A1708 EMC 3165 - 820 00840 A - Intermittent no Screen / Backlight

LCDR2

Member
Hello

Client has brought in laptop with their son saying there is no screen.

I get the laptop in the bench and open lid... perfect video. This morning nothing on display for about five minutes, I go away for a bit to find a torch to see if it's just no back-light and the laptop is on again and running.

Given the intermittent nature of the issue how do I start diagnosing ?

Are there any known / common problems with this laptop ? I've head of the stage light issue but not sure if it applies here.

Cheers

James

PS Will update post if I determine if it's backlight / video / no power.
 

2informaticos

Administrator
Staff member
Check LID_OPEN and SMC_LID_LEFT/RIGHT signals, when the problem appears.
Post BKLT_EN_R level.

You should try known good compatible LCD assembly; to discard flex problem...
 

LCDR2

Member
LID_OPEN 3.5v
SMC_LID LEFT 3.5v
SMC LID Righ 160mv
HALL_SENSOR_RIGHT 160mv (audio flex not connected so I assume this is the reason for low value?)
BKLT_EN R 2mv
 

LCDR2

Member
BKLT_EN_R sometimes seems to drop to 0v with corresponding drop on backlight circuit from 45v to 12v

I'll test with another screen, sorry. I don't have them lying around yet like you guys do for testing!
 
Top