Istalled the LCD and i have some serious problems.
The LCD wiring must be checked.
If removing the LCD fixes the problem, the contact problem (likely between supply and GND) is at the DSUB9 or at the LCD. I guess the LCD does not touch any conductive surface.
The easiest if we start with a brand new LCD and cable and DSUB9 female, and the defective LCD-cable must be tested on the table.