Hello,
I have an older audio timer, AKAI DT-320 (around 1983), whose FL display has aged over the years of usage and become faint. Compared to the tuner and tapedeck of the stereo (same year/series) it is tremendously darker which I think is related to the fact that the audio timer display is always powered on while the tuner/tape ones only when they are acutally in use.
So, I wonder whether there is anything one can do to rejuvenate those vaccuum fluorescent diplays:
Thanks !
Adrian
Read this it might help.
And on the Sci.Electronics.Repair FAQ
Mike
In message , Adrian Glaubitz writes
Hi, snip.
Clean it. Seriously, when I used to repair VCRs they almost always had VFD displays and the amount of crud they attract is amazing. Simply removing the accumulated dust from the glass and the plastic bezel often brought comments from the owners of how wonderful the new display was and had we swapped the machine for a new one..
-- Clint Sharp
You can also remove the filter
Although a dark VFD can often be down to it being worn out, it can just as often be due to the supply voltage having dropped. This will normally be on the order of -29v (that's negative 29) with respect to chassis. This voltage is often derived from a crude voltage multiplier formed with diodes and electrolytics, which are being subjected to large levels of AC across them. This can lead to them drying out, and their ESR going out of the window. The upshot of this is that the supply voltage drops, and the display becomes dim. The filament is usually 'floated' on this supply, so the filament pins (one or two at each end of the display, separated from the rest of the pins by one space), is a good place to check for this voltage. That's one meter lead to chassis, and the other to any one of those pins. See a voltage lower than about neg 25, and the chances are that you have a supply fault being caused by a bad cap.
Arfa
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