Re: Sony Bravia KDL-40EX720 no backlight
Measurements:
CN1002: off/on
LD_ERR 0/0V something moving around 0 Volts
LED_ON 0.1/3.3V
GL_CTRL 0.7/0.0V
CN1003: off/on
1-PWM1 0/3V goes up slowly from 0V to 3.0V
2-PWM8 0/3V goes up slowly
3-PWM1 0/3V goes up slowly
4-PWM8 0/3V goes up slowly
"Also leave the probe on one of the (+OUT) and record what you read when the TV is OFF and when the TV is turned on to see if it goes up to more than 122v and then drops down to 122V or...
olegau
Member
Last Activity: 10-13-2023, 08:22 AM
Joined: 08-06-2017
Location: Melbourne
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Re: Sony Bravia KDL-40EX720 no backlight
There is sound but I cannot say about the picture because the screen is black....Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
Today I was following an advice to disconnect one after another the T-CON two flat ribbons going down to the screen. Nothing happened.Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
Pics of the TV:
General view
Connections of PCU
Connections of T-CON...Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
Yes, that is my power supply board.Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
It would be great but a lot of hassle. Maybe take measurements only the power board without the load. But it may not work because the PSU will not get feedback from other boards.Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
I checked supply 12V on conections CN6151 and CN6801. All of them 12.5V.
Power on/off 3V/0V works.Leave a comment:
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Re: Sony Bravia KDL-40EX720 no backlight
Thanks for the clarification.
So it looks LD board and screen leds are okey.
Who knows how to identify a faulty board?Last edited by olegau; 08-11-2017, 03:00 AM.Leave a comment:
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Sony Bravia KDL-40EX720 no backlight
It seems to me all work except the backlight.
The red standby and the green power on lights are stable, no flashing.
I try to identify which board or the screen is faulty.
Connections on LD board:
CN1001 (4pins)+122V each
CN1000 (5pins) four pins+28V each
What confuse me is CN1001 voltages. They suppose to be negative but it is +122V each.
I think the problem is somewhere around here.
I appreciate any opinion.... -
Re: New Members - please post your introductions here
Hi, I 'm a 60 years old. I studied electronics all my life because I love it.
I use to repair old TV and other electronics stuff 30 years ago. But I still like to fix everything myself.Leave a comment:
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