(347) 552-2258 [email protected]

820-00165: No backlight. PPHV_S0SW_LCDBKLT 24v and slowly drops

M

macRepairAmb

Member
Have another board with no backlight. Once turned on, the backlight flickers on and then off. PPHV_S0SW_LCDBKLT starts at about 24v and slowly drops to about 17v. With J9500 cable unplugged i get backlight. So replaced both the cable and the io board with the same result. I've checked for corrosion and found none. Also, the charge light isn't coming on with both io boards used.
 
2informaticos

2informaticos

Administrator
Staff member
"SMC_LID is back to 3.4v and 1.4v with it unplugged"
Should I read "plugged" instead???

If yes, then you have a problem with Hall sensor on the LIO board.
Usually corrosion on trace, or resistor; sometime on the LIO flex/connector.

Do you get image/backlight without LIO flex connected?
When SMC_LID stays high...
 
M

macRepairAmb

Member
Sorry, yeah meant 1.4v when LIO is plugged in.

I thought it was the LIO board, but i tried 3 different LIO boards and all 3 LIO boards are doing the same thing on this board and work just fine on known good board.

Yes, i get image and backlight without the LIO flex connected and the SMC_LID also is 3.4v at this point as well.

I also just noticed the SYS_ONEWIRE is reading 1.4v both with the LIO flex connected and unconnected.
 
M

macRepairAmb

Member
So decided to look closely again at the LIO flex, and sure enough pins 21 and 23 on J9500 were corroded. Replaced connector and that fixed it. Thanks once again for the assist.
 
You must log in or register to reply here.
Top