Any cure for fading FL displays ?

[Adrian Glaubitz]

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:

<http://en.wikipedia.org/wiki/Vacuum_fluorescent_display>

Thanks !

Adrian

 

[Michael Kennedy]

"Adrian Glaubitz" <glaubitz@physik.fu-berlin.de> wrote in message
news:72nqeaFqt82eU1@mid.uni-berlin.de...

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:

http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

Thanks !

Adrian

Read this it might help.

<http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/c2452c625501719a/fef051018cbb4e03?hl=en&ie=UTF-8&q=VFD+dim+group:sci.electronics.repair#>

And on the Sci.Electronics.Repair FAQ

http://www.repairfaq.org/REPAIR/F_vcrfaq7.html#VCRFAQ_008

Mike

 

[Clint Sharp]

In message <72nqeaFqt82eU1@mid.uni-berlin.de>, Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> writes

Hello,
Hi, snip.
So, I wonder whether there is anything one can do to rejuvenate those
vaccuum fluorescent diplays:
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..

http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

Thanks !

Adrian

--
Clint Sharp

 

[GregS]

In article <1CzGeuCDV7xJFwBN@clintsmc.demon.co.uk>, Clint Sharp <clint@clintsmc.demon.co.uk> wrote:

In message <72nqeaFqt82eU1@mid.uni-berlin.de>, Adrian Glaubitz
glaubitz@physik.fu-berlin.de> writes
Hello,
Hi, snip.
So, I wonder whether there is anything one can do to rejuvenate those
vaccuum fluorescent diplays:
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..
http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

Thanks !

Adrian

You can also remove the filter

 

[Arfa Daily]

"Adrian Glaubitz" <glaubitz@physik.fu-berlin.de> wrote in message
news:72nqeaFqt82eU1@mid.uni-berlin.de...

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:

http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

Thanks !

Adrian

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