Voltage Surge Shorted Two Mosfets And Blew The Fuse In Samsung LED TV LA32D451G3
This TV was brought from my neighborhood with the complaint that it was found dead when switched on one day. After opening the back cover and subjecting it to a thorough cleaning, I looked for the problem creator in the power supply area.
There was no output, which led me to trace a blown fuse. Further checking revealed dead short of two Mosfets that drove the back light. I removed the connector of backlight and checked the LEDs using my LED tester and found it to be working.
The Mosfet number used was 5N50 (5A, 500V). I used 6N90 (6A, 900V) instead and wired it providing heat zincs and fixing it on the metal chassis. Then when I powered the board after replacing the fuse, the output was present.
Then connected the mother board and found the TV to be working well, upon which I closed the back cover and allowed the TV to be on for several hours before delivering it to the customer. Mission accomplished and satisfaction got added to the collection with pleasure!
This article was prepared for you by Parasuraman Subramanian from India. He is 72 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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Albert van Bemmelen
September 23, 2023 at 1:22 pm
You not only fixed this Samsung TV but also made an upgrade by replacing the 2 previously smaller smd mosfets by 2 bigger decently cooled mosfets too!
With also better max voltage/current specs!
Parasuraman S
September 23, 2023 at 1:44 pm
Many thanks, dear, for your expert observation and comments!
James
September 23, 2023 at 7:00 pm
Thank you parashuram sir congratulations you're experience in valve Radio system
Parasuraman S
September 23, 2023 at 11:17 pm
Many thanks, dear James!
Waleed Rishmawi
September 23, 2023 at 1:26 pm
a very good job my friend. where do you find such mosfets? if you have the link please share it. thanks and have a blessed day
Parasuraman S
September 23, 2023 at 1:44 pm
These are locally available in the electronic shops. Many thanks.
Yogesh Panchal
September 23, 2023 at 3:36 pm
Good fix! Sir
Parasuraman S
September 23, 2023 at 11:17 pm
Thanks!
Imoudu.O
September 24, 2023 at 2:18 am
It's always difficult in my area to get those small fets to purchase,I never thought a big fet can be used to replace small one, now that I know, l gonna try it some day.Thanks for sharing sir
Parasuraman S
September 24, 2023 at 12:22 pm
It's not the size what matters when we replace components. It's the specification. Many thanks for your comments!