Shorted LED Driver Mosfet In Hisense LED TV Repaired
Customer sent in this 24″ Hisense LED TV with the complaint of front Red LED light blinking. Red LED light blinking usually is due to problem in the mainboard (secondary side area ) or even in the power supply unit itself.
When I checked on the power supply output voltages, I found that the voltages fluctuated. It can be the problem in the power supply itself or something shorted in the mainboard also can cause the output to fluctuate.
This power supply has a built in LED driver circuit and when I flipped over the board, I found some of the section were affected-see the photo.
It does not look like electrolyte from electrolytic capacitor. Probably due to water entered (probably cola) and short circuit the board.
After cleaning the board with IPA, I checked on the LED driver Mosfet. It was found to be shorted-see the photo below:
Checking on other corresponding components did not find any other shorted parts so I took out another working Mosfet from a junk LED TV and fixed in and powered it up.
There was no more LED blinking and the Hisense logo immediately appeared in the screen-see photos below:
Conclusion- Assuming if the output voltages from the power are good and the power Red LED light still blinks this could means one of the memory ICs data could have corrupted. Of course you need to make sure that the memory ICs are receiving good DC supply voltages. For your information Damon Morrow just launched his latest ebook “Secret LED TV Solutions Volume 1 and you can check it out 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/unbelievable-shorted-e-cap-in-sony-dvd-hi-fi/
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Parasuraman S
February 19, 2019 at 10:18 pm
Very brief, but informative and straightforward professional trouble shooting! Excellent!
Albert van Bemmelen
February 20, 2019 at 1:29 am
Indeed fixing modern television sets is close to impossible without the much needed information from good ebooks like those from Damon and Kent. Especially the many extra bonus download files that Kent always includes with his books are much needed. The service schematics and the detailed information on the many existing systems are greatly appreciated! Sadly they still didn't help me to fix most modern European LCD televisions. And the bad quality and poor lifespan of most backlight LED's today doesn't seem to make repair any easier. Like finding the right replacement parts!
Robert Calk Jr.
February 20, 2019 at 1:45 pm
Hi Albert. My LED TV is six years old and working great! And it is on 10 - 15 hours every day! I think that most of the time when people think they have bad LED's what they really have is bad solder joints in the LED's. That is what I found wrong with my TV besides the bad contact in a LED Strip coupler. LED's are more robust than they get credit for.
Albert van Bemmelen
February 20, 2019 at 3:23 pm
Robert, your LED TV is almost brandnew compared to the mostly non LED TV's that I tried to fix! And you were very lucky you could buy the right service manual for your device. In most of my repair cases I had nothing to go on at all! Like in certain types of Samsung 42 inch TV's that had no manual at all and were badly reviewed on repair forums by other owners too! A friend of mine had his Samsung TV fixed twice in Warranty time on Backlight problems. And the third time, just after the Warranty time expired, he gave up on that bad model TV. And I therefore also had asked the ebook repair guys Damon and Kent if they knew anything about that particular European Samsung model but they sadly couldn't give any useful information either. Why the TV probably ended being used for scrap parts by its owner.
Albert van Bemmelen
February 21, 2019 at 12:51 am
You were very lucky you only had bad solder joints, Robert. The problem begins when you need to replace those bad LED's. And finding the right ones. Because it very often are blackened burned failing LED's. Sometimes even the new ones fail after a few days.
Robert Calk Jr.
February 21, 2019 at 3:47 pm
Yeah, it is always better if we can get a manual. But anytime people have a problem with a LED, they should always trying reflowing the solder first before assuming that the LED is bad.
mahmoud-tajpour
February 20, 2019 at 3:12 am
Hi dear Bandara thanks for the best repair it was very nice.
Devon Wilson
February 20, 2019 at 6:18 am
Great job. Keep up the good work. Be blessed.
Lior
February 20, 2019 at 7:41 pm
Nice article,
I have an hisense 32" led which stuck on standby, the mainboard& psu is on one board how can i repair it\ which psu\ mainboard components should I check?
Robert Calk Jr.
February 21, 2019 at 12:41 am
Good job, Suranga.
diego sarmiento
February 21, 2019 at 3:36 am
please ref mosfet shorted service manual this tv hisense thank you
Humberto
February 27, 2019 at 1:29 am
Another device saved from the dump.
Hendrick
April 28, 2019 at 1:16 am
Hi. I have a hisense LEDN50K20DGP. The backlights went off when we had a power failure at home. The TV has sound but no picture. When doing trouble shooting it came down to 1 led backlight being dead on the led strip. A friend took 1 led from another strip and soldered it on. Now the backlbacklight only come on when i use a wire on the previously dead led from positive to negative. Could he have soldered the led wrong way around?
abdi
October 5, 2021 at 1:32 am
Hi! bro, I had 24 inch hisense led TV, on one day morning I went to my tv to open it, after I powered it on at the back of my I see some some smokes and noises, as I think the circuit in the board is shoted, due to insects entering inside the cover. on the power supply board there is black spot on the board. still my tv won't working there is no LED light and the screen is black. how to resolve it?
ray
October 12, 2022 at 6:04 pm
Hi, i received a 75inch NIKAI TV that was in good operation but suddenly get water-spilled due to heavy rainfall and intrusion that went inside the TV and shorted it out.
Aftermath, busted fuse and 2 MOSFETS 65R600Q T0-252. I was trying to find an alternative because it is hard to source out this part.
Hope you can share your ideas.
ray
October 27, 2022 at 3:18 pm
WOW i fixed a NIKAI 75inch TV that was spilled with rain water during heavy rainfall. NO Power, shorted and found 2 mosfets defective.
Replaced 2 MOSFETS 65R600Q and 1 fuse. Very happy for this guide.