I followed Kjells advice below and removed the filter in front of the
display on my FT990 and sure enough, the display has plenty of brilliance.
Two notches up on the brightness control is plenty enough.
Actually, I think that the filter itself has changed over the years and
degraded to the point where it is now letting less and less light through.
When I hold it up against the window there is not much daylight coming
through it at all.
A bit hesitant to cut the filter like Kjell has done, I will try making a
new one on a colour laser printer using plastic film. I can then experiment
with with different grades of fill on the plastic film, and different
colour shades. As it all sits behind a very sturdy plastic front panel I
see no problem to use the somewhat more flimsy film.
Anyhow, my suspicion that the acutal fluorescent tube had deteriorated
badly proved to be wrong, this in itself is the best news I could get.
73/Peter SM2CEW
At 23:29 2005-09-10 , you wrote:
>Hej Peter,
>
>My FT990 developed the same problem after years of 24/7 duty as
>a Pactor PBBS. But don't worry, there's still a lot of light
>left in there! The light is emitted by a vacuum fluorescent
>display, which by nature is greenish blue. In front of it there
>is a very dense filter, which only allows the very small
>fraction of the total light, which falls in the orange part of
>the VFD spectrum, to pass.
>
>I have removed the orange filter and for the last three or four
>years I have been running my greenish blue display in the first
>or second brightness position.
>
>First a warning: I'm only describing what I did to my own radio
>and cannot be held responsible whatsoever for any damage caused
>by a person trying to use the following as a work description,
>which is not intended to be. Further, any warranty left in that
>old box will certainly be void.
>
>1. The plastic decoration strip directly below the display
>window can be removed. I did so by carefully lifting it at the
>end to the left of the YAESU badge and sliding it approximately
>3 mm to the left.
>
>2. I removed the display window by unscrewing the little screws
>which now became visible. This allowed me to take out the
>escutcheon, which contains the orange filter.
>
>3. The next operation required considerable patience and care
>since the escutcheon material is quite brittle when worked upon.
>Using hobby knife and a straight ruler I cut through the
>escutcheon sheet around the orange filter part, until it could
>be peeled out.
>
>4. After restoring the escutcheon, display window, screws and
>decoration strips back to their positions, I was quite happy
>with the resulting brightness. Since the "works" of the VFD may
>be visible during some ambient light conditions, I have
>considered adding a light gray filter, but it has not annoyed me
>enough to make me go to the photo shop.
>
>So Peter, that's how my FT-990 got its aurora-tinted display. I
>hope that life up north is good.
>
>73,
>Kjell, PB3SM - SM6CPI
>
>
>
>
>
>-----Original Message-----
>From: yaesu-bounces@contesting.com
>[mailto:yaesu-bounces@contesting.com]On Behalf Of Peter Sundberg
>Sent: September 10, 2005 16:22
>To: yaesu@contesting.com
>Subject: [Yaesu] FT990 display
>
>
>Now having a new MkV I realize how dim the display is on my old
>FT990. Is
>there a way to increase display brightness on that old machine?
>Is it doomed to eventually fade out completely or is it just by
>comparison
>it looks dim?
>
>I have not had the 990 since it was new, so I can't really tell
>if it
>slowly fades out or if it's always been like this. I understand
>the
>principal difference between the MP display and the 990, but I
>wouldn'd
>mind the 990 to "shine" a bit more.. it's too good a radio to
>throw on the
>junkpile just yet..
>
>:-)
>
>73/Peter SM2CEW
>
>
>
>
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>
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