acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd | |
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| Mohamed Kamel 10/04/2014 14:05 |
Hi!
acer aspire 7750 display is ok on external monitor, but dim on led lcd. Tested with another working lcd, always dim display. Main Voltages measured on JLVDS1 connector pins : +INVPWR_B+ : 21V Local_Dim_R : 0.8 to 1.1V INVTPWM : 3.6V +3VS : ok +LCDVDD : 3.6v +5VS : ok But BKOFF# : 0V ??? issued from EC kb930QF BKOFF# resistance to ground measured about 4 ohms ?? I guess that BKOFF# should be around 3v to enable backlight. Do I have to replace the EC to get BKOFF# high and enable backlight ? Please advise further. Thank you |
| SBA 10/04/2014 21:02 |
There is very easy way - desoldering BKOFF# pin kb930. After this, you can decide to change kb930, or try to find something else. |
| Mohamed Kamel 11/04/2014 01:59 |
I do agree with you. It's the easiest and most reliable way, though I often avoid handling pins of large chips singly as they are prone to break easily.
I'll go on and feed back. thank you |
| Mohamed Kamel 25/04/2014 21:51 |
Wish to share members, how I solved the acer aspire 7750 dim display issue.
As BKOFF# signal was low, and resistance to ground about 4 ohms, I lifted BKOFF# pin of kb930 as suggested by "SBA", and it's resistance to ground went high, but 3.3V was always absent. I traced from BKOFF# pin of JLVDS1 back to EC kb930 & found R342 is missing, fixed a new one, BKOFF# went then high and display came |
