Hi @compjinxmagic ,
Disconnect the power from the TV and then reconnect all the boards as per normal.
Then disconnect the mainboard cable from the power board.
Reconnect the power to the TV.
The backlights should turn on and stay on. Obviously there will be no picture because the mainboard is disconnected.
If the backlights blink then the problem is either in the power board or the backlights.
Disconnect the power to the TV and then disconnect the LED power cable at the power board.
Reconnect the power to the TV and measure the voltage between the LED+ leads and earth at the power board.
The voltage should be >250V DC. If it is then the problem most likely is in the LED array as the voltage at the power board is OK. The voltage measured is the open circuit voltage as there is no current flowing to the LEDs - no cable ;-).
It may be easier to get a LED backlight tester - examples only to test the backlights as using one of these means that you don’t have to power up the TV and can test individual LED strips. There are videos on YouTube that show how to test LED strips using a backlight tester.
Did you test the voltages at the connector pins on the power board where the cable to the mainboard connects BUT with the mainboard cable disconnected and the power connected to the TV as suggested?
What voltages do you get on each pin?
Here’s a zoomed in image taken from your image of the power board showing what I think are the voltage values for each pin.
It is too blurry to make out properly so hopefully it is what I think and it is a pin voltage chart. It is just below the connector.
Click on image to enlarge for better viewing)
Be safety aware when testing here. DO NOT short out any pins and be careful as you are also very close to the “hot” side of the board i.e. that is where there is either exposed very high DC voltage or exposed possibly lethal AC voltage!
Also if you changed the power board and the problem remains but now at least you know that the backlights are OK, it’s pointing more towards the mainboard. It’s not unknown to have two problems in a TV. You just have to fix them one at a time
If the 2nd last image you posted is the tcon board I think that there is a fuse.
Here’s a zoomed in image from your image I turned it around so that I could read what it says on the board
I think that it says 125V 5A but I may be wrong, also there won’t be 125V at the fuse, it is only that rating for the current flow but still place the voltmeter to read 200V to be safe
If the last image is of the the burnt chip that you’re talking about I can’t see it but no surprise there as my eyes aren’t what they used to be, but if it is on the mainboard it is looking likely that the problem is there.
(click on image to enlarge for better viewing)
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