XBR-55X850 turns on but no pic no 12v on t-con

[budm]

Re: XBR-55X850 turns on but no pic no 12v on t-con

https://www.badcaps.net/forum/attach...0&d=1525751962

I need better pictures to be able to read the marking of all those pins of connector CN6401.
You will need to report the Voltage readings of all those pins, except GND pins, to se if any other Voltages and control Voltages are missing or not.
I also need to the P/N of the power supply board as printed on the sticker on the power supply.

[Davi.p]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I have repaired one 60" Sony where a fault on the screen produced self protection by mainboard/power bd circuitry, best wishes.

[nomoresonys]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I have repaired one 60" Sony where a fault on the screen produced self protection by mainboard/power bd circuitry, best wishes.

So how did you fix it?

[Davi.p]

Re: XBR-55X850 turns on but no pic no 12v on t-con

In a very strange manner... with some luck... check "KDL-60ex700" but its a long thread...

[Louis82]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I'm currently having the same exact problem. I believe the issue is the screen (agree with David). I have tried multiple firmware updates with USB and everytime the results are different, which is strange.

I will explain in details what happened every single time below:

1- After USB firmware install, the TV will not respond to any button or remote control. Unplugged TV, plugged back in and still the same until I disconnect the 5 pins cable that goes from power supply to T-con, then TV started up. Backlight came on and I could see that Tv responded to remote control as I can see the white light kind of flashing when buttons on remote where pressed. I disconnected the LVDS cables and I was still getting the same. I turned off TV, plugged everything back in, turned back on and TV went straight to green and amber flashing.

No matter what I did the TV will go straight to green and amber. I went again to install firmware and....

2- No response to power button until i disconnect 5 pins cable and LVDS cables. Tv responded to remote but no backlight. Plugged back in and green and amber light blinked again.

3- I installed firmware again, but this time before I turn tv on , I remove the LVDS from screen to T-Con and left everything else plugged in. I turned tv on and straight to green and amber flashing lights.

4- I tried again (2 days troubleshooting this animal). Connected screen back to t-con, installed firmware, disconnected LVDS and 5 pins cable and again green and amber light

5- Installed again, now everything is connected except the 5 pins cable. Tv responds to remote, white light on bottom acting normal. no picture, NO BACKLIGHT, but again at least it responds to remote power button on and OFF.

This is where Im' at right now. Luckily this is not a customer TV.

Any thought everybody?
David does this sound like your TV where you said you determined it was a bad screen?

[Louis82]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I meant Davi.p - any guidance you could provide?

[Davi.p]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Hi, first of all don't take in to consideration much my previous suggestion about Sony.. Designs might be different, then i ask you, the 5pins cable is the supply for the tcon i guess.. right?
I'm not sure you reported here the right sequence you made, because something doesn't turn back to me..
Now watching the behaviour of a Panasonic led with Samsung screen that i have, i suspect that some designs of panels have a tcon that protect itself when sensing panel shorts/abnormality and writes an error flag on its eeprom. Then when next tv boots it receive from tcon through i2c a deny or error command and tv switches off tcon and also BL. Now maybe, as Freakaftr8 says, in this Sony design an update procedure would set back the tcon eeprom to a previeus state or simply update it with new settings. This is why it unlocks. So i suggest you to feed some supply to the panel remembering that the VCC must be always present due to possible damage to the drivers, and watch if some of the caps on the panel's boards keep very hot then shorted like Freakaftr8... if you find it then do the upgrade procedure, bye.

PS: yes my Sony had a bad screen, but fixed in a strange manner, no short on it however..

[boonehockey]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Hello, I have a Sony XBR-55X850C and I have no backlight, no display but I do have sound.

When I first turned the tv on it flashed 6 red LEDs. Looked up the code and it said it could be the backlights or the main or power supply board. I opened the tv up and seen that the main board was getting voltage for a few seconds then shutting off. I disconnected the T-Con board, the backlights came on. It was displaying a series of colours. I turned the tv off and plugged the T-Con board back in. When I turned it on the LED say there bottom was flashing between Orange and Green, indicating it needs a firmware update. Followed the instructions on the Sony website for updating with a memory stick. It does say to follow the instructions on the screen (can't do as there is no display) . If I press the power button I get a white LED to come on, still no display or backlights. The 6 red LEDs have not come on since. I tested the backlights and they still work. Unplugging the T-Con board doesn't display the colours either.

Below are the voltages I'm getting with the power on.

Backlight 1+2 68V

1- NC - No Pin

2 - DC_dimmer 0V

3- BL_ON 0V

4 - PWM_DIMMER 0V

5 - STBY_3.3 3.47V

6 - BLINKING 0V

7 - AC_OFF_DET 3.48V

8 - BL_ERR 2.5V

9- POWER_ON 3.4V

10- GND - n/a

11- GND - n/a

12- GND - n/a

13- REG12V 12.6V

14- REG12V 12.6V

15- REG12V 12.6V

16- REG12V 12.6V

17- REG12V NO PIN

18- REG12V 12.6V

19 - GND n/a

20 - GND n/a

21 - GND n/a

22 GND n/a

23 GND n/a

24- TCON_ON 0V

25- TCON_VCC_12 0V

26- TCON_VCC_12 0V

27- TCON_VCC_12 0V

28- TCON_VCC_12 NO PIN

[nomoresonys]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Not exactly sure, isn't "8 -BL_ERR 2.5V" suppose to be 0 when functioning properly?

[boonehockey]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Yeah I would assume the backlight error voltage should be 0V, any idea what could cause the main board to throw that voltage?

[budm]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Bl-error generated by the backlights circuit to tell the main board the condition of the backlights circuit.
Are you getting 6-blink for backlights error code?
See service manual for Blink codes:

[boonehockey]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I did originally get the 6 blink error code, but it has not come back since I unplugged the t-con board and got the series of colors to show up. My next step is to open the panel up and take a look at the backlights individually with my backlight tester. If there was a few LEDs that wont turn on, will this cause the BL-error and essentially shutdown the backlight array?

[Nick's Tvs]

Re: XBR-55X850 turns on but no pic no 12v on t-con

David.P has good info to give you guys, and I am sure can help you fix a lot of TV sets. However we shouldn't be asking him what he did with the KDL-60ex700 1080P model manufactured in 2010 and apply that information to this 2015 4k tv this thread is about. These TV's were designed very differently, a lot of the successful tests performed on the 2010 model do not apply to this model.

Regarding the initial issue from hmendez86 these TV sets very often have main board failures and what you are experiencing is most likely what freakaftr8 posted in comment 17 stating that you will need to download the software from the sony website as you most likely have a software issue.
I highly recommend that with power disconnected you double check the LVDS ribbons, and make sure those are both in good condition, as well as properly connected. I have a feeling there is history on this tv involving attempted repairs from your friend or someone else that you haven't mentioned or your friend hasn't mentioned to you. These LVDS ribbons are not your usual ribbons and often get damaged, so please check the contact points on the back of the ribbon and make sure they look like they are brand new. Re-seat the ribbons and let me know if you have a hard time with disconnecting and reconnecting them. I can point you to a video that demonstrates how to engage the clip mechanism on these.
Once done, download the firmware from the Sony website linked below:

https://www.sony.com/electronics/sup...loads/00016190

per the instructions go ahead and unzip the file using 7zip per Sony's recommendation. Once unzipped put that file onto a blank flashdrive that has been formatted to FAT32.
Once done, you need to have the TV unplugged, plug in the flash drive into the main board with every connector properly connected as it should be, and then plug the TV back to power.
If the pairing procedure begins, it will be indicated by a slowly pulsing white light. You may need to wait 15 seconds before it begins. Don't try to turn the TV on or off while this is happening. Be patient. If nothing happens, go ahead and turn the TV on. Once on, go ahead and press the power button located on the TV itself and keep it pressed in until the TV turns off. Once off, the TV should start applying the firmware pairing update. This can take up to 1 hour. Once completed the TV should turn back on and provide you with proper picture.

boonehockey, budm is correct 6 blink code = backlight failure guarantee.

If at any point the LVDS are disconnected from the T-con however and the TV is powered on then the main board will throw an error stating it is not paired properly with the T-con and panel and will automatically show that amber and green flashing light. When this happens, you will need to follow the same steps as above, Once you do so the pairing proceedure should begin and be indicated by the light no longer producing an amber and green color code but instead a slowly pulsing white light. When this happens DO NOT TRY TO TURN ON OR OFF THE TV, PRESS THE POWER BUTTON OR DISCONNECT THE FLASHDRIVE OR TV FROM POWER. Let the main board pair with the tv, it can either take first try and will be 1 hour to pair, or will stop after 30 minutes and show amber green again. If the second of the two occurs simply disconnect the TV from power and plug it back in to start the second portion of the pairing procedure.
This will happen almost every time you decide to disconnect the main board from the T-con and turn the TV on.
So once you have this taken care of, replace your LED's and don't test them until the TV is fully put back together. It won't work unless every piece is back in place.
These TV's are a huge pain, but once you understand what you can and can't do with them, they aren't so bad.

Also for all of you that don't get picture on screen but do get backlight to turn on, you will also need to follow the same steps. It is extremely rare these panels fail, but it is extremely common to see main board failures with exactly these symptoms. TV turns on and off, no picture but can hear sound. Somehow the main board is not communicating with the T-con and panel and needs to have the firmware from the sony website reinstalled in order to work. This is also required after replacing main boards.
If any one has issues, just post back and I will do the best I can to answer questions.

[nomoresonys]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I asked him how he fixed it because I wanted to know, I believe he made it CLEAR that it was a different model tv.

[boonehockey]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Thank you Nick's TVs for your detailed answer. I currently have a friend who does board level repairs looking at the main board to see if he finds any issues. When I get it back I will do the pairing procedure again. I have tried it 5 or 6 times, are you aware of any on screen prompts or is it simply plug the memory stick in and leave it?

[R_J]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I did originally get the 6 blink error code, but it has not come back since I unplugged the t-con board and got the series of colors to show up. My next step is to open the panel up and take a look at the backlights individually with my backlight tester. If there was a few LEDs that wont turn on, will this cause the BL-error and essentially shutdown the backlight array?

The short answer is yes, it will shut down the backlight circuit.

[Nick's Tvs]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I made a video explaining the entire process since it can be difficult and we have had so many people ask questions about it. There are no prompts on screen, this is kind of a blind procedure which is why it is a bit tricky.
This video has every single possible issue one can encounter when trying to pair the main board, as well as how to solve those issues.

https://www.youtube.com/watch?v=3kYP...ature=youtu.be

[Leo wafula]

Re: XBR-55X850 turns on but no pic no 12v on t-con

Just changeg the LVDS cable and it worked backlight turned on and pictures

[jason123]

Re: XBR-55X850 turns on but no pic no 12v on t-con

I made a video explaining the entire process since it can be difficult and we have had so many people ask questions about it. There are no prompts on screen, this is kind of a blind procedure which is why it is a bit tricky.
This video has every single possible issue one can encounter when trying to pair the main board, as well as how to solve those issues.

https://www.youtube.com/watch?v=3kYP...ature=youtu.be

Hi there,
Same problem with the XBR-75X850C - Dim white light comes on the front indicator, no backlight.

With power down, tested the LEDs, no issues, they all lit fine.

Disconnected the LVDS cables from main to TCON, the TV started cycling colors on the screen (white, Red, Green,..)

Powered off, reconnected the LVDS cables and powered up, sure enough, green amber. Did the pairing again (thank you for the video!) and after the pulsating white light for a while turned off. Turned on manually, same as when I first started. No backlight or activity on screen.

I got another replacement main board - does exactly the same thing after pairing.

Now from this testing, I can deduce the backlight is ok, the panel is ok, TCON is driving the colors so (maybe) ok?

Where do I go from here? Could the second main board I got is bad?

Help is much appreciated. Thank you

[nomoresonys]

Re: XBR-55X850 turns on but no pic no 12v on t-con

What do you mean by pairing? you mean you tried updating firmware? try to follow the update procedure EXACTLY how it says on the sony site, most failures are due to preparing the usb drive incorrectly or improper procedure and occasionally you can get a corrupt download of the firmware.