Hello all,
An odd way to repair something story. I have an old (1983) Canon desk top calculator with a VFD. (Model CP-1230D) The display is 12 digits and the digits that DON'T get used very often are quite a bit dimmer. (Unfortunately, I don't get into the Thousand dollar range that often.)
One brand of equipment that I service has had similar problems with some of their VFD's. Their cure is to update the unit with a version of software that allows you to press a few keys and light up the entire display, and leave it that way for 24 hours. I was very skeptical the first time I did this, but within 5-10 minutes you can already see improvement!
So, I decided to try this on my calculator by typing in all eights and leaving it on over night. Much to my surprise it restored the dim segments to the same brightness as the others.
I'm not saying that this is a cure all or will work on every dim VFD, but it costs almost nothing and is simple enough to try. Please post any results if you try this.
Best regards, Tim Schwartz Bristol Electronics