most of the panels are manufactured by a few who are global suppliers. Many thanks, Yogesh Bai!
Mark J
April 12, 2026 at 2:35 am
The TCL brand of electronics are on the lower end. They are problematic. I am kind of like Albert. I rarely do tv and monitor repairs. Great job on the repair. Thank you again for sharing Parasuraman.
Parasuraman S
April 12, 2026 at 9:59 am
Oh, I see! So, Alberts are increasing in our forum! (LOL) Many thanks for your comments, dear Mark!
Uniqueness and challenges are always very thrilling and that is why I take up such jobs! It will keep our interest and enthusiasm very sharp and alive!
MP
April 12, 2026 at 9:27 pm
Doesnt it seem to me like general TV panel COF work is way much more managable than TV panel LED lights replacement ? Thats my study opinion of the two shiver-inducing options. One more assessement observation, the 1000(th) mark article is approaching at lightening speed. But every so oftenly, thanks God, I grasp only what possibly I can. Thanks, Eng. Parasuraman.
Parasuraman S
April 13, 2026 at 5:34 pm
Many thanks for your comments!
Imoud.O
April 13, 2026 at 3:41 am
Good repair sir,I once did this kind of repair on this type of panel and the panel came to life again with good picture, unfortunately it only lasted for just two months and collapsed again beyond repair.
Parasuraman S
April 13, 2026 at 5:35 pm
Yes, that's the problem! We cannot predict how long it will last! Many thanks for your comments!
Muykit
April 13, 2026 at 3:30 pm
Good article. Understanding some old nice articles may be difficult when accomponying pictures or videos are removed. I try extremely hard to understand what you write before resorting to other stated references. Engineer, I belong to the minority old school. Old habits die hard. Some times I practically have to write article notes for safe keeping because who knows what will happen to my dependable phone later ?
Parasuraman S
April 14, 2026 at 7:00 pm
It is a good habit to write down all important details and preserve it as a hard copy. Many thanks for your comments!