Singer 32″ Skyworth LED TV With Dim Display Repair

By on November 16, 2015



singer led tv repair

 

 

 

 

 

 

 

 

 
Singer 32" Skyworth LED TV With Dim Display Repair

The complaint of this Singer Skyworth 32″ LED TV was no display but when I used a torch light to shine at the screen I could see dim display picture. This means the actual fault was dim display and not no display.

The cause of this problem was the LED backlight circuit not functioning-see the photo below:

 

led tv repair

As usual, in order to repair any electronic equipment one has to open up the cover. In this LED TV, it was easy to remove the screws and the cover can be lifted out easily. Once the cover was removed, I could see the mainboard and the power supply/ LED driver board. The LED controller board was located at the top part (long horizontal circuit board).

led tv repairing

The first thing I do was to check on the output voltage to the LED backlights.

check led tv voltage

From the board marking of the LED backlight connector, it stated 60 vdc which means 60 dc volt is required to light up the LED backlight. However, from the measurement I’ve got only 26.6 volt which is abnormal.

checking led tv voltage

So, I proceeded to trace the 60 volts line from the back of the connector and the line brought me to a circuit that has two big SMD diodes-see the photo below:

shorted diode in led tv

I took out both diodes to check (checking diodes off board is much accurate than to check it on board) and found one was shorted and the other one good-see the two photos below:

diode shorted reading

good diode reading

Since I do not have this kind of diode, I used a axial lead fast recovery diode with 3 ampere as replacement. I had to cut away the long lead and slowly position the diode onto the original location

diode replacement

After the installation of the diode, I powered On the LED TV and as expected, I’ve got 62.7 volt at the LED backlight connector.

32' led tv repair

The below two pictures is what I saw when everything were put back. Another job done and made some profits from this repair. If you wish to learn how to repair LED TV you can check out Kent’s and Damon’s ebook.

working led tv

singer led tv repaired

suranga

This article was prepared for you by Suranga Bandara who owns an Electronics shop in Anuradapura, Sri Lanka.

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Note: You may check out his previous repair article in the below link:

http://www.jestineyong.com/lg-slim-tv-with-one-horizontal-line-solved/

 

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15 Comments

  1. Yogesh Panchal

    November 16, 2015 at 4:24 pm

    Good Job! Suranga and thanks for sharing.

    Likes(6)Dislikes(0)
  2. Parasuraman S

    November 16, 2015 at 5:27 pm

    Good job! Your ability to get to the root cause of the problem is laudable! Please keep sharing your valuable experiences! All the best!

    Likes(4)Dislikes(0)
  3. Gerald Millward

    November 16, 2015 at 6:53 pm

    I only repair computers, but inverter failure is also a common fault in computer displays, with this type of diagnosis and repair for desktop monitors, but usually just a case of replacing the small inverter unit in laptops. Innovative use of a standard diode here Suranga! SMD diodes of this type are common in laptop motherboards - but rarely of such high voltage - pity!

    Likes(4)Dislikes(1)
  4. Albert van Bemmelen

    November 16, 2015 at 7:41 pm

    Nice repair Mr.Suranga. I tried to read the SMD code from the Diodes
    on the Photos you took, but that was not possible. Since you didn't
    mention this. But I understand that they both were connected in
    parallel. So the max current to the Backlight Leds would be tops
    about 6 Amps?

    Likes(5)Dislikes(0)
  5. Robert Calk

    November 16, 2015 at 7:49 pm

    Good job, Suranga! I love reading articles where you do some good improvising to get the job done. It also saves your customer some
    money!

    Likes(3)Dislikes(0)
  6. jose walter tenorio

    November 16, 2015 at 10:18 pm

    Good morning, good explanation , keep sharing , keep the peace of God .

    Likes(4)Dislikes(0)
  7. beh

    November 17, 2015 at 1:59 am

    Thanks for sharing and keep it up SURANGA.

    Likes(2)Dislikes(0)
  8. H

    November 18, 2015 at 1:40 am

    Great repair Suranga. I've substituted SMD Diodes for normal Diodes (with the same features or similars)sometimes. Keep up

    Likes(1)Dislikes(0)
  9. Hicham

    November 18, 2015 at 7:03 pm

    Thanks Mr SURANGA for this sharing, keep it up.

    Likes(0)Dislikes(0)
  10. joseph

    November 19, 2015 at 1:32 am

    Great one.

    Likes(0)Dislikes(0)
  11. Mark Tembo

    November 19, 2015 at 10:39 pm

    Good initiative!

    Likes(0)Dislikes(0)
  12. Claude

    July 28, 2016 at 11:28 am

    Great !!! very good illustration. Well understood and clearly explained.
    Keep it Up. Proud of you

    Likes(0)Dislikes(0)
  13. Rafael

    November 20, 2016 at 12:03 am

    thanks for sharing.

    Likes(0)Dislikes(0)

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