Unknown Burst Component Bypassed To Restore Sound In SHARP LED TV MODEL LC-32LE341M
This TV was yet another one that I got the chance to restore at my friend’s place (Panel Bonding Expert). The TV came to his shop with the complaint that there was no sound, but picture was ok. When it was opened and checked, a component near the audio input section was burst, leaving only black marks.
There was not even a trace of it. From the print on the PCB, I guessed it could be a transistor, to sense audio input and switch it on. (Picture of this is given in the article later) In the process, I also learnt a trick from him; how to easily trace the sound input to the main IC. This TV had a single chip which handled all the functions. Have a look below:
What is the trick he used? I am sure many of you might be curious to know! Well, he powered the TV up and fed a video signal, and held the audio in through an electrolytic capacitor, on his left hand index finger. Then applied a bit of saliva on his right hand index finger and started touching the input sections from the RC socket towards the IC. At one place, the sound came, though very weak. The spot was traced so easily.
Then he applied the audio directly through the capacitor and found out that the audio worked very well, when touched at inside points of two resistors (left and right channel) that go to the IC. The sound was perfect. Why did he not use the capacitor itself to touch, might be a doubt you all may have. Touching with fingers can cover more area avoiding the need to touch each point. Then he asked me to bypass the audio input by separate hook up wires, which I did. I used his microscope to solder the wires to the two tiny SMD resistors.
The sound got restored fully once this was done. I closed the TV and transferred it to the Delivery Section of his shop.
Mission accomplished with satisfaction collected!
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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Waleed Rishmawi
December 17, 2022 at 2:43 pm
Neat trick. thanks for sharing. thanks for sharing and have a blessed day
Parasuraman S
December 17, 2022 at 4:30 pm
Many thanks for your comments!
Albert van Bemmelen
December 17, 2022 at 3:20 pm
A good test method is always the best way to fix a problem! I guess that first the audio volume settting was raised too to make sure the audio output could easily be heard.
Parasuraman S
December 17, 2022 at 4:31 pm
Yes, volume control was indeed raised before conducting the test! A keen observer! Many thanks for your comments!
Yogesh Panchal
December 17, 2022 at 4:46 pm
One more out of the box,Nice trick Sir,
Parasuraman S
December 18, 2022 at 1:47 pm
Many thanks!
Rodger Hopkins
December 20, 2022 at 12:08 pm
Nice job, as always.
Parasuraman S
December 21, 2022 at 8:56 am
Many thanks!