This solution may possibly help fix the Sony MT11i Display light problem. This kind of problem shows a dark screen displays on the LCD because a lack of illuminating backlight LED on the back of the LCD screen.
This may happen if the phone suffered wet or water damaged, accidentally dropped by the users.
Just refer to the solution below and locate the primary components that needs to be check first.
Sony MT11i Display Light Jumper Ways – connection track
Troubleshooting hints on Sony MT11i LCD display light problem:
1. First try to replace the LCD screen display module.
2. Check the LCD pin connector, clean, re-solder it if necessary.