hello TK,
now I measured the following:
with testlcdpin rw 1: 3V36 at j5a/b and p1.27on lpcxpresso without cable and display; and with cable only (no lcd); with testlcdpin rw 0; same spots and connections 0v24
with cable and LCD connected; however, the same measurements at j5b (cable is at j5a) and p1.27; but still always 4v96 (rw 0 and rw 1) on the lcd itself. But measuring between Vss on the LCD and j5b.rw // p1.27 both with rw 0 and rw 1 gives proper voltages ie. 3v36 and 0v24. It is either the cable or the LCD itself then, is that correct? There should be something with the cable, otherwise measurements at j5b.rw = p1.27= lcd.rw, right? But why only the RW line? that does not make sense to me. I'd expect an improperly connected cable to give more problems, not on one line.
Measuring resistance between Vd (+5V) and RW pins on the lcd gives about 830R with - on vd and + on rw. Other way around is about 750k.
Should I get more flatcable and try make another cable?
Thanks for helping me so much!