Sony Bravia 65x900F BL On but not picture

[lmcancu]

I was watching youtube yesterday, when I paused it to go to the washroom. When I came back, the right side of the screen was showing half of the youtube channel and the left was black. I powered off/on the unit with the remote and now I have no picture whatsoever except for the bluish backlight. I did the factory reset (power + vol down), and now I when I power on I get the startup music, backlight but no picture.

I took the back cover off, and reseated all cables but unfortunately same issue. I took some voltage measurements on the main 2 headers from the power supply board and they show the correct voltages: 3.3v, 12.45v, ~38V, etc for each LED. I also removed the two ribbon cables between the t-con board and the CPU with the same result. What is my next step?

[alfatv]

Re: Sony Bravia 65x900F BL On but not picture

When you say half screen, was it sharp divide or gradual transition?
Please remove cover from t-con, that would be the next thing to try.

[EazyBone]

Re: Sony Bravia 65x900F BL On but not picture

TCON controls each half of the screen. So probably a tcon issue or panel issue. Find which side ribbon corresponds with the black side screen, as we can't see from picture and test the voltages coming from tcon to buffer boards, and search buffer boards for shorts.

Looks like picture shows you have all backlight so that's probably not the problem since we don't have a pic of the screen.

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

It was a Sharp divide I think, when I first came back from the washroom, I could only see half of the youtube screen. But then it seemed like youtube was then fully only on half the screen, but I am unsure. The measurements from the connectors on the power supply board are:

12v(LD): 12.6v
NC
GL_Ctrl: 1.6V
SENSE_GND: 3.3V
VLED_GND: 2.2mv
VLED_GND: 2.2mv
VLED_GND: 2.2mv
VLED_GND: 2.2mv
NC
VLED_VCC: 38.3v
VLED_VCC: 38.3v
VLED_VCC: 38.3v
VLED_VCC: 38.3v

BL_ON: 3.3v
GND
GND
GND: 2.9 mv
REG 12V: 12.66V
--
REG 12V: 12.65v
REG 12v: 12.65V
GND: 2.3mv
GND: 2.3mv
---
GND: 2.5mv
TCON_ON: 3.3B
TCON_VCC 12V: 12.65V


BL_ERR: 33.6mv
POWER_ON: 3.4v
STBY3.3: 3.5V
GND: 1.6mv
--
REG 12v: 12.65v
REG 12V: 12.65v
REG 12V: 12.65v
--
--
--
GND (TCON): 4.1mv
TCON VCC: 12.65

Yes I removed the cover from the t-con board

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

TCON controls each half of the screen. So probably a tcon issue or panel issue. Find which side ribbon corresponds with the black side screen, as we can't see from picture and test the voltages coming from tcon to buffer boards, and search buffer boards for shorts.

Looks like picture shows you have all backlight so that's probably not the problem since we don't have a pic of the screen.

Screen is very faint blue. I saw half the screen when the issue first appeared, after I powered off/on, I no longer had any picture just the backlight. The screen just shows a faint bluish color with the start up musinc playing.

I also tried removing the ribbon cables one at a time to see if I would get back half a screen, but no picture just the blue from the backlight

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

did you hear sound???

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

did you hear sound???

yes. The spa music after I did the factory reset

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

yes. The spa music after I did the factory reset

check T-CON fuse if there 12V at both side... if yes... then disconnect the 2 LVDS from T-CON andf feed the T-CON fuse with 12V from the PSU 12V. turn on.. see what you will have on the screen...... if the BL didn't come on at this test... use touch light to inspect the screen behavior.

if screen black no color... replace T-CON

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

check T-CON fuse if there 12V at both side... if yes... then disconnect the 2 LVDS from T-CON andf feed the T-CON fuse with 12V from the PSU 12V. turn on.. see what you will have on the screen...... if the BL didn't come on at this test... use touch light to inspect the screen behavior.

if screen black no color... replace T-CON

This fuse correct? I measured 12v on each side. And the LVDS cables are the 2 cables attached to the top right? Do I leave the third connector to the right connected as well? And how do you recommend I feed 12V from the power supply to the fuse? and which side of the fuse? Where do I get the 12v from the powe supply? I guess its from the third connector to the right?

update: I removed the 2 LVDS cables, and just verified the voltage on each side of the fuse. It was 12.65v. I don't understand how feeding 12v from the PS to the fuse will do anything since there is already 12v there?

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

no need to feed the fuse as you said you have 12V on it after you disconnect the 2 LVDS ( the 2 on the top close to fuse

yours T-CON take the 12V from the socket close to LVDS... so just turn on and see if the screen have any color pattern... if BL didnt on use light to inspect

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

no need to feed the fuse as you said you have 12V on it after you disconnect the 2 LVDS ( the 2 on the top close to fuse

yours T-CON take the 12V from the socket close to LVDS... so just turn on and see if the screen have any color pattern... if BL didnt on use light to inspect

Backlight is on but no picture with or without LVDS cables connected. I get just a blue screen as shown in the one of the pictures I posted

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

I was watching Nick's TV on YouTube and to determine if the main board was faulty, he disconnected it and then put jumpers between 3.3v STBY and Power on, and between tcon on and BL on. He then showed that the TV was doing a color pattern test and that indicated tcon, etc was good. Is this the right approach?

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

I was watching Nick's TV on YouTube and to determine if the main board was faulty, he disconnected it and then put jumpers between 3.3v STBY and Power on, and between tcon on and BL on. He then showed that the TV was doing a color pattern test and that indicated tcon, etc was good. Is this the right approach?

if this exactly true ,,, then t-con and panel and power boards are fine..... the rest MB

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

if this exactly true ,,, then t-con and panel and power boards are fine..... the rest MB

Should I use a 1k resistor instead of a straight jumper to test?

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

Should I use a 1k resistor instead of a straight jumper to test?

for people not sure or first time they do,,, will be recommend to use R 1K or less to avoid any damage if they missed with pins assignment.

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

Ok thanks! So they way I understand it, is that the 3.3v STBY pin will turn the TV on when connected to the Power on pin. Once the TV is on, it will provide 3.3v to TCON on. Then jumpering that pin with the BL On provides 3.3V to the BL so that it can turn on?

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

I tried the jumper tests: I jumpered STBY 3.3 with Power ON, and BL ON with TCON ON as shown in this video
https://www.youtube.com/watch?v=4afrEbS5mZw

But instead of BL turning on when plug in the TV, I get the 3 Red LED Blinks on the LED driver board. Anyone knows what that means? Picuture of the LED driver board attached
Note, I jumpered the pins prior to plugging the power cord. Do I need to jumper them after the power is plugged in?

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

main boards should be disconnected from T-CON and Power boards and LED driver boards

jumper put them in place then plug it in wall

[lmcancu]

Re: Sony Bravia 65x900F BL On but not picture

Yes I did exactly that. Main board was completely disconnected from all other boards. The LED driver and T-Con boards were connected to the Power Supply board.
Note to be exact: I jumpered pins 2 and 3 together (Power On and STDBY 3.3) from Header 1, and pins 1 and 13 together (BL ON and TCON_ON) from header 2.
Please see picture attached

[Diah]

Re: Sony Bravia 65x900F BL On but not picture

led driver boards need to disconnect from the boards side to avoid any short... same to LVDS at t-con need from T-con side disconnected
u can ignore BL_ON... just use power on and T-CON on.... use torch light to inspect the pattern on screen

if there nothings... you need to show us the edge puffer boards of the panel left and right.... see if there are U ribbon installed at the middle of each side