KDL-43W805C - backlight and sound work but no picture

[Dobsuk]

Hi all.
I am about to investigate a issue with that Sony KDL-43W805C. So, the tv is working except the picture. When i switch it on the backlight come on and the picture is going trough different states - with lanes, colors etc:







I read some threads that it could be software issue and need to upgrade the software but i could not do that following these steps:

1. Download the SOFTWARE corresponding to your REGION and LANGUAGE from the official SONY SUPPORT page
2. Follow the instructions to save it in USB
3. Connect and turn on the TV, wait for screen image to go
4. Connect the USB to port number 1
5. Press "HOME" on the REMOTE CONTROL
6. Press UP ARROW once and then ENTER (CENTER BUTTON)
7. Press DOWN ARROW once and then ENTER
8. Press DOWN ARROW three times and then ENTER
9. Press only ENTER again
10. Press LEFT ARROW once and then ENTER
11. Wait about 2 minutes and press LEFT ARROW again once and then ENTER
12. The power indicator LED should start flashing amber, that indicates that the update started if it does not flash wait a few more minutes and press LEFT ARROW again once and then ENTER ...

and

1. Download the SOFTWARE corresponding to your REGION and LANGUAGE from the official SONY SUPPORT page
2. Follow the instructions to save it in USB
3. With the TV off in standby... Insert USB pen drive to USB port of TV
4. Pull Out the AC plug and wait 10 second (considering the charge of AC adaptor)
5. Press and hold the side Power Key for 5 seconds and re-insert the AC plug at the same time
6. After 20-30 seconds, the LED is turn to Amber and blink
LED blinking indicates “Under SW Update”

I think i did factory reset using Vol down and Power button combination because every time when i switch it on now i can hear some music and i believe it is coming from the welcome screen. I am not experienced in this but it sounds like T-CON board issue. Anyway i am going to open that TV in the next days but just wanted to hear some more suggestion and will be glad if you give me some advises.

Thank you!

[nomoresonys]

Re: KDL-43W805C - backlight and sound work but no picture

Maybe try those blind firmware updates with a different usb drive if you haven't already.

[budm]

Re: KDL-43W805C - backlight and sound work but no picture

Please attach good clear pictures of the whole back side of the TV showing all the boards.
Do you know if this LCD panel has integrated T-CON board as part of the LCD panel?

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

I have not open it yet. But i will upload photos as soon as i start work on it. Just wanted to have more ideas and to hear more suggestion before to start.
nomoresonys - i will try with different usb but i think it will not help
Thank you.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

Ok guys. I found time today for this tv and i've got some success but just a little These are the boards:

So i tried to remove some of the ribbon cables and then i saw full SONY logo then Android starting but in few seconds screen disappeared and i saw 6 blinking codes which should be normal because of the disconnected cable. It was the same with the other ribbon disconnected. Then i connected both of the ribbon cables and the tv was working normal for a while:

I did the first settings and then checked for updates but it said that it is up to date. Then the screen went white again:

And now i have it working sometimes and then it is going to white or other colors screen.
I am waiting for some advises. Thank you

P.S. I checked the firmware version and it is 4.33. The last one on the sony's webs site is 4.35. It could not find it automatically and now i am trying to update it via USB drive but it is pain - waiting to come on for a while

[budwich]

Re: KDL-43W805C - backlight and sound work but no picture

you might still trying a usb update as opposed to letting the "system browser" look for an update on line. The "usb process" may bypass "you are already updated" checks and just check to see that the file type is correct along with any basic checks (ie. checksum, etc).... in essence being at a "boot load" level as opposed to full operating mode.

Some of the earlier display pictures don't give a good feeling about the panel or connections to.... this may be stopping the system from fully operating.

[nomoresonys]

Re: KDL-43W805C - backlight and sound work but no picture

May be a dirty connection, make sure the connections are clean, try unplug and re-plug on your connections, can clean the ribbon connectors with a pencil eraser or a q-tip and some isopropyl alcohol, not to hard they can be delicate.

[nomoresonys]

Re: KDL-43W805C - backlight and sound work but no picture

I can't tell if you have a stand alone tcon there but a whitewash display can mean a bad tcon board.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

Ok. I updated it succesfully via USB:

And i was able to monitor whole of the updating process about 15mins and the picture did not go off. Then it restarted few times and when i switched it on again i saw some color lines again and then the picture came on. I am watching it now only in TV mode only to check if the picture will go off again.

[budwich]

Re: KDL-43W805C - backlight and sound work but no picture

good.. glad you got further and potentially now appear to have a working set. If you can, I would suggest keeping your USB handy... :-) Further, input some static color bar test pattern to look at closely to see if you notice any "unusual display things" to indicate any potential panel issue. Also, you might want to try some "android based" apps to see if this causes "pressure" on the main board which may indicate possibly a heating issue / poor board tracks / etc. All this just see if you can find a "root cause" and get it addressed while you got it opened up.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

Unfortunatelly it is the same �� The picture is comming on and off when it wants.... I cannot link it with anything. The only thing that i found now is that this colored lanes depends on the color of the background.

This color is from Android first welcome screen after factory reset (because i did it again after the firmware update). If i am in the setting screen where the background is grey/blue i will see lanes with this color.

[budwich]

Re: KDL-43W805C - backlight and sound work but no picture

you need to remove some of the frame member / covers along the bottom of the set to provide a better view on how things are interconnected. From limited "reads" on a previous thread dealing with a TCL / Roku based set, there is "significant comms" between the main / android based operating system and the tcon / panel drivers. If that is interrupted for what ever reason, the set (tcl) seemed to lock up. Of course, this was based mostly on observations as opposed "design intent knowledge".

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

This is the TCON board. It is so hard for access and quick tests as it is just behind the mainboard.

[nomoresonys]

Re: KDL-43W805C - backlight and sound work but no picture

Try cleaning those ribbon ends, sometimes they just get dirty or loose.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

I did it but nothing. It is the same and the same. And i cannot see clear picture does not matter if i disconnect some of the ribbon cables or not. I think it is something about the TCON or....i do not know...

[budwich]

Re: KDL-43W805C - backlight and sound work but no picture

because of its position, troubleshooting of the signal from the tcon past will likely be ugly. As you see on the tcon, there are a number of voltage points that can be found (eg. Vxxx... but not VGAxxx which are likely image signals). Anyway, if you can't turn on the set and measure the values at those points with the main board in place, then you are going to have to trace / transpose those points to accessable points on the bottom edge boards that the tcon to panel cables connect to. Voltages of interest might be some thing like VCOM, AVDD, etc. It is likely one of those voltages is not there.

One other question: when you disconnect one of the cables from the tcon to the panel, what happens to the display on that side? what happens if you do the other side with a similar test? Post a picture.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

Voltages of interest might be some thing like VCOM, AVDD, etc. It is likely one of those voltages is not there.

I will try to measure them tomorrow.

One other question: when you disconnect one of the cables from the tcon to the panel, what happens to the display on that side? what happens if you do the other side with a similar test? Post a picture.

Just that half of the screen is going white and the other half is working how it wants... I can make photos tomorrow as well. I've had enough for today.
I cannot make it work normal in the last few hours. Thank you all

[budwich]

Re: KDL-43W805C - backlight and sound work but no picture

no problem. Just want to make sure of what is what as "no display" can mean a lot of things especially in terms of subtle things like what you initially posted. The question would b: does the half go "clean white" or are they "bands of white / grey" as you posted earlier. Expectations would be "nice clean white" on the disconnected side.... but those expectations sometimes are different depending on the set / maker.

This is starting to sound similar to a TCL "story" not long ago.

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

Ok. I took some measurements:

AVDD: 15.68V
VSS: 7.09V
VCOM: 6.47V
VCOM_CF: 6.47V
VGHD: 0V

I found and that i have got some display changing when i tap on some of the ribbon cables but not everytime. It is so temperamental:






Here are some photos of the ribbon cables disconnected.
Right side disconnected - I can see clear white right side but some times i can see and one darker part of that half. Some time it is just clear white:



Left side disconnected:



I forgot to mention that these lines are comming when i tap/move the ribbon cable on the middle. Nothing happens if i tap on that end which is connected to the panel.

P.S. Nothing is changing now does not matter if i tap on the cables or not

[Dobsuk]

Re: KDL-43W805C - backlight and sound work but no picture

I watched this video now where they removed some of the direct signal connection. But i think it is the same as the tape method. I tried to put some tape on the ribbon cables but no changes.
I watched and this video where the symptoms are more similar than mine and they are fixing it with TCON cnahging.
And both TVs from these videos are with similar models like my one.