How to test for standby voltage on the power supply board.
Troubleshooting in this video will apply to a TV that will not power on. If your TV will not turn on, either with the remote or by pushing the power button on it, try these troubleshooting steps.
In these troubleshooting steps, we will use a multimeter, to check for certain voltages. In order to continue troubleshooting, be sure you have the proper training, experience, skills, and equipment necessary to use a multimeter to check voltages in a TV.
Try all repairs and troubleshooting at your own risk.
The first thing that I can do is to check and see if there is a standby light in the front of the TV. Some TVs have the ability to show a standby light, while others do not.
If I do see a standby light in the front of the TV, that shows that I do have some power going to the front of the TV, but it will just not turn on. We will continue troubleshooting.
I have removed the back cover off the TV and I will use my meter to check the standby voltage on the power supply. First, identify the power supply in your TV. Then look for a cable that runs from the power supply to the main board. For this TV the standby voltage is 3.3 volts. Some TVs will have the test point on the connection, where the cable connects to the board. We have highlighted this test point in the video.
When I am testing the point, if I do have the 3.3 volt standby, then it shows that my power supply is most likely good and the main board should be replaced.
The next board I am going to replace is the main board. I will disconnect all of the cables and then remove the board from the panel by unscrewing it.
Then attach your replacement board to the panel with the screws and reconnect all of the cables.
When I am testing the point, if I do not have the 3.3 volt standby, then it shows that my power supply is most likely not working correctly and it should be replaced.
Here is a video showing how to replace the power supply board.
The first thing I will do is disconnect all of the cables from the board.
Next, I will remove the screws that hold the board to the TV panel.
After I have removed the screws, I can lift the board from the panel. Then I will take my replacement board, line it up correctly and then screw it to the panel, to secure it tightly.
Then, I can reconnect all of the cables.
This testing is a great place to start when troubleshooting these symptoms. In some rare cases, if you do have standby, and your TV will not power on, the problem could also be a component on the power supply board. However, to start troubleshooting, it is recommended to replace the main board first.
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