Sony KD-75XF9005 grey Picture but Sound. TCON or panel?

[iglitare]

Hi,

i want to repair a Sony KD-75XF9005 TV that initially only showed a grey picture.
Backlight seems to work, Sound (Setup menu after reset) works.
If i dissconnect the left FFC cable from TCON to panel i have half a screen on the right. If left cable is connected always only the grey screen.
Interchanged the cables, its always only the right side that is working. Always grey if left side is connected.
With my small knowledge i would think at least the cables are good.

Can this happen because of a bad tcon board?
Or is it always a bad/shorted panel?

[tiki66]

99% a bad/shorted panel. Do a tape fix

[Diah]

show please yours screen how it look

[Davi.p]

Hi, are you from Albany? The fault is probably a shorted capacitor on the panel strip board, left side, on the AVDD line (15v line).. check it first with ohm meter without power, i say to you the rest later..

[iglitare]

I can take pictures as soon as i am at my brothers house again (it´s his TV).
But it was just grey lit. With left cable from tcon to panel disconnected it was half ok, other half grey lit.

Hi, are you from Albany? The fault is probably a shorted capacitor on the panel strip board, left side, on the AVDD line (15v line).. check it first with ohm meter without power, i say to you the rest later..

Thanks for this info, i will check it! Unfortunatelly no, i am not from albany.

99% a bad/shorted panel. Do a tape fix

thats what i feared. I will try tape fix after i measured the cap Davi mentioned.

Before i try the tape fix, is there any way to determine what pin is shorted (measurements with multimeter or oscilloscope)? Or even blow up the short with overcurrent so that is just a open line?

And if i try the tape-fix, what lines should i tape?
I would guess the pins towards the center of the pcb where all the traces go to the big chip (left side pin 80 and lower)?

[Davi.p]

I thought so because of your nickname Igli Tare football player..

first i think you have bad cap, i'm convincted because otherwise you saw the half screen white not black, apart this if it would be the common fault with the tape "cure" , i feed doubts about the technique of the "short" killer, because i think the fault could not be a short in gate drivers, but a current deficit..

[iglitare]

I thought so because of your nickname Igli Tare football player..

Hillarious :-) but i am just an old fan of him since he played in a team i like

first i think you have bad cap, i'm convincted because otherwise you saw the half screen white not black

ok, that seems plausible, i will check in a few days if there is a shorted cap

apart this if it would be the common fault with the tape "cure" , i feed doubts about the technique of the "short" killer, because i think the fault could not be a short in gate drivers, but a current deficit..

Sorry, i tried to understand this sentence.
Do you mean taping does no work (reliably)?
Where are the gate drivers? directly on panel, unaccessible? Or on the small board of the Panel that holds the connectors to the tcon?
And where and why and what would be the current deficit?

[ivtv1]

These pins are always at the end of the tape.
https://www.youtube.com/shorts/3jD2pe_qUEE