Modification Of LED TV SMPS[ stands for switched mode power supply]
This 24 Inch LED TV
came in with the complaint of no power.
Generally no power
symptom mostly are cause by the failure in the power supply board. It can also
cause by failure of the mainboard because the power LED signal is coming from
the mainboard MCU IC. No matter which board failure, I still need to open up
the cover and to troubleshoot it. Once the cover was opened, I focused on the
power board first.
Visual inspection did not see any unusual problem be it on the components or the wiring cables.
The main fuse was
tested good thus I checked on the main filter capacitor and there was 325 volt
present at the two pins. I can actually go straight to check on the output DC
voltages at the connector but somehow wanted to show to you how to measure the
main filter capacitor voltage.
I further checked on
the surrounding components in the primary power section and all components
checked to be good.
I suspected it was the
power IC that have issue but the problem is the part number of the power IC was
removed. It is slightly difficult to know each of the pin function
especially to the beginners.
In order to remove the
guesswork if the power IC is the cause of the problem or not, I installed the power
module (5 pins) to test it out and see if the power will come back or not.
I connected to all the
wires to the 5 important points as shown in the diagram below. Sorry if the
diagram is blur.
Below is the photo of
a successfully installed power module and I tightened the power module to the
nearest casing to dissipate the heat. See the two photos below:
Once the power was
turned On, the picture immediately appeared.
This has proof that
indeed the original power IC got problem.
Conclusion- With the
external power module installed and the TV worked, this has saved me tremendous
amount of time. I do not need to know the exact part number of the power IC.
The installation time was fast provided you know where to solder the 5 points.
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