Something is causing the LCD to not be initialized. It could be a bad solder joint,
something shorted, a defective LCD, a defective component, a component installed
wrong, or in the wrong place. It could even be bad power.
Detailed analysis of what does work versus what does not work is suggested. This
would involve as much testing as you have test equipment to perform. A chart of
what tests you have performed could help avoid repeating the same tests later.
Electronics circuits that fail require a well thought out procedure to determine what
works and what does not work. Sometimes it can be even more involved than was
the original design.
I would start by using the schematic to locate all places where power is fed to a
component and document the power at each location. Next check the voltage
at each pin of the LCD to insure that each lead that should be getting data is
getting data during the initialization phase. An oscilloscope is useful here, but
a DVM can also be used to look for voltage changes to indicate that data is flowing.
It might be a waste of time and money to replace components before you have
definitely proven them to be defective.