Components Found Rusted, Corroded And Fungus Attacked In LG LED TV MODEL 32LK311-TB
This TV belonged to the hospital where I worked and was brought to me mentioning that it was not being used for a prolonged time and was found dead when switched on. I opened the TV and cleaned the inside thoroughly. As it was used in an AC Room, there was not much dust inside. This was a TV with LCD backlight.
When I looked at the power supply, I was shocked to see the amount of rust, corrosions and fungus formations on many components!
First I cleaned the PCB thoroughly using IPA and brushed it very well to remove the fungi. Then removed the rusted components; i.e., Three 817 Optos, two 102K/1KV Caps, one jumper wire, which I did by desoldering the legs which could be removed thus, and pulling the other rusted sides. As we all know, any rusted joint cannot be desoldered as the lead content would have got lost and the iron part got hardened like cast iron. First I applied drops of WD40 on such rusted blocked holes. Then used my hand drill and used a very thin bit and drilled such holes after waiting for some time for the WD40 to penetrate. With constant working with this method, I was able to open the blocked holes, without causing any damage to the tracks. Let us have a look at it:
Then soldered the new 817s, jumper wire, two caps etc. and thoroughly cleaned the PCB once again using IPA. Then when I applied the power through a series bulb, I could get the outputs indicated on the board, which meant that PS was back to shape.
Then reconnected the boards and applied power. It was getting on and then fed a Video signal. Following was the result:
I am giving below the pictures of the PS boards and inside of the TV before I did the replacements, just for those who want to have a look:
All this work took many hours as it involved intricacy and precision and I had to be slow and steady. After testing the TV for around 9 hours, I closed the cover and delivered it to the hospital on my visit.
Mission accomplished with vigor and satisfaction shook off all the dust of rust before entering its haven! (LOL)
This article was prepared for you by Parasuraman Subramanian from India. He is 74 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 article on Found Battery Acid Spewed All Around The Inside Of PHILIPS Radio RL384/40
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Waleed Rishmawi
August 31, 2024 at 5:06 pm
Wow, a lot of work involved but you did it nicely and professionally. Thanks for sharing and have a blessed day
Parasuraman S
August 31, 2024 at 8:11 pm
Many thanks, dear friend!
Albert van Bemmelen
August 31, 2024 at 7:31 pm
As always good work Parasuraman! At least you won't find any rats or those other short circuiting pests in Hospital TV's!
Parasuraman S
August 31, 2024 at 8:12 pm
Many thanks for your expert valuable comments, dear Albert! Yes, such rodent damages are a rarety.
Mark J
September 1, 2024 at 12:01 am
Parasuraman well done. Thank you for sharing.
Parasuraman S
September 2, 2024 at 8:19 pm
Thanks!
Jim
September 1, 2024 at 12:48 am
Great Job! .. most people do not understand all the time and patience and knowledge it takes to do a complete repair, all they can say is wow, what do you charge per hour. So glad you saved another unit!
Parasuraman S
September 2, 2024 at 8:20 pm
I have no specific charge. There is a general guidelines for us to charge by the Association. We follow that, as it is reasonable.
Imoudu.O
September 1, 2024 at 10:28 pm
Repairing psb can be interesting with necessary tools at hand, thanks for sharing sir
Parasuraman S
September 2, 2024 at 8:21 pm
Yes, dear! I love handling power supplies! Many thanks!
Henrique J. G. Ulbrich
September 1, 2024 at 11:45 pm
Excellent, Parasuraman. Thanks for sharing.
Interestingly, only the power supply was attacked. Everything else was clean. Do you have any idea why this happened?
Parasuraman S
September 2, 2024 at 8:24 pm
Power Supply board has a lot of open jumpers and components with spaces in between, which can cause fungi growth due to condensation, especially in an AC Room which gets switched on and off quite often for a long period. The mother board is thickly populated and has a varnish coat on it protecting it from weather conditions. Many thanks for your keen observation and query!
Amir
September 3, 2024 at 5:25 am
Good job! Shows how much hard work was done to repair the TV.
Parasuraman S
September 3, 2024 at 9:47 am
When we enjoy our work or what we do, the hard part melts and becomes soft! It is our mindset that matters mostly! Thanks for your comments!
Yogesh Panchal
September 5, 2024 at 2:48 pm
Good Job Sir,
These type of Rust /Oxidation is common in high humid areas Like AC room,near Creek & sea area. using Aerol Silicone Conformal Coating Spray is good idea for protecting circuit from dust & rust.
Parasuraman S
September 5, 2024 at 11:55 pm
I have bought it later for future use. Many thanks for your expert advice!