[SOLVED]280-3437 no backlight.

[MDY]

280-3437 no backlight. Can see blinking folder

LCD backlight - 8.57V

Enable pin - 2.84V
PWM - 1.47V
SDA and SCL - 3.3V
All 6 return lines - 0.630 with red to ground

Already replaced 2 times LP8550 and tried 3 different working screens. Have no more ideas.

 

[aprendiz]

Did you read the sticky??
Dido you check the feedback trace??

 

[MDY]

As I said

All 6 return lines - 0.630 with red to ground

In this board the resistors are just next to the connector. And 0.630 means they go to the LP8550. Also go to lvds connector.

 

[dukefawks]

As he said, check the feedback trace to ball A5, read the sticky topic.

 

[MDY]

Yes, it was A5 ball bad trace. Now have backlight. Had do remove the chip to run a wire. Do you run the wire without removing the chip? And also this happend on Pro too?

 

[dukefawks]

There is no magic. On some board there is a small bit of trace you can scrape clean next to the chip on most boards you need to pull the chip