ZWD 1270S has an error code 90 what does this mean?

E90 is a communication error between the main pcb and the display pcb.Check the blue wiring loom that goes from the main pcb to the display pcb.normally it is a bad/loose connection on the display pcb end.clean pcb tracks and tighten the blue connector loom pins up and hopefully it will work.if it doesn't solve the problem then you could have a faulty display pcb or main pcb.

ck
May 2009