After the thread about the 3458 display, I went back to one of those VFD that I mentioned in my earlier post. These had been used with only a few digits turned on on the first line, the rest of the display being normally turned off and only used occasionally. After several years of continuous operation, the digits that were used had lost brightness and more interestingly, the other digits had also lost brightness but also looked botched (the brightness was very uneven).
It turns out I have been using one of these old displays on a new project (it's a development job, so the unevenness does not bother me at the moment since this display will not ship). After about 2 weeks of continuous use where most of the digits are used, the display is now just about back to normal. somewhat dimmer than a new one, but the unevenness has completely disappeared. It looks like either the digits themselves, or the cathode wire, had become contaminated as a result of not being used, and a few days of operation restored their activity. Even more interesting, at the moment, I cannot detect a difference in brightness between the old digits that were on for several years and those that were not. The display is generally dimmer than a new one, but the new ones are a different part number, the original device having been discontinued, so it may also be that the new display is brighter because of process improvements by the manufacturer (something the manufacturer advertised when they introduced the new device). On this development job, most of the digits are used, and the display is constantly changing (scrolling messages). Anyhow, I thought it would be interesting to mention. Didier KO4BB _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
