I will be happy to assist you with this question.
I understand that you have the STB 5V going into the main board.
This is all the main board needs to function at this point.
Now,please push the power button and monitor with the meter on Vdc,the power on command from the main board into the power board.This should be a pin on the power board connector,that should go to about 3-5V when power button is pushed,
This command is supposed to wake up the power supply ,and this should generate the other switched voltages.
My suspicion is that the main board is defective and will not generate this power on command.
The part# XXXXX this board is:
Unfortunately it is very hard to find,there is a very low availability for it.
If the Power On command is coming into the power board ,but still no output voltages from the power supply=defective power board.
Part # XXXXX this is:
A good place to start looking for parts is :
I hope this helps,
Please leave a positive feedback if you feel I did my best to answer your question.It will be highly appreciated.
Thank you and have a good night!
The readings from the power board connections are as follows (relative to GND):
NC - empty pin
GND - empty pin
V_IPWM - 2.84 VDC
BL_ON - 0.02 VDC
PS_ON - 2.80 VDC
GND - 0 VDC
5V - 4.96 VDC
5VS - 4.96 VDC
12.5V - 11.99 VDC
12.5 V - 11.99 VDC
NONE of these readings changed when I pushed the power on button.
When I disconnected the main board all of these pins read 0 VDC except the "5VS" pin, which read 5.00 VDC.
I did find the main board available from one source. just want to confirm that based upon this information you still believe the main board is the problem before I order it and accept your answer.
Thank you in advance.
Good job with the voltage readings!
You are perfectly right-the tv needs replaced the main board.
The way it was supposed to act,if was a good one ,is ,once you push the power button,and only then-the PSON should change from 0V to round 3V,then couple seconds after this,the BLON should get also "high" between 3V and 5V.
Since your PSON is always 2.8V and BLON is 0V=defective main board.