VFD and Keypad re-use

I eventually traced out the PSU for the DVD player and worked out a power supply for the circuit.

It requires two rails, a -20v grid rail, and a +2.5v heater rail, both DC.  The heater -ve needs to be referenced to the grid -ve via a zener diode.

Here is the power supply arrangement shown with a +20v supply for the grid (+ve grounded since we actually want a -ve supply), and a 2.5v supply for the heater.

Here is a picture of the VFD outside the DVD player using external power supplies, and also a basic schematic of how to link the two rails.

For implementation into a project I am thinking of using a 20v laptop power supply, with a DC-DC converter for 3.3v logic, then an LDO or simple diode for the 2.5v heater rail.

Note that DC heater drives are usually reserved for VFDs that are small, and that are custom designed to cope with a DC heater power supply.  This page from Futaba explains this further:

http://www.futaba.co.jp/en/display/vfdinfo/vinfo_kudo_1.html