820-3115 LCD_IG_PWR_EN is missing

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Hello,
Would any one be so kind to help with this issue that i'm facing, please.
A logicboard 820-3115 has green light on the charger and it turns on but there is no video.
I measured U9000 and LCD_IG_PWR_EN on pin 1 is missing. pin 2 and 3 have 3,42.
pin 4 5 and 6 are 0.
(Sorry for my bad English)

 

[2informaticos]

Check first for USB activity; no reason to search video on a non-working board...

Post voltage for L7510/20.

 

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Thanks for your replay
the voltage on L7510 is 0.84v and L7520 is 0.83 and L7550 is 0.34
and the usb muse turns on

 

[2informaticos]

So the board boots.
Check voltage on J9000, pins 4, 6, 7.

 

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all of them 4, 6 and 7 have 3,39v
(cable is not connected)

 

[2informaticos]

You need to connect LCD when measure J9000.
Check if L9004/08/80 are all OK.

Next, check resistance to ground on all LVDS_IG_A_DATA_ lines.

 

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The L9004, L9008, L9080 are all ok.
and the resistance to ground on pin 8,9,11,12,14, 15 and 17 are between 1.2 and 2 ohms

 

[2informaticos]

???
Did you measure diode mode on powered board???
Please, measure in correct way...

 

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Dear sir,
I measured them again on powered board with connected cable,
all of these pins 8,9,11,12,14, 15 and 17 are 1.01 in diode mode

 

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and pp3v3_LCDVDD_SW on diode mode shows 0.071

 

[2informaticos]

Never-ever measure diode mode on powered board!!!

 

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Dear I did the measurement again.
pin 8,9,11,12,14,15,17 are 0.64 in diode mode

 

[2informaticos]

Try known good LCD assembly (screen + video cable).

 

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with LCD assembly all the pins 8,9,11,12,14,15,17 are 0.42.

 

[2informaticos]

"Try known good LCD assembly (screen + video cable)."
Means check if get image and backlight...

 

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PP3V3_S0_LCD_F on pin 4 is 3.4
LVDS_DDC_CLK on pin 6 is 3.4
LVDS_DDC_DATA on pin 7 is 3,4
on backlight fuse i have 12,4
LCD_PWR_EN is missing

 

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PP3V3_S0_LCD_F on pin 4 is 3.4
LVDS_DDC_CLK on pin 6 is 3.4
LVDS_DDC_DATA on pin 7 is 3,4
on backlight fuse i have 12,4
LCD_PWR_EN is missing

 

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PP3V3_S0_LCD_F on pin 4 is 3.4
LVDS_DDC_CLK on pin 6 is 3.4
LVDS_DDC_DATA on pin 7 is 3,4
on backlight fuse i have 12,4
LCD_PWR_EN is missing

 

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Sorry accidentally post it 3 times

 

[2informaticos]

Did you measure with known good LCD connected?
Do you get image and only missing backlight?