471k MOV Cracked In LED TV Repaired

 

 

 

 

 

 

 

 

 

 

This Haier LED TV  with the model of  LE22C430V was brought to me with a complaint that the customer heard a loud ‘Tick’ noise, as soon as it was switched on and it became dead. I opened the TV and did general cleaning. Removed the single board, which housed the power supply and other functions. Found the Fuse was blown. So removed it.

This is a cylindrical fuse in plastic body. Noticed black marks on the side of a rectangular filter capacitor, and found 471K MOV (Metal Oxide Varistor) cracked. Since this MOV was under the heat sink of Mosftet, I had to remove it from the board to take out the burnt MOV. Luckily, the markings were intact on the other side.

Cleaned the dark spots. Checked mosfet using Peak Atlas and found it to be ok. Put back the Mosfet.  Checked for any other component failure in the power supply section. Could not find any. Since ESR checking of all electrolytic capacitors were also showed normal reading, connected a series bulb in place of the fuse and switched on.

Checked and found 12V was coming. Did not connect the panel at this stage. Since getting replacement of Fuse and MOV of this type and value was difficult, I connected an MOV that I had, which read CVR 275/07. For the fuse, I slid a 3.15/250V fuse in a sleeve, and soldered leads on both sides for placing it horizontally.

Fixed the MOV at the rear of the Board, instead of under the sink of Mosfet, for easy accessibility and to avoid removing the Mosfet again, in case of need. Fixed the Fuse in its place.

Connected the panel to the clip-on connector and slid the strip wire to the LED back light, AC in connector and speaker connectors to their locations on the board, applied 230V AC in through a series bulb. The TV showed no signal, an indication that all was well with the TV. Connected a Video input and checked. The picture was superb!

Fixed the front cover. In this TV, we have to remove the rear screws, remove the front frame, disconnect the connections to the panel and remove the panel, to access the board, as it is fixed on the rear cover. Then we have to remove the two screws of the board and disconnect other connectors to take out the board. You can also have a look at the PWM IC used, snap of which I took when I removed the Mosfet. It is hidden under the heat sink.      

Tested the TV for more than one hour and found it to be working well.

Another job completed satisfactorily.

This article was prepared for you by Parasuraman Subramanian from India. He is 68 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 repair article below:

https://jestineyong.com/servicing-e-cook-induction-cooker-model-us2k/

 

19 Comments

1. 

   Suranga Electronics

   September 15, 2017 at 10:12 pm

   Mr Parasuraman,

   Very good repair and I like this and i have done this type of job before.

   Likes(2)Dislikes(0)

   Reply
2. 

   George Greenfield

   September 15, 2017 at 10:30 pm

   I have done a similar repair as well. Learned the "light bulb" trick early on in my career.
   Great work !

   George

   Likes(2)Dislikes(0)

   Reply
3. 

   Robert Calk

   September 16, 2017 at 12:22 am

   Good job, Parasuraman.

   Likes(1)Dislikes(0)

   Reply
4. 

   Mihai

   September 16, 2017 at 1:11 am

   Thanks for sharing !

   Likes(1)Dislikes(0)

   Reply
5. 

   Mukhtar Dange

   September 16, 2017 at 6:50 am

   Thanks for sharing

   Likes(1)Dislikes(0)

   Reply
6. 

   Albert

   September 16, 2017 at 10:47 am

   Well done job Parasuraman and great photo's. Everytime I see Sherlock Holmes appear I know it must be another great TV/monitor repair of yours. (Sherlock playing from DVD). Replacing the MOV by the right type indeed must be harder to find compared to replacing bad e-caps. And it is not often that all capacitors were within spec. Thanks for the article.

   Likes(1)Dislikes(0)

   Reply
   • 

     Parasuraman

     September 17, 2017 at 10:18 am

     It is not from DVD! It is from a USB player, which I bought for such proposes! Sherlock Holmes films are superb and any number of repetitive viewing only enables more and more enjoyment and more and more understanding of minute details which we would have overlooked!

     Likes(1)Dislikes(0)

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     • 

       Albert

       September 18, 2017 at 9:50 am

       I understand and totally agree with you Parasuraman! Most BBC series indeed are great to watch! I enjoyed watching Monarch of the Glen, Luther, All Creatures great and small (James harriot) and I like the details and the suspense in series as Father Brown, and other BBC detectives. But the American legal comedy-drama television serie Ally McBeal made me laugh to tears like no other one did! Cheers!

       Likes(3)Dislikes(0)

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       • 

         Robert Calk

         September 19, 2017 at 2:43 pm

         I like BBC shows as well and love British comedy. I haven't watched Ally McBeal yet.

         Likes(1)Dislikes(0)

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         • 

           Albert

           September 20, 2017 at 4:53 pm

           Especially the first seasons of Ally were great Robert!
           The last season(s) were a bit less enjoyable but the surprise was the Australian "Dame Edna" who joined the cast of Ally McBeal. (I was very fortuned to be able to buy the complete DVD collection box with all Seasons for only 15 euro!).

           Likes(1)Dislikes(0)

           Reply
7. 

   Lee

   September 16, 2017 at 6:52 pm

   As usual an excellent repair from Parasuraman.

   Likes(1)Dislikes(0)

   Reply
8. 

   Michael

   September 17, 2017 at 5:33 am

   Wonderful repair article Sir...i get quite inspired by reading the repair articles,why is it sometimes so difficult to find some smd devices??

   Likes(1)Dislikes(0)

   Reply
   • 

     Parasuraman

     September 17, 2017 at 10:12 am

     Business people lack service mind nowadays! They want maximum profit from large value items, which is not possible from these tiny and cheap SMD devices! Storing and retrieving is a time consuming and intricate! So on.......

     Likes(2)Dislikes(0)

     Reply
9. 

   Yogesh Panchal

   September 18, 2017 at 10:29 pm

   Good job! Sir

   Likes(1)Dislikes(0)

   Reply
10. 

    Humberto

    September 19, 2017 at 12:15 pm

    Thanks Parasuraman for sharing your experiences.

    Likes(1)Dislikes(0)

    Reply
11. 

    teddux

    October 31, 2017 at 1:31 am

    470 pico Farad Capacitor or MOV?
    Sure looks like one I just replaced on my 25+ year-old Samsung T.V.

    Likes(1)Dislikes(0)

    Reply
12. 

    Ulises Aguilar Pazzani

    December 15, 2017 at 11:25 am

    MR Parasumara, in did grate fix Sir

    Likes(1)Dislikes(0)

    Reply
13. 

    Ulises Aguilar Pazzani

    December 29, 2017 at 11:55 am

    Mr Parasuraman Have a grate Christmas and happy new Year Sir
    You are a professional tech

    Likes(1)Dislikes(0)

    Reply
14. 

    Kevinskie

    December 30, 2018 at 1:45 pm

    Good job

    Likes(0)Dislikes(0)

    Reply

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