Sony KD-43XE8005 with sound, backlight, no picture

[ronni]

I have a Sony KD-43XE8005 with no picture on the TV when powered on. Audio and backlight work ok when powering on. Solid white indication light showing on front of tv bezel.

When removing the left hand ribbon cable from the T-con board, a white image is displayed on that half of the screen and a black screen is shown on the right. If I gently rub the ribbon cable on the right an image or purple black bars appear. The cable doesnt appear damaged, and if swapped with the other ribbon cable the same flickering symptoms can be seen.

Removing the LVDS cable results in neither a picture or white screen being displayed. When the right hand T-con cable is removed nothing is shown on the screen, only a backlit screen.

So far I've changed the T-con board for one of the same part number with no improvement. Reading through other posts it points to a faulty panel, but the 'flickering picture when rubbing the right hand t-con ribbon cable' is throwing me off, so I've ordered a replacement ribbon cable.

Any ideas of what to test/replace next? Thanks

[nomoresonys]

maybe try the tape cut-off method.

[CapLeaker]

The skinny little board with the tab bonds going to the LCD, look there for shorted SMD cap(s). There should be also test points to measure voltages.

[ronni]

Thank you both for the replies. I'll try taking a closer look at the caps, test points and the tape cut-off method

[ronni]

I looked into the tape cut-off method, the CLK lines are only on the right (working) side. So I taped the clock lines 1-8 but there was no change on the left hand side of the screen.

I'll take a look at testing all the caps on the panel interface boards

[Jackplug 123]

Take a look at my posting a 49 inch Sony, solution posted last Sunday, looks like a similar TCON board too.cheers Jackplug 123

[ronni]

Originally Posted by Jackplug 123

Take a look at my posting a 49 inch Sony, solution posted last Sunday, looks like a similar TCON board too.cheers Jackplug 123

Thanks for the message. I saw your thread and was following your progress. It's great that you got it working but doing the same on mine unfortunately doesn't have the same outcome. I'll try identifying any faulty caps and go from there

[Jackplug 123]

Shorted decoupling caps on the thin driver board could be the problem.
I was about to check mine,but to expose the board involved a bunch of screws removing on the bottom lcd screen frame section.Decided to try the tape method first, my next task is to isolate the bad clock line or lines out of 8 lines.
However the initial result was surprising good picture.
Have a look at Michael Dranfields videos on YouTube,one deals with a set with shorted caps.He uses a milli ohm meter to narrow the field down.Good Luck.

[nomoresonys]

good call, Michael has good videos.

[ronni]

Thanks Jackplug. Took a look at his vids. I've found a couple of shorted caps on both sides of the screen. Looks like I'll be building a milli-ohm meter next!

Michael Dranfield's video for future reference:

https://youtu.be/77tymvTJDxo?t=887

[nomoresonys]

Actually post #3 said to test those caps.

[ronni]

Originally Posted by nomoresonys

Actually post #3 said to test those caps.

CapLeaker did indeed say to test those caps. Unfortunately I was in the same position as Jackplug...taking the easier route of trying with the tape method first. When this didn't work I removed the rest of the frame and located the caps. Michael Dranfield's video will help in locating the shorted cap through the use of a milli-ohm meter

[Davi.p]

there's no need of milli ohm meter, cap finding can be made by an average multimeter in ohm..

[nomoresonys]

^if you would have bothered to watch the video, you would discover that yes many times a milli-ohm meter is needed to find the bad cap efficiently , why do you think they were invented.

[ronni]

Just an update...I built a milli-ohm meter to identify the bad cap, desoldered it and now the previously white side of the screen is working but with a missing large vertical strip. The left side of the screen is now white so I'll go re-check those driver board caps

[Diah]

what is that on the ground ??? the TV COFs!!!!

[ronni]

Originally Posted by Diah

what is that on the ground ??? the TV COFs!!!!

The COFs are covered by the metal bracket are not touching the ground

[nomoresonys]

Did you replace the shorted caps?