LCD advice on a Phillips 40pfl7705d/f7

[SunnyUSAF]

I have a Phillips LED backlit LCD tv model number 40pfl7705d/f7. I am goinf to attempt to attach a couple of images of what the pix looks like. The screen looks to be made up of 6 columns The far right 2 columns are correct but the rest of the columns that make up the picture are off, one is darker than it should be, the next two are lighter than they should be and the far left one is pixelated. I have examined the tv, as this unit is less than a year old, I didn't expect to find anything too far off spec. All the voltages are within spec and clean when examined on a scope. I looked for parts availability on this unit and found an ebay auction for a t-conn board and purchased it but it resulted in no change. What I am wondering is the same seller has the digital board with all the inputs and the main drive circuit that send the signals to the t-conn board. But before I start throwing good money at another board, I would like to know if this looks like a LCD problem or a driver circuit problem.





Thank you for you help.
Greg

[SunnyUSAF]

Re: LCD advice on a Phillips 40pfl7705d/f7

Anyone?.......Buehler? I have searched all over the web and cannot find anything related to this topic. Seems no one can advise me on whether this is a driver circuit problem or a lcd panel problem. I know that modern lcd panels such as this are TFT or twisted film transistor construction. I guess what I need is advice from someone with more experience that can tell me is the actual glass package lcd panel is damaged internally or if its just a driver circuit issue. Thats all.

[tom66]

Re: LCD advice on a Phillips 40pfl7705d/f7

Probably a panel problem - the tabs are separating.

Try applying pressure to the top of the TV, or lightly flexing the entire TV, and seeing if the problem temporarily disappears.

[SunnyUSAF]

Re: LCD advice on a Phillips 40pfl7705d/f7

Well thought I'd check back to see if there was any other advice posted. I did play with flexing the board and it resulted in no change. I built a holding fixture to hold the tv at a slight angle with a mirror placed under it so I could see the pix while the set was running. I also replaced the main board with a good new one and no change. So the only parts that remain as it left the factory are the lcd panel and the power supply board, and as I mentioned the voltages are all within spec according to the service manual and the voltages are clean when viewed on a scope. Guess it just frustrates me to no end that this set is junk with less than 2 years since build date (june 2010).

[Scenic]

Re: LCD advice on a Phillips 40pfl7705d/f7

tom meant the connection tabs between the actual glass panel and part of the little PCB on the panel, not pushing around on the mainboard.

Those ones (the brown flex cables)
http://hdtvtech.files.wordpress.com/...ble-before.jpg
http://i119.photobucket.com/albums/o.../SANY00132.jpg

It might be seperating from the panel (= poor or no contact)

[jettboat]

Re: LCD advice on a Phillips 40pfl7705d/f7

I have one of these sets now and suspect main board as there's no menu or sound. Voltages are good & clean, no change of the lines in the screen while twisting it so hoping the screen is good. this being the only post on this led smart TV I can find, wonder if there's a factory reset for it. may go on the back burner as I got 3 others to work on

[jettboat]

Re: LCD advice on a Phillips 40pfl7705d/f7

I changed the t-con board as it had a screw contact it and tore a trace up & a smd cap from the board. This happens from the stand mounting screws being to long, the t-con changed some of the screen lines (added more). Possibly this board is bad also came from used Toshiba. I have no o scope to tell if the signal is proper so another t-con will be attempted as there cheap.

[freakaftr8]

Re: LCD advice on a Phillips 40pfl7705d/f7

I have this seem the same issue with a bad t-con board on a sony 46 inch one

[jettboat]

Re: LCD advice on a Phillips 40pfl7705d/f7

The screen was bad or destroyed, someone sprayed cleaner that shorted the cof's of two bonding tabs, now its parts. The idea of putting the t-con / tab bonds down lower where fluids would destroy them from cleaning the screen, design foresight hummmm? never spray on the screen just the cloth.