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Servicing CRT TV Mainboard With China Kit

By Jestine Yong on November 3, 2017

This is a JVC CRT TV, which was repaired by me in October, 2014 by replacing the main board with China Kit, as the Main Board became beyond repair due to lightning damages. After that, this had visited me in July 2016, with the complaint of arcing at anode, which was cleaned by me and given back. This CRT TV was brought to me again recently with the same complaint of arcing. Since Kerala has more monsoons, collecting moisture around the anode area is very common, especially when customers keep the TV near windows.

The customer brought the set after taking a prior appointment so that he could help me transfer the TV to work table after cleaning, due to my personal restrictions in carrying heavy things around, after recovery from a lumbar sprain. I noticed that the wire connecting to CRT anode was punctured. This is what will happen, if the customers continue to use the TV in spite of hearing arcing noises and disturbances in the picture. There was fungus growth on the other two wires as well, that go to the CRT PCB.

As the puncture was a little below the cap, I had no alternative but to suggest a replacement of the LOT (FBT), which the customer agreed. You can see its number in the next picture above. I also noticed that the PTC was broken and there were dark spots on the board near one capacitor and another resistor, that are connected between SMPS hot ground and cold ground. Please see the next pictures above.

Removed the FBT and replaced it with an exactly matching new one. Looked for and rectified a few dry joints in the board. Checked ESR of all capacitors and replaced just one 10mfd/250V located in the high voltage output area of the FBT. Replaced the capacitor and resistor, which showed signs of strain, as mentioned earlier.

Fit the board on the TV and checked and found it to be working.

I was happy on two counts; I could continue my favorite servicing on CRT TVs, and another that the customer was ready to render aid in carrying this TV around. In fact, I am thankful to him for this gesture. After this, I had undertaken service of two more CRT TVs, with the same type of gestures from the customers. My gratitude to all those who come to this extent in getting their sets serviced by me, in spite of the fact that there are many technicians around this place, who render home service! It is always a great satisfaction and encouragement when we know customers do recognize quality in service, and not just care for money and convenience!

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-audiosource-amplifier/

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Television repair

11 Comments

Anwar Shiekh

November 3, 2017 at 10:04 am

I don't know what the cost of electricity is out there, but I would be reluctant to fix a CRT unit knowing how expensive they are to run compared to an LCD TV

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- Yogesh Panchal
  
  November 11, 2017 at 12:25 am
  
  Anwar shiekh,
  
  In LCD/LED you have to pay a premium cost one time (Short Life at high Repair cost). and for the CRT it is like part payment(long life with low Repair cost).
  
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Mark

November 3, 2017 at 10:57 am

Hey Parasuraman,

Another excellent repair!
Part of the work satisfaction is when customers show real appreciation for the hard work that you do.

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Robert Calk

November 3, 2017 at 2:39 pm

Good job, Parasuraman. A good reputation is more valuable than cheap prices.

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Albert van Bemmelen

November 3, 2017 at 4:19 pm

Although LCD TVs are replacing all old crt sets and the latter are not even made anymore it is remarkable you were even able to fix an old crt model that already has been repaired more than twice over the years. It again proves that overall old crt sets have a longer lifespan than LCD screens do. Especially when you take them in your capable care! And I question if the todays larger LCD tv sets are that much more economical on cost of electricity wise compared to the smaller crt sets. Knowing that my old 39 inch Samsung LCD tv consumes about 140 Watts at its highest setting! Which is about twice that of my old Sony triniton portable (20KG!) CTV. Thanks for another excellent repair Parasuraman!

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R Murali

November 3, 2017 at 9:40 pm

I am very fond of reading your articles.Thank You sir for sharing your technical skills..

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Sanju

November 4, 2017 at 9:12 am

Excellent work sir. Also I'm proud of u. I'm from idukki, kerala. Always I'm searching for ur articles.

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shivakumar

November 4, 2017 at 3:28 pm

Dear Sir,

Thanks for your useful article. your article is step by step very easy to learn for beginners like me.

thanks with regards
shiva
Bangalore.

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Venugopal

November 4, 2017 at 5:59 pm

Clean around the crt anode with clean petrol ...then apply a coating of Red Rtv around the anode button.. (available in your place,I m also from Kerala)then connect the new eht transformer.... It will never arc again...also ask the customer to place the TV away from window.

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- Parasuraman S
  
  November 7, 2017 at 1:25 pm
  
  Thanks. I have done this to many CRT TVs. But the RTV itself can cause problems; that is the kind of quality we get from market. Moreover, that too collects carbon dust deposit and then moisture, which will cause arcing again! I had got one CRT TV with this coating, but with a crack of tube at the anode connector! So, I use IPA and clean the part thoroughly, and wipe it off. But I apply a type of red slight pink colour wax around (available as CRT Arc preventive or something, and clean it off again. Because this wax will attract and store carbon.
  
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Yogesh Panchal

November 11, 2017 at 12:26 am

Good job! Sir.

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