I purchased a BigTree Tech LCD ? And found that the connectors were laid out on the mother board is the opposite key direction as my MLCD2004.2
As you can see in the two images that the Key for the connectors is backwards for the two connectors.
So Purchased the Connectors and ribbon cable to make my own connectors this allowed for the correct connections to my Controller Card.
Not sure if this is the Problem you are having so will note the fact that the BigTree has a contrast control in the upper right hand corner.
I did not like my BigTree LCD as the display had bright spots that made the LCD viewing most undesirable.
Edited 2 time(s). Last edit at 12/21/2018 07:48AM by Roberts_Clif.
Computer Programmer / Electronics Technician