sony kdl-55ex720 i have backlight and a blank stare on my face

[smai]

when the unit is powered on i will get the sound of static (see video) OR the sound of analog tv with bad reception kind of static for about 5 seconds then blank screen, some buttons make noises some dont, cant change inputs, cant bring up any menus, its just a black lit screen.. (actually now that i think of it, when i 1st plugged it in it showed static like channel 3 on analog but it faded to black and now is only)

the video attached however is me "resetting" the tv by holding the up arrow on the remote and pressing the power button strange result

i just inherited the TV so im not sure what led up to this, i found the service manual which ill upload here for future searchers

my gut is telling me the main board is toast maybe a corrupt firmware or bad flash or something on the main board failed, but my brain is saying that would cause a blinking light so i dont know

thoughts anyone ?

http://s59.photobucket.com/user/joeb...baf71.mp4.html

[freakaftr8]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

I would start by pulling one ribbon cable from t-con board to panel and try powering it up see if half the screen comes on then if that side doesn't replace that cable and pull cable on opposite side and see a screen comes on That side. what we're looking for is a possible short in the main panel itself but this could also be a tcon for issue

[smai]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

i just briefly talked to the previous owner they said they cleaned it with windex and it happend.... i dont think that would do anything unless you doused it in windex

thanks ill try that

[R_J]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

I see that the T-con is located at the bottom of the panel,, I will guess that the windex ran down the screen and onto the lcd display circuits where they connect to the actual panel.

[freakaftr8]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

if you're lucky it might have just shorted out the Tcon Board and the panel still is still okay

[smai]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

I would start by pulling one ribbon cable from t-con board to panel and try powering it up see if half the screen comes on then if that side doesn't replace that cable and pull cable on opposite side and see a screen comes on That side. what we're looking for is a possible short in the main panel itself but this could also be a tcon for issue

i did this no change

I see that the T-con is located at the bottom of the panel,, I will guess that the windex ran down the screen and onto the lcd display circuits where they connect to the actual panel.

YES this is the case i found blue residue on the board that is hard connected to the actual display, it was on one a small area and some of the connector

So i pretty much took the whole TV apart and cleaned up all the residue and the connector still same result and again its the whole screen not just one side, i have inspected the t-con nothing looks obviously bad and the 2 fuses are continuous

Any thoughts on more diagnosing/testing or which board to replace?

[smai]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

if you're lucky it might have just shorted out the Tcon Board and the panel still is still okay

if the t-con didnt get wet could it still have shorted out from the other board getting wet?

do you guys think im fighting a losing battle here with a "windex wetted" panel ?

[smai]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

just an update i was able to update the firmware (blind) and now i can get the audio to play (only HDMI tested) but still no video it seems like the TV is working as normal besides displaying the video, the chip on the t-con board get pretty warm

i also attached the service manual, for future reference for anyone searching, and it seems like theres no real way of testing, just replace and if it doesnt work replace the next board and so on

what do you think shot display ? t-con? BATV? LD?

[truep]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

I have several sets with corrosion on that board. None were repairable.

[smai]

Re: sony kdl-55ex720 i have backlight and a blank stare on my face

so i got the TV to display random moving lines with some color only on one side of the screen by disconnecting the other side, the side that displayed something was the windex effected side

does this give any clue on the part that is at fault? would i be wasting $60 on a t-con board by giving it a shot?