Pincushion Problem In CRT TV Repaired

By on July 3, 2017
singer crt tv pincushion out repaired

 

 

 

 

 

 

 

 

 

crt tv pincushion problem

Customer sent in this Singer CRT TV with the complaint of pincushion out. This means that the display at the right and left side will curve inward as seen from the top and bottom photos.




 

There are usually few common causes to this problem such as:

  1. Low B+ voltage to the Flyback transformer
  2. Shorted modulation diode
  3. Shorted pincushion transistor
  4. Open resistor at surrounding area of pincushion transistor
  5. No control signal to the base of pincushion transistor

singer crt tv pincushion out

However, in my case is pretty straight forward because I saw a bulged e-cap (1000uf 35 volt) at the horizontal output area-see the photo below:

bad capacitor cause pincushion problem

Upon further inspection, I found a dry joint in the diode’s leg that is located at corresponding circuit. When i checked the diode with my multimeter I found that the diode was shorted. Checking it off board also produced the same result.

shorted diode in crt tv

bad modulation diode in crt tv

I did checked on other components as well that is related to the pincushion circuit but all seems to be good. So, just by replacing only the two components brought the TV back to life again .

picushion problem in crt tv

crt tv repair pincusion

how to repair singer crt tv

If you want to be good in CRT TV repair you can check out Humphrey’s ebook in CRT TV repair. See you again in the next article.

suranga

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




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

http://jestineyong.com/how-to-repair-no-sound-problem-in-sansui-hi-fi/

 

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12 Comments

  1. Parasuraman S

    July 3, 2017 at 10:55 am

    Excellent! Expertise in action!

    Likes(5)Dislikes(0)
  2. Yogesh Panchal

    July 3, 2017 at 4:05 pm

    Good job!Suranga.

    Likes(3)Dislikes(0)
  3. Tariq

    July 3, 2017 at 4:39 pm

    Thank you. But I'd need further information about the pincushin transistor like location and job.

    Tariq

    Yemen

    Likes(3)Dislikes(1)
  4. Mark

    July 3, 2017 at 7:43 pm

    Well done Suranga!

    Likes(2)Dislikes(0)
  5. ANGELO

    July 3, 2017 at 11:30 pm

    THANK YOU SIR "SURANGA"
    COULD U OR ANYONE PLZZZ PROVIDE ME SOME PICS OF PINCUSHION AREA?
    THANKS IN ADVANCE...

    Likes(2)Dislikes(0)
  6. Jai Etwaroo

    July 4, 2017 at 4:35 am

    Good job Suranga

    Likes(1)Dislikes(0)
  7. Albert

    July 4, 2017 at 12:17 pm

    As soon as I read 'pincushion' I knew it had to do something with e-caps. Good pro job Suranga.

    Likes(3)Dislikes(0)
  8. Humberto

    July 4, 2017 at 12:33 pm

    Excellent Suranga.

    Likes(2)Dislikes(0)
  9. Robert Calk

    July 6, 2017 at 11:48 pm

    Good job, Suranga.

    Likes(0)Dislikes(0)
  10. mahmoud_tajpour

    July 9, 2017 at 5:01 am

    Thanks Suranga best job well done.

    Likes(0)Dislikes(0)
  11. parashu ram singh

    July 11, 2017 at 1:16 pm

    nice video and got knowledge from given fault and sir
    you are providing me outstanding information and good too.
    thanks for cooperation in future.

    Likes(0)Dislikes(0)
  12. Calum

    September 4, 2017 at 9:57 am

    good job bro

    Likes(0)Dislikes(0)

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