SB2 Display fading

I have an SB2 (I am not the original owner, but I have had it for 5 or 6 years) that has had the VFD develop light and dark areas. I do not remember it being this way when I purchased it, but I can't be sure. There is a general unevenness to the brightness of the display. With maybe 1/4 of the display to the right of center being particularly dark. I know that a VFD can fade over the years and the fading can be uneven. But I expected significant fading to take longer than ~10 years. I have devices with VFD that stay on 24/7 and are 20 years old and they still look fine. But I am not familiar enough with VFDs to know if this is a problem with the display (and would require replacing) or could it be an issue with the power supply driving the VFD? I will add a picture tonight to show what it is doing.

I have read the display is a Noritake MN32032A, but I am not sure they are still available. Thanks for any input.