HD61202/HD61203 Based GLCD

I have gotten my hands on an old RAMCheck from 2000. I open it up to find it has a 486 CPU in it. But that’s not what we are here for. It also had a nice 32X128 GLCD that has both an HD61202 and HD61203 controller chips on it.

There are 20 pins on this display and I have confirmed the following pins by probing the pins while the RAMCheck is running the display.
Pin1 = 5V
Pin2 = Gnd
Pin3 = Contrast Gnd
Pin18 = Contrast 7.5V (May be negative 7.5V needed but don’t know how to get a negative voltage)
Pin19 = Backlight +5
Pin20 = Backlight Gnd

I cannot confirm any other pins. So i tried connecting it to my Arduino Nove using Pinout A as shown in the KS0108 Graphics LCD library Playground page. I’ve been through all the documentation on the page regarding the reset wire, switching pins 12 and 13 as the possible chip select pins. Even tried swapping the wires on pins 15 and 16. I have connect the contrast lines as suggested and even bypassed the Arduino’s +5 and gnd and used a 9V battery with the pot to give the required 7.5V to the contrast pins. Even reversed the positive and negative leads.

Am i missing something here or does anyone have experience running this kind of display on the Arduino that can give some suggestions?

Seems to be a Seiko G1213 LCD. See attachment for the pins…