This television came from a friend with the
complaints above, I tested it at his place and I confirmed the symptoms.
So I took it with me to the workshop and since I confirmed
the symptoms at the owners place I went straight to open the panel and accessed
the backlight and after testing with my backlight tester I did not get any
fault led and I was frustrated because I expected it to be easy fix.
I re-assembled the set and decided to do one more
observation and I therefore applied the power and to my surprise the television
was up and running.
I tested it for two hours and still the TV was okay,
then I decided to call the owner and inform him that the TV is now okay and
ready for collection.
The customer was very happy to hear the good news but
on my side I was not happy because I could not figure out if there was a bad
connection I might have fixed without me being aware or it’s an intermittent
problem with the television.
Usually I give all my customers three month guarantee
and therefore I was expecting a call back any time since for sure there is no
magic in electronics repair.
After one weeks I got a call from the same customer
and told me that the same problem is back.
I was expecting this and off I went and collected the
TV and brought it to the shop and now very determined to get the root cause of
this intermittent problem.
This time there was no taking chances and I had to do
thorough investigations and luckily I had another TV same mode and wanted to
compare the two particularly the backlights voltages.
Each strip had 8 leds.
Good TV readings voltages
Strip 1:22.2 volts
Strip 2: 22.3 volts
Strip 3: 21.9 volts
Returned back TV readings
Strip1: 22.1 volts
Strip2: 22.8
volts
Strip3: 22.0 volts
Looking at the returned television results, you can
see strip 2 figures are quite high compared to the other strips and I decided
to replace all the leds on that strip and was able to get 22.3 volts finally.
After replacing all the leds I re-assembled the
television, once again was up and running and I took it back the owner and up
to now two months later the TV is still running and no complains at all.
I think Sony televisions are very sensitive and hence
a small variation on total voltage dropped by the leds backlight can shut down
the whole television even if no led has failed.
Kindly note that in your future repairs with Sony
televisions.
Visit our Nairobi office here or Contact us on +254 733 475 040
Most appreciated, our Guru.
ReplyDeleteKind regards
Mark
Good afternoon sir, thanks for sharing. But my question is, you mean the main board was failing to start up because of the faulty LEDs?
ReplyDeleteA great article! I enjoyed reading it.
ReplyDeleteMy friend asap I will buy the pdf books
ReplyDeleteHumphrey that was very informational , thanks so much
ReplyDeleteQuestion: I wanna speed up my repairing time by buying ESR blue ring tester or any food quality meter that can easily test capacitors inside curcuit