Sony 55EX720 (windex/faulty picture)

[Htmatt]

Hi guys, I'm a long-time reader however new to posting here! Thanks to your previous expertise I was able to resurrect a Samsung LCD TV with faulty capacitors!👍

The mission I'm on today however, is repairing our Sony 55EX720 LED TV.

A couple of days ago my 3yr old thought cleaning the TV with windex was a good idea. We still had picture, however quite liney which then ended in "4 red blinks" and a blank screen.

After reading a couple other threads, I disassembled the TV focussing on the T con board and display panel. Now, I assume the windex ran to the bottom of the screen and onto the circuit board fixed to the display and has caused a short. I cleaned the boards down with some contact cleaner and reassembled. I then had a blank screen when powering up, and occasionally picture (and sound) with a solid blue (?) vertical stripe on the centre left hand side of the display about 6" wide. After re-powering a few times I then had a blank screen with "5 red blinks" instead of 4 previously and unable to get any picture or sound? 🤔

Following this, I played around for a while and discovered;
-If I remove both ribbons the TV has sound (obviously no picture).
-If I plug in the "left" ribbon only I have no picture.
-If I plug both in I have no picture.
-If I plug in the "right" ribbon only, I do have a right hand picture.

I'm wondering where to go from here, if it's worth replacing the t-con (having suffered a short?), or if the problem lies in the display and attached circuit board (being the component that would've been soiled). Should I try plugging the left hand ribbon into the right hand plug to see if the display fires up, identifying either a panel or board fault? (Was not sure if it could be done)

Any advice would be appreciated!

Regards.

[attainteddragon]

Re: Sony 55EX720 (windex/faulty picture)

ouch! this will most likely be something on the panel driver boards, on the left side. you can attach hi res pics of it, and someone might be able to help. check the ribbon connector that goes to the board from the t-con. you will be able to use one side to compare to other half. hopefully it will be something replaceable.

[angelos]

Re: Sony 55EX720 (windex/faulty picture)

The Electronics attached to the left side of the panel must have failed. Some voltage being pulled down. That's why when you only plug in the right hand side you have a a picture because you removed the short. This is very delicate work, i suspect that ones going to "file 13" (The rubbish bin). It could be the left hand pcb thats got the problem or even one of the COF IC's on the panel ribbons.

[Htmatt]

Re: Sony 55EX720 (windex/faulty picture)

Yep, not the best situation! However I'm determined to give it a good crack. Here's my current situation with the "right" ribbon only connected. (Sorry about iPad quality photos) 🤔

If people would like further photos, please ask.

[Htmatt]

Re: Sony 55EX720 (windex/faulty picture)

Further update. I just removed both ribbons and used the right hand ribbon on the left hand side (leaving the right hand unplugged). I seem to have picture on the left side now however I still have this nasty blurred streak through the middle?🤔🤔

[budwich]

Re: Sony 55EX720 (windex/faulty picture)

well, that is some progress but it appears that you are near the end. the vertical disturbance is likely associated with a tab near / aligned with those lines. You need to see the tabs but taking the front bezel off of the set. If you are lucky perhaps carefully inspection and cleaning at that tab might work. Likely not, but you never know. The cleaning fluid may have gotten into the "tab gluing" weaken it. After inspection, try light pressure on the tab to see if it changes the result. Good luck.

[Htmatt]

Re: Sony 55EX720 (windex/faulty picture)

Thank you, I appreciate the suggestion. I will have a play around later. Sounds plausible that the windex has run down directly over one of those tabs causing the issue. Regards.