We have a dead display here. Does anyone know where the 60 volts is generated on the VFD? Is it internal or some from something on the display board? It is missing from this particular display.

Stu

From what I remember when I last had my display board out, it is generated by a SMPS on there. It was some Maxim chip was wired to step up 12V to around 60V.

Well, there's a MAX770 on the board, but it seems to max out at 15 volts according to the datasheet.

(Edit, nevermind. Other voltages are possible as well. It's late!)

Stu

What is there between the output of the MAX770 at the resistor divider and the 60 volt pins at the VFD? Anything? I'm getting 3 volts at the pins and 59.8 volts right at the divider R2. I know there is at least a 22 ohm resistor to one of the pins.

Stu

It was an open 22 ohm resistor that killed the display. Something must have shorted to the common leads on the display and fried it.

We put a temporary through hole resistor across the old surface mount one and now it's working again!

Stu

Congrats. Now there's just the memory upgrade empeg to fix.