Don't Miss

DVD Player Turned LED TV Panel To White

By Jestine Yong on July 29, 2022

This LG dvd player was send to me with the complaint of being dead. I open it and observe the resistor fuse was burnt, power IC cracked and two tank capacitors opened.

The voltages of this power board are +12, +5, G. So I decided to check if the main board and mechanism side are functioning before I repair the power board. So I use another power board, tap +5, G,and +13.6V (suppose to be +12 though)and connected to main board, then power dvd and it came up.

So I connected the dvd player to my 32″led tv and powered the appliances. Guess what happened, tv came up and the screen immediately turned white with vertical lines, picture below:

I was surprised and confused, I don’t know what went wrong. Well, I thought tv screen got damaged on its own, so without being suspicious of dvd, I brought out my operational Sony portable 12.5″ CD,DVD,TV, FM RADIO player. This player has AV input and output, so I connected the dvd on repair to the AV input of Sony player and powered the two players.

The audio and video from repair dvd to Sony screen was good and clear for about 4mins, then suddenly the unexpected happened again: the screen of Sony player changed to white with vertical lines too. ( sorry I forgot to take picture of this). It was then it done on me it was the LG dvd player that damaged the two tv’s screens.

Now I am in a state of confusion, what went wrong? I can’t say. Perhaps if you have experienced such in the past and know what can cause this costly damage let us know please. What is your take?

This article was prepared for you by Imoudu Onwumah from Nigeria. He is 62 years old and has just 3 years experience in electronics repairs. I started career in hotel industry as a chef, but then I was doing repairs only in electrical repairs as a hobbyist. In 2018, I decided to learn about electronics which through Jestine’s electronics e-books and holding my hand, am an electronics techie today.

Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.

P.S- If you enjoyed reading this, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!

Note: You can read his previous article on Standby In LCD TV Repaired

Likes

(50)Dislikes

(1)

LED TV Repair

8 Comments

Parasuraman S

July 29, 2022 at 9:50 pm

If excess voltage is present in the video or audio output, it can damage the internal parts of the LED TV. You did not say what happened when the DVD connection was removed and another working input was given. Anyhow, the uController might have gone to protection mode. You have to check the VGL/VGH/Vcom/AVDD voltages on the T-cob or Scalar board after ensuring the main power supply is good. All the very best. This has opened some interesting investigations for you and I am sure you will succeed in restoration and writing another couple of articles in this wonderful forum!

Likes(6)Dislikes(0)

Reply
- Parasuraman S
  
  July 29, 2022 at 9:52 pm
  
  I also remembered one more point. Just check whether the video in to ground is showing 75 Ohms in both the LEDs. There are Zener protection diodes in it. These get short quite often. Do the same test on the DVD player too.
  
  Likes(5)Dislikes(0)
  
  Reply
Albert van Bemmelen

July 30, 2022 at 12:06 am

I think that it has to do with your direct AV wire connections, also known as COMPONENT, and some kind of too high voltage on your dvd video and or audio outputs. At best you could use an oscilloscope to examine the probably dangerous signals but only by using at least an 1 to 10 probe to avoid also damaging your oscilloscope inputs in the process. But before you do maybe also first measure the output voltage with your digital MM first. Normally that output voltage should be around 1V pp for video Composite inputs. And for LINE outputs −10 dBV (300 mV) at 10kΩ. Maybe see also => https://www.broadcaststore.com/pdf/model/793698/TT148%20-%204053.pdf
I hope you still will be able to repair your defect AV inputs.

Likes(5)Dislikes(0)

Reply
Imoudu.O

July 30, 2022 at 5:28 pm

Mr P.S and Mr A.B
Thanks for your contributions and advice,I will look to these suggestions.Have a nice day.

Likes(1)Dislikes(0)

Reply
- Parasuraman S
  
  July 31, 2022 at 7:46 am
  
  Since both the screens are showing white, it is assumed that the standby on and backlight is ok. In most of the cases, this is controlled by the uController. So, just check whether the TV/The other video player are responding to commands from key or remote. If they are, the problem is only in the Video input, which probably is due to shorting of the protection diode. If not the video input processing stage such as an IC could be bad. Anyhow, please don't give up. Find out the culprit and report! We too are curious to know the reasons for such failure. Similarly, also please check the output from the DVD player as well and let us know!
  
  Likes(1)Dislikes(0)
  
  Reply
Yogesh Panchal

July 30, 2022 at 11:09 pm

1. First Identify faulty / suspected part (DVD or TV) by segregating one by one.
2. Test the TV on some working video source.
3. Try by giving external Power source.
4. Clean the Main Board using Thinner /IPA.
5. Check if some Component is over heating on suspected unit.

Likes(2)Dislikes(0)

Reply
Imoudu.O

August 2, 2022 at 3:59 am

Yogest.P
Hi,thanks for your suggestions, I will try out all suggestions in due time.For now,since I need a tv for my operation urgently,I remove the screen from the affected Sony and transfer it to another device and it came out fine.Later in the month I will look to the 32" tv and the lg DVD, and will write an article to my findings.Have a nice day.

Likes(1)Dislikes(0)

Reply
- Parasuraman S
  
  August 2, 2022 at 8:12 pm
  
  We eagerly look forward to!
  
  Likes(0)Dislikes(0)
  
  Reply