LCD Screen Pressing Maintenance Operation Guide
Tool Preparation
Pulse screen press machine (recommended to choose adjustable temperature type)
Vacuum suction cup group (suitable for various screens of different sizes)
Dust free cloth, optical grade AB adhesive
Multimeter, Logic Board Tester
Microscope (20 times or more) is used to observe cable interfaces.
Fault diagnosis process
1. Preliminary judgment: The screen body has been tested through the universal drive board
If the display is normal, the fault is on the motherboard
If there are horizontal/vertical/blurred lines on the logic board, it is necessary to focus on checking the screen body wiring.
2. Common types of faults:
Fault symptoms/possible causes
Localized bright lines/COF chip virtual soldering
Half no display/Y-axis drive circuit damaged
Full screen flicker/VCOM voltage abnormality
Constant color spots/liquid crystal layer leakage
3、 Screen pressing operation steps
Screen separation:
Use a pulse screen press to remove the problematic TAB/COF and re press it together
Screen separation vacuum suction cup slowly separates the glass and liquid crystal layer
to avoid violent pulling that may cause ITO circuit breakage
Cable repair:
Under the microscope, check the oxidation status of the FPC wiring gold fingers.
After cleaning with an ultrasonic cleaning machine, re press the wiring interface
and focus on inspecting the 21V power supply chip of the BOE screen.
Reorganization and encapsulation:
Evenly apply optical adhesive (thickness 0.3mm) in a vacuum environment to
eliminate bubbles, hold pressure for 15 minutes, and cure at a constant temperature
of 80 ° C for 2 hours.
4、 Precautions
1. Risk control
Avoid using metal tools to directly contact the circuit board
After repair, a 72 hour aging test is required
Thoroughly dry the water screen cloud before powering on.
2. Handling of special models:
LG screen: Y-axis damage can disconnect power supply on the faulty side
Samsung screen: half delay needs to be removed corresponding to Y-axis drive
BOE screen: VGH/GL voltage is prone to abnormalities
