Hard Lesson Learned In This HAIER LED TV Model LE22B600
This LED TV has visited my service workshop in September, 2022 and I request you to see the following link as I am not repeating basic images of the TV:
https://jestineyong.com/sudden-power-surge-blew-smps-in-two-haier-led-tvs-model-le22b600/
Same TV visited me in May, 2024 for not getting released from standby mode, which I have covered in a different article as problem was of software.
This time (in July, 2024) the problem was set gets on but suddenly goes to standby mode. After opening the set and looking in both power supply and mother board, for any bulgy capacitors or other power related issues, I removed the speaker connector on an instinct from previous experiences, and applied power to find that the TV was working very well then. It showed that the speaker was the problem. I fetched equivalent speakers from the market and replaced it and noticed that only one channel was working and the other was dead. Continuity of speaker wire was ok and the capacitor connected to it was also ok. In order to know the audio IC number, I desoldered the heat zinc tabs. Let us have a look at the pictures:
I downloaded the datasheet of TDA1517P and looked at the pin configuration:
Checked the VCC at pin 7 and found it to be ok at 10.45V. This IC works from a minimum of 6V to maximum of 18V. Typical power supply is 14.4V. Then I used my signal injector and applied signal at pin 1 & 9. The outputs were ok, indicating that the audio IC was ok. Then checked the headphone socket as any problem there might cause output problems. It was ok. The next step is to see where the inputs are coming to the IC.
This aroused the Sherlock Holms in me and I geared up well with my lens to find the culprit. As there was no pre-amp stage, I assumed it might be coming from the main IC, as nowadays, almost all TVs have such one Chip solution for all functions. I looked at the IC number and downloaded the pin configuration image after a lot of search in the web. No IC datasheet was available, as expected.
I checked the input components of the channel which had no output and found these to be ok, when compared to the other working channel. The datasheet showed pins 46 to 49 were the audio outs. I injected signal at the outer side of the coupling SMD capacitor and got clear audio on both the speakers. So, I suspected some malfunction of software or the IC itself, though there were no symptoms as an indication. Then I posted this problem in my technical group to check whether anyone else has faced this problem and what was the solution they found. Though a few answered, the one question posed by an expert technician hit me like lightning! The question was whether I checked the balance control in audio user setting. Then I quickly pressed the settings, clicked on sound and found that the balance was extremely at the right side and not in centre. Sound was ok on both channels when I slid the cursor to the middle.
Some user has changed the normally unused setting or some child has played on it. But look at me! I sat there like a stupid fool! In spite of years of experience, I overlooked the basic step and paid a heavy price of precious time and energy! A hard lesson was learnt. I re-fixed the heat zinc and the mother board back in its place. Allowed the TV to run for several hours, before closing the back cover. I delivered the TV to the hospital during my scheduled visit to close the curtain on this elongated short story! Intense satisfaction gained entry to the collection bag and I gained more knowledge from my hunting searches.
This article was prepared for you by Parasuraman Subramanian from India. He is 74 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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You may check on his previous article on Futile Attempt To Revive A Micro Controller In YAMAHA Tape Deck Model K-340
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Albert van Bemmelen
September 14, 2024 at 7:35 pm
If we cannot find any other reason for a problem it often leads us to the obvious conclusion that we overlooked the fact that nothing was defect! Like in this example when it only was a wrong setting. And that happens to the best of us!
Parasuraman S
September 15, 2024 at 4:03 pm
Many thanks for your expert and valuable comments, dear Albert!
Anthony Paterson
September 14, 2024 at 8:30 pm
Perfect example for putting all 'controls' to their mid-position.
Parasuraman S
September 15, 2024 at 4:04 pm
Exactly! We need pruning to grow up vigourously further! Thanks for your comments!
Henrique J. G. Ulbrich
September 14, 2024 at 10:56 pm
Greetings, Parasuraman. Another well-succeeded maintenance job. Therefore, a question remained: How could a balance control position cause a standby mode to be achieved?
Parasuraman S
September 15, 2024 at 4:06 pm
Balance control problem did not cause standby. Looks like you have not gone through my article fully. Standby was caused by problems with speakers, which were replaced.
Waleed Rishmawi
September 14, 2024 at 11:19 pm
I had that issue before and it took me about two to three days to figure out that the sound balance was off and how stupid I felt but a lesson well learned. Thanks for sharing and someone said life is a big school that we learn from.. have a blessed day.
Parasuraman S
September 15, 2024 at 4:07 pm
Defintely, dear friend! Once in a while we need to get reset!
Tyrone
September 15, 2024 at 1:17 am
Hi friend as a hobbyist I would never have thought of looking at that. Thanks for sharing your experience
Parasuraman S
September 15, 2024 at 4:07 pm
Thanks for your comments!
Maarten Dekkers
September 15, 2024 at 1:38 am
Dear Parasuraman, thanks for another good repair story! It brought back memories from the time I was in personal computer repair. We always did do a "BIOS reset to defaults" after confirming the users complaint. Then started the diagnosis... Not sure if there is such a method for modern TV and audio sets?!
Parasuraman S
September 15, 2024 at 4:08 pm
There indeed is a provision for resetting. But that would reset customer's settings too. So, we do it only if and when found necessary!
Mark J
September 15, 2024 at 3:26 am
Parasuraman Don't worry about it. Every technician has made that mistake at one time or another. Over look something simple. Well done on the repair.
Parasuraman S
September 15, 2024 at 4:09 pm
Thanks for your consoling comments, dear Mark!
Yogesh Panchal
September 15, 2024 at 7:53 pm
Good Job! Sir,
Good inspection approach, this problem solving practice keeps our skills Upgrades and maintain to follow the inspection process. Normally our primary approach to inspection as a technician is hardware, but now a days every technical device is controlled by software.
Parasuraman S
September 15, 2024 at 10:32 pm
Yes, advancement in technology has passed on most of the functions to software. Thanks, dear Yogesh!
Andre Gopee
September 16, 2024 at 10:29 pm
As a technician with many years of experience, I make lots of silly stupid mistakes like those. But without mistakes we wont learn and I am sure next time around you'll be sure to check those common thing before hand. Nice article BTW.
Parasuraman S
September 17, 2024 at 11:04 am
Yes, sure I will remember and that is why I gave the title 'hard lesson learned'! Thanks for your comments and compassion!