Sony Bravia KDL-40V5100 Black Screen No Backlight

Thank you so much for your answer @oldturkey03! I poked around with my multimeter and was able to get voltages and connectivity but struggled with getting current readings. I’ll put fuses in this comment and ribbon cord connections in another!

Fuses as they are listed on board:

F70013 15A/24V: Good Connectivity 12V

F5505 XX: Good Connectivity 0V

F5501 XX: No Connectivity 5V

F5503 XX: No Connectivity 0V

F5504 XX: No Connectivity 5V

F101 0.5A/50V: Good Connectivity <0.15V

Starts at 0.15V and trickles down to 0 as multimeter placed on fuse

F3000 0.5A/50V: No connectivity 3.3V

F1000 XX: No Connectivity 12V

F1001 5A/24V: Good Connectivity 12V

F7002 3.15A/24V: Good Connectivity 12V

F2000 4A/24V: No Connectivity 15V/1.5V*

Had good connectivity with 15V but when trying to measure current caused spark and only read 15V on one side and 1.5V on other side with no connectivity

Connections on Board:

CN2000 (connect with speakers)

Pin1 1V | Pin2 1V (to speaker)

Pin3 0V | Pin4 1V (to other speaker)

CN1003 (connect with power board)

Pin1 3.33V (Power On)

Pin2 3.4V (AC Off)

Pin3 3.3V (3V Standby)

Pin4 and Pin5 15.4V (Unreg 15V)

Pin6 - Pin10 0V (GND)

Pin11 - Pin13 12V (Reg 12V)

CN1004 (connect with power board)

Pin1 0.5V (Dimmer)

Pin2 1.13V (Backlight On)

Pin3 1.9V (INV_ERR)

Pin4 0V (GND)

Pin5 0V (Balancer_error)

CN3004 (connects to power light and side panel tv control)

Pin1 3.3V Pin14 3.3V

Pin2 3.3V Pin15 0V

Pin3 0V Pin16 Not able to read*

Pin4 0.5V Pin17 3.3V

Pin5 3.3V Pin18 0V

Pin6 0V Pin19 0V

Pin7 3.3V Pin20 0V

When trying to read pin16 the tv turned off suddenly, when VCC probe was removed from pin the tv instantly turned on again

Other interesting things I found:

USB with LED indicator is inserted into either USB port on main board the LED indicator does not light up, and optical port only lights on start and shutdown

@dragontv when you say no connectivity are you referring to “ continuity”? Your findings seem to further point toward a bad main board.

Turn your TV on and in a darkened room, shine a flaslight beam at an angle at the screen. See if you can make out any shapes silhouettes etc. if so its more of a backlight issue If you do not see anything its a mainboard issue first than a T-Con due as evidenced by the clicking on the power-board and the voltages

@oldturkey03 My bad I meant continuity! I tried pointing a flashlight at the screen and could not see any outlines, shapes, or silhouettes. I tried it with everything connected, just the inverter and main board without the T-Con, with the T-Con and main board without inverter, and with just the inverter and T-Con without the main board. Since this seems to point at the main board is there a way to test the T-Con independently to see if both the T-Con and main board are failing? Thank you so much for your assistance!