Hisense 50″ Smart TV Struck By Lightning Repaired
Firstly, let it be said, that as an electronics hobbyist, I am constantly learning, making mistakes, studying, making wrong diagnoses, even having many ‘slap the forehead with the palm of the hand’ moments and learning by my mistakes. Despite all of that, I thoroughly enjoy the whole experience – especially when you finally end up with a successful repair. I have many of these moments in my chosen trade – automotive, but I have over 41 years in the trade and a fair amount of experience. But when you see success in some area where you don’t have formal training, it can be a real ‘buzz’ to see something turn on and operate after you have had it apart, operating on its heart and soul.
That being said, when I successfully diagnosed and repaired this TV, with direction from Jestine’s book ‘Testing Electronic Components’ & received guidance from Jestine via Email, my confidence jumped ahead in leaps and bounds.
Just having someone confirm what you have been testing and your suspected diagnosis is a great support.
And so, the story begins…….
This Hisense 50” Smart TV had been a victim of a lightning strike. A friend of mine was asked by a customer of his to take it to landfill as he was cleaning the house for renovations. My friend thought of me and I was at the house to pick it up in a flash, bringing my treasure home – much to the disappointment of my wife. 😊
Being a 50” TV, it wouldn’t fit in my lab, so testing was done on the dinning table. My wife was suitably impressed – NOT! 😒
This TV had no standby light. Although I couldn’t find a service manual, the voltages were written on the power board and testing proved that no voltages were being supplied to the mainboard. Considering this TV had a disagreement with a lightning bolt, I decided to check the protection circuit. Surely, with thousands, possibly millions of volts surging through the TV, I would naturally expect a blown fuse, varistor, thermistor, maybe some diodes and MOSFETS to be a little worse for wear.
However, after checking these components, I was surprised that not even the fuse was blown! Further inspection showed a burnt track on the back of the board.
After cleaning up the burnt area, I made several incorrect conclusions. I naturally assumed that the inductor on the other side would be burnt out. Secondly, I thought that perhaps after bypassing this damaged track the TV might actually work! Wrong on both counts!
It is possible that this area became the weakest link during the high voltage surge & acted as a ‘spark gap’.
A wire created a bypass for the burnt-out track. Although I had tested the inductor with a multimeter, this was not the best method. So, using my Blue Ring Tester proved that the inductor was in good condition.
After this repair and test, I now had 340 volts at my main filter capacitors – that was good news!
Further inspection showed one of the two optocouplers to be shorted on the Infrared side and open on the photo transistor side. However, even with the optocoupler removed, there was still a short on the board. At first, I suspected a SMD capacitor to be faulty, but after further testing, it was found to be within specifications. Lifting one leg of the capacitor still resulted in a short in this circuit. After carefully examining the schematic, I decided to remove the IC, a NCP1271 Standby PWM Controller, to see if this had an internal short.
Success! The short had disappeared! This was evidence that the IC had shorted and damaged the optocoupler.
I have been replacing ICs for a while now, with varying success. But as they say, practice makes perfect (or workable at least..). I am currently working on a circuit tester IC with 64 legs and that has taken some patience! I also have had a digital microscope for a while but have generally used my magnifying glass light to do repairs. This time, I decided to use the microscope for this repair. It helped me make sure that I had the IC aligned and no solder bridges existed. Also, the optocoupler was replaced and all flux residue was removed. Testing the circuit again showed the short had been removed.
Now I could see a standby light when the power button was turned on.
The previously damaged TV now had all the features working. I’m sure we have all experienced the ‘buzz’ when you have repaired something you would normally consider out of your skill range. As a hobbyist, when I am able to bring a complex repair back to life, it gives me a boost to take on the next challenge.
Not only was this TV saved from landfill, but I was able to sell it quite easily. I would personally like to thank Jestine for his book, his guidance and web page where we can share our repairs, experiences and gain help when needed.
If you are interested in this repair, you can see a video on my channel following the link below:
This article was prepared for you by Mark Rabone from Australia.
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Note: You can check out his previous repair article below:
https://jestineyong.com/shark-upright-vacuum-cleaner-repaired/
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Andrew F. Ali
January 8, 2021 at 6:56 pm
Very nice work.
Mark
January 8, 2021 at 8:23 pm
Thanks Andrew - always learning
Lulamile tsoai
August 29, 2024 at 5:08 am
My DVD receiver it 302sd/sd/az is not display
Albert van Bemmelen
January 8, 2021 at 8:15 pm
Nice job Mark! I completely understand why your wife wasn't happy with the space you needed to fix this large 50 inch tv. That is also one of the reasons why I hardly fix any modern large televisions these days. I only wondered why you decided to sell it after successfully fixing it?
Mark
January 9, 2021 at 8:00 am
Hey Albert,
Thanks for your comments. Yes, I wasn't overly popular for a while.....
We have a TV already, so had no use for it & was able to sell it and use the money to buy more electronic testing equipment.
I also had an offer to repair a bigger TV, but the same issue existed.
Gassan Ali
January 8, 2021 at 8:56 pm
Nice work! I watch your youtube channel often.
Mark
January 9, 2021 at 8:01 am
Thanks Gassan Ali,
It's good to have you on board!
Humphrey Mndaka
January 8, 2021 at 10:00 pm
look good, Keep going Mark
Regards Humphrey
emmanuel mumba
January 8, 2021 at 11:05 pm
hai humphrey, just want to thank you for your you books,your simplicity has made me become a better technician than i was before, many thanks also goes to jestine for his newsletter email, website and books,
Humphrey Mndaka
January 10, 2021 at 1:36 am
Thank you Emmanuel for the kind and encouraging words.
Wishing you the best.
Regards Humphrey
Mark
January 9, 2021 at 8:03 am
Thanks Humphrey,
As Emmanuel has mentioned below, I use Jestine's books as well as yours when I do my repairs, so you should take some credit as well!
Humphrey Mndaka
January 10, 2021 at 1:45 am
Thank you Mark, love your passion in electronics.
Regards Humphrey
emmanuel mumba
January 8, 2021 at 11:06 pm
nice work and job done without fail
Mark
January 9, 2021 at 8:05 am
Hey Emmanuel,
There were many fails along the way, but I'm glad I persisted as a successful result was really rewarding.
Alena
January 8, 2021 at 11:22 pm
Hello Mark nice fix! I want to ask, in your opinion, if job of electronic technician desirable in Australia. Do many items end up in the damp like in UK or people rather fix them? Thanks
Kind Regards
Mark
January 9, 2021 at 8:14 am
Hey Alena,
I guess it is similar the world around in wealthier countries. We live in a throw away society. Some of the repairs I have done are specialist ones, such as the laser pick up on a wheel alignment machine.
As a hobbyist, I only do electronic repairs on occasion as most people simply throw appliances away because it is easier and sometimes cheaper to buy a new one. As you know, diagnosing electronic repairs takes time and people aren't willing to pay for that time if they can go to the local appliance store and purchase something that will last another 3 years. Most people tire of appliances and want the 'latest' even though the current one may be working fine.
It is so frustrating to see such waste. I have gone to the recycling depot to bring things home & repair, rather than taking 'waste' to the depot.
That's why I appreciate Jestine's site and all the help I receive from others to keep these items out of landfill.
Parasuraman S
January 9, 2021 at 12:05 am
Hi! Looks like after a long gap! Excellent article providing enough humour, though handling a 'Lightning' case! Very professional approach and solution! Well done!
Mark
January 9, 2021 at 8:17 am
Hey Parasuraman,
It has been a while in between articles.
I really enjoyed this repair and have gained so much experience, knowledge and confidence by tackling this 'beast'!
Jim Whalen
January 9, 2021 at 12:27 am
Your video was awesome.
Mark
January 9, 2021 at 8:19 am
Hey Jim,
I have 40 videos dealing on electrical/electronic repairs on my channel.
I have learned so much from others that I wanted to share with people interested in learning.
Waleed Rishmawi
January 9, 2021 at 10:57 am
Congrats on a big successful repair. Keep up the good work.
Mark
January 9, 2021 at 6:10 pm
Thanks Waleed.
Nigel
January 9, 2021 at 3:13 pm
Hi Mark, the title caught my attention for I collected a 55" Hisense smart TV last year by the side of a bin in my neighborhood and when I opened it up I found the logic board missing. I guess the owner since the power board had some faults sold off the logic board. I purchase a new logic board and replace a few caps on the power board and have myself a huge screen in my living room. One man's trash is another mans treasure.
Mark
January 9, 2021 at 6:12 pm
Well done Nigel!
You sound like a man after my own heart!
It is amazing how often things can be repaired with just a little attention.
Yogesh Panchal
January 9, 2021 at 6:26 pm
Mark!
This is self satisfying moment for every technician to those who have eager for some thing to learn.Of course if you can make money out of that..... that is an addition to our income simple calculation is that what you got from the Investment in terms of the time & Money for balancing our satisfaction and for our needs for better life.
Mark
January 9, 2021 at 6:45 pm
Hey Yogesh,
I agree, you can make some money out of the repairs, but it's the satisfaction of a successful repair that makes it rewarding.
Owais Akhter
January 10, 2021 at 6:32 am
Hi Mark, I was read your article and saw video just after reading. It was a great repair you have done. I really appreciate your effort and time for making this article and video and sharing your experience with all of us. Keep doing repair work. I really like people who fix things even for not only selling but for their own satisfaction and learning. God bless you.
Mark
January 10, 2021 at 9:30 am
Hey Owais,
I agree. I look at every faulty appliance as a challenge and a rewarding learning experience. I don't get to repair all things to completion due to my skill level, but every repair I attempt, I gain more experience and confidence, ready to tackle another repair.
Thanks for your comment.
Mihai
January 10, 2021 at 8:04 pm
Hello, Mr. Mark ,
Good job !
Thank's for sharing your experience !
Mark
January 11, 2021 at 5:36 pm
Thanks for your interest Mihai!
Niten
January 11, 2021 at 4:17 am
Hello Mark,
Great Job!
Thanks for sharing.
Mark
January 11, 2021 at 5:36 pm
Hey Niten,
I appreciate your comment - thanks!
Lynn Blakely
February 23, 2022 at 7:03 am
Mark: You found out to always check for shorts, when you found the foil had acted as a fuse. An excellent example to all that read your humorous dialogue. With good pictures.