Futuba VFD replacement?

[PaulAm]

I'm repairing an old HP DesignJet plotter and I have an unreadably dim VFD display.  I had a used replacement, which is at least readable, but it's still not as bright as I'd like.

This is a Futuba US202SD01A display which is a 2x20 VFD with the associated support circuitry and uses a 5 pin serial interface connector.  Apparently, somebody has reverse engineered the protocol and there's a library available to drive the display from an Arduino, but I'm coming up blank on a display replacement.

Anyone have a NOS unit gathering dust?  Maybe just the VFD?  Doesn't look like fun to remove and replace it, but it's doable.

[BradC]

I replaced mine with a 2x20 LCD but there are "issues" with special characters and it most certainly won't work with anything other than English. That Futaba display has a plethora of special characters and you only have space for 8 in the LCD. I toyed with a dynamic loader to load them as needed but it was more hassle than it was worth.

I reverse engineered the protocol and wrote a converter for the Parallax Propeller. That was years ago now, I'll have a look and see if I can find the code. It's a funky protocol.mfrom memory it starts out 8 bit and then switches to a 10 bit stream after boot up.

I had no luck sourcing credible vfd replacements.

[james_s]

2x20 VFDs are fairly standard, you may be able to transfer the glass from a similar display to the board on yours but beware some of the modern ones are "chip on glass" with an internal driver.

You can also rejuvenate VFDs, have a look online. Essentially you boost the filament voltage to burn off contaminates and expose a new layer of emissive oxides, similar to rejuvenating tired CRTs. VFDs are essentially inside-out flood gun CRTs.

[PaulAm]

Well some more looking and I found some NOS Futuba NA202SD08FA displays which appear to use the same display and the same driver chips.  I have a couple on order and we'll see if they work out.

This display has all the leads on one side.

An alternative would be to get a current display and put in a protocol converter, but that's more work than I really want to do.  Transferring the display will be bad enough.

[james_s]

Have you tried rejuvenating it? I found the page I was thinking about, turns out it's right here on eevblog.

https://www.eevblog.com/forum/chat/vacuum-fluorescent-display-rejuvenation/

[PaulAm]

I'll give it a shot and see what happens; it might be good enough.