How to figure out the pin out of this undocumented LCD?
Driving raw LCDs is a complex business. Microchip have a good appnote on how to create an LCD driver with a PIC microcontroller, the ideas are all transferrable to other devices.

When reverse engineering devices, it's best to gain as much information as possible from a still working unit with a logic analzyer. If you have two units, you can then keep one working while you clone the driver hardware/software for your new system.

If you are lucky, your LCD may be a chip-on-glass module with a driver chip built in. By sniffing the data transactions with this, it might be possible to guess at the device.