MBRF10200CT Dual Schottky Diode Shorted In LED TV Repaired
This Innovex 24″ LED TV came in with the complaint of no power symptom. For your information a no power symptom can be caused by either the primary or secondary side of power supply or even both sides. The first thing to check obviously is the main fuse and it was found to be good.
Since the main fuse was good so I need to power up and check on the secondary side to see if there is any DC voltage and it was totally zero volt.
Below are the photos of the power supply and main board and the photo of meter showing zero volt when checked on the secondary side.
Before I further check on other components in the power supply section, I noticed there were dry joints at the transformer pins.
I applied fresh solder to those joints and powered it up and the result was still the same.
I proceeded to check the components at the secondary side first before checking the primary side and I did not expect one of the 3 legged Schottky diode showed shorted reading on board. I took the diode out and checked it off board and it was still shorted.
The Schottky diode part number was MBRF10200CT and you can check on the next photo for the datasheet. The TV was repaired by replacing only the Schottky diode and two filter capacitors.
Please click on the above photo to read the MBRF10200CT Schottky Diode Datasheet
Conclusion- Assuming if after the replacement of the Schottky diode and still not be able to power up, guess I have to check on the primary section such as to see if there is any VCC to the Power IC, replace power IC, check power FET and etc. Actually troubleshooting Consumer electronics switch mode power supplies (SMPS) is not that difficult if you could follow Jestine Yong’s way where he had documented troubleshooting SMPS the easy ways in his ebook here.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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https://jestineyong.com/unwanted-visitor-found-in-lg-43-inch-led-tv/
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Albert van Bemmelen
November 3, 2020 at 7:32 pm
Although I never heard about this Innovex brand of TV
before it must have been a good designed model because only so few parts needed replacements. In case someone wants to buy a decent TV it would have been interesting to know what type of model it exactly was.
Ananda Athukorala
November 3, 2020 at 7:50 pm
Good article.
Parasuraman S
November 3, 2020 at 9:53 pm
Very useful and informative article! Well done!
babums
November 3, 2020 at 10:11 pm
Thanks very much for your good repair article.
Lynn Blakely
November 3, 2020 at 10:44 pm
Sir Suranga: Thanks for the excellent article, and pictures.
Waleed Rishmawi
November 4, 2020 at 5:06 pm
very common issue in this TV model especially the dry soldering joints. i have seen that so many times so far but the shorted diode, i have not seen that in this tv model. thanks for sharing and have a blessed day
Tito Kanshulu
November 4, 2020 at 10:34 pm
Very informative
Humberto
November 7, 2020 at 10:45 am
Good repair, Suranga. By the way, I had never seen that brand.
Yogesh Panchal
November 7, 2020 at 8:10 pm
Good Job! Suranga.