Standby LED Blinks In Haier LED TV Repaired
The complaint of this Haier 24″ LED TV was standby LED light blinking. For your information standby LED light blinking problem can be caused by bad power supply output voltage, bad voltage regulator IC in the mainboard or firmware corrupted. If the output voltage from the power supply is unstable thus the DC supply voltage to the MCU IC and other memory ICs also become unstable eventhough there is a voltage regulator IC being used. Being said that if the fluctuation DC supply voltage is too high entering the input pin of voltage regulator IC the output would be affected as well and this will cause the MCU IC to send out a continuous signal to the power LED causing it to blink indicating error.
If the voltage regulator IC itself have problem, the output voltage can become lower than the specific/rated voltage thus the MCU IC may not even function properly causing power blink. One good example is the 1.2 volt voltage regulator IC that output 0.8 or lower voltage in one of the LED TV mainboard models causing the power LED not to light up or blinks. In the photo below, the power supply is integrated with the mainboard:
With just visual inspection there were six bulged capacitors found in the board. See the three photos below:
Once the 6 bad capacitors have been replaced the display came back and no longer have power LED blinking problem.
Conclusion- It was a simple repair. However, if no bad capacitors found then I have to use the voltage checking method to check on the voltage regulator IC output to make sure it has a correct DC output. If the DC output voltage is good then I may have to reprogram the EEPROM IC first before the MCU IC.
You can check out my previous repair article here on LCD Monitor that had no power and it was the firmware fault and got nothing to do with the power supply. I hope you got the points of what I’m trying to explain in this article. By the way you can checkout Damon’s latest 713 and 348 PDF list about problems and solutions in LED TV Repair.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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December 4, 2020 at 6:20 pm
Can I just at the quality of the repair articles technical workmanship is very low in the past 2 years.
It is always some:
- some led strip burnt out in a TV
It is the same thing over and over.
Sent from my iPhone
December 5, 2020 at 12:56 pm
Thanks for the honest feedback. For your information I have three levels of readers that read the blog posts. They are the beginners, intermediates and advanced repairers. Sometimes if the blog post is too advanced the beginners may not be able to understand it. If the blog post is about simple repair then the advanced repairers may not enjoy it. There are also readers that liked the old valve equipment repair. This is why the repair articles that I have posted is for mixed levels and not targeted to only one level. For your info also I did not post repair article only on a specific equipment ( Ex-Tv repair articles) because the theme of my website is about "Make Electronics Repair Great Again" . It means that as long as the articles is about electronics repair no matter what type of equipment, I will post it. I wish that I can please everyone and to satisfy all their needs but there is no way I can do that . I hope you can understand my situation.
By the way, probably you can consider to contribute the repair articles just like what the other authors had done as this will make the blog even better. The more contributors the more we can learn from each others.
December 4, 2020 at 6:21 pm
Well done! Thanks for sharing!
December 5, 2020 at 11:21 pm
You are right Mr Jestine.keep it up.
December 6, 2020 at 3:42 pm
Agree with you Sir, Jestine
This whole thing is about Knowledge if it works for you get it and if not leave it for other people who need it.
December 6, 2020 at 3:43 pm
December 6, 2020 at 10:46 pm
Aún el más preparado encuentra algo que aprender en tu pagina. Debemos comprender no solamente a quien sube un post, sino a todo aquel que, con diferentes niveles, aprovecha algun conocimiento ya sea nuevo o reafirmando algo que ya se tiene.
Saludos y gracias desde México y adelante!!
Even the most prepared find something to learn on your page. We must understand not only who uploads a post, but also everyone who, with different levels, takes advantage of some knowledge, whether new or reaffirming something that they already have.
Greetings and thanks from Mexico and forward!
December 10, 2020 at 3:10 am
I have a jbl subwoor model is SUB140/230
so I need one board
January 15, 2021 at 2:08 am
Well done bro