TCL TV 75P8MR no backlight, LED strips OK

[Ozzitech]

Hi, have just joint this great forum and would appreciate any hints to repair the power board of my TV. Sound and faint image when lit with a torch, but backlight not turning on. Board number is 40-L402H8-PWD1CG.

The LED strips are all good, tested individually and all draw the same current at identical voltage; so guess the problem might be in the LED driver. Have just started to look into the board on the bench and will report back once I detect the problem, but in meantime any time-saving hints and schematic diagrams of this board would be great. Thanks!

Update: just found the driver OZ9976 presents a short circuit from Pin15 (VN) to ground. Faulty external components are excluded, as the short is still there with the pin isolated by cutting a small gap in the PCB track. At this stage I assume the IC is damaged, reason unknown.

The datasheet of the driver is very basic, anybody else experienced a similar fault or found a better datasheet ?

[Ozzitech]

Update: just found the driver OZ9976 presents a short circuit from Pin15 (VN) to ground. Faulty external components are excluded, as the short is still there with the pin isolated by cutting a small gap in the PCB track. At this stage I assume the IC is damaged, reason unknown.

The datasheet of the driver is very basic, anybody else experienced a similar fault or found a better datasheet ?

[Ozzitech]

Update and correction - Pin15 is connected via an invisible track under the chip to GND, so back to debugging other problems..

[markusdd]

I think you narrowed it down already.

check all the inputs that are ground and supply to the IC as per the app schematic. If they are all there, check if you get switching on the transformer output, also check the transformer coils all have continuity.

Last, check that none of the caps around are shorted. If this is all done I would say calling the IC faulty is reasonable.