820-3115 no video

[MDY]

820-3115 board. Liquid damage I repaired 1 month ago and now back here again. Problem was arroun lvds connector. I replaced it again but no video, no backlight. I miss PP3V3_LCDVDD_SW
I checked U9000 and no short there. I also miss LCD_IG_PWR_EN

Mouse is on

 

[dukefawks]

LCD not recognized. Try a known good LCD assembly and check pins 4 6 and 7 of LCD connector. Also check that SMC_LID is high.

 

[MDY]

Sorry if I dont understand you, but screen to be recognized I should have at least one uncondition present power supplay to the screen. Isnot that LCDVDD?

 

[dukefawks]

pin 4 supplies 3V to the EEPROM in the LCD that has the EDID information for the system to "see" the LCD. So pins 4 6 7 should always have 3V.

 

[MDY]

You are always right. L9008 - 80 ohm
Will replace tomorrow and test. This is the problem I think.

 

[dukefawks]

Backlight will be uneven. Put some wirer from connector to the resistor in the return lines.

 

[MDY]

Backlight is off again. When I power the board screen blink in white and then became black again. 20 seg later blink again and sometumes backlight appear for 3-6 seg only. After 40seg I noted thet LP got hot. Any thing suspect? I already replaced LP8550