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These display problem may sometimes caused by a faulty LCD screen module or a corrupted device flash firmware. If this problems occurred, you may need to try to replace or install a new LCD screen of the device, then try to restore or flash the device firmware again.
If all of the above does not solved the display problem on Nokia E73, you may then consider that the problem lies on a faulty hardware components on Nokia E73 PCB board.

The solution below shows the connection line paths of the LCD display circuit, which can be used for easy tracing and check up procedure on certain components or parts.

There are two display filter IC is being used on the Nokia E73 display circuit. These two filter chips may sometimes caused the problem if it become faulty or being already damaged.
You may need to replace one or both of these display filter ic to fix Nokia E73 display problem.
The solution above also includes the connection line paths from the LCD pin connector to both of the display filter ICs solder ball bumps for further tracing or troubleshooting procedures.