Sharp LC-40UG7252K black screen

[Wodger]

Good day all,

As title says, black screen. Replaced hot side and largest cold side capacitors on power board as were reading erratic and TV was dead (no power light).

Following replacement, power led now illuminates, changes from red to blue on pressing TV joystick, still black screen. Connection board appears powered (optical sound led on). Slight crackling from speakers.

Checking led driver voltage reveals voltage falls off after power on from pressing joystick (drops to zero).

Attached picture of power board.

Next check steps appreciated.

Thanks,

Pete

[Wodger]

Hi everyone,

So, had some time to look at this. Appears backlight issue as after throughly cleaning screen (disgusting!) sharp logo and "no signal" visible with flashlight.

Found layout schematic for psu board which I have attached here for others should they have the same psu board (appears common for sharp TVs).

While I was tracking down the problem and finding no 380v passing through q201, but 120v on gate, I inadvertently caught the leg with my probe and blew R218 (teach me also to take picture of back of board for correct value replacement smd should something like this occur).

Will have to look at this again once I figure out the smd value and getting a replacement to fit...

Pete

[Wodger]

Hi everyone,

So, after a horrible trip to Turkey (not for pleasure sadly), I'm back and keen to get this board working properly.
I'm stuck with what resistor value I need to fit to replace the blown SMD R218.

Attached is the screen grab section of the schematic but it doesn't list values for the relevant components. Is anyone able to advise?

Thanks,

Pete