Thank you for all your help and patience
I have double checked every single wire and they all measure good and are connected to what I believe to be the correct pins.
LCD - Arduino
1 - Ground
2 - +5V supply
3 - Wiper of the external potentiometer for LCD contrast (about -3,5V gave the best contrast)
4 - 16/A2
5 - 17/A3
6 - 18/A4
7 - 8
8 - 9
9 - 10
10 - 11
11 - 4
12 - 5
13 - 6
14 - 7
15 - 14/A0
16 - 15/A1
17 - Not connected (I have tried 19/A5 with u8g2 and RESET but it makes no difference)
18 - One side of the external potentiometer
LED backlight is connected to a 9V battery and a Supertex CL2 20mA constant current LED driver
The LCD display board is rev. 2.0 from 2002, but the data sheet is from 2004 so I can not be 100% sure all specs on my old display are the same.
fdcg12864b.pdf (43.5 KB)
FDCG12864B-NSWBBW-51XN.pdf (184 KB)