THE EYE-TUBE IN THE GARDEN
The legend goes on...
- Winter 2003/2004
There has been much discussion over the years about the effects of UV
light on tuning eye tubes. Here are some excerpts from
rec.antique.radios+phonos that finally led to putting a 1629 to the
test back in the year 2000. It is now 2004 and the tube is still
there and re-tested occasionally.
I have a 6E5 that was new in 1962 and not used much since. There is an
that is weaker than the rest due to sunlight falling on it for
years. I fear
that intense light weakens the phosphor.
Keep them out of direct sunlight. UV light shotens the lifespan.
Mine to start is on EYE TUBES.
DO NOT EXPOSE THESE TUBES TO THE SUN OR UV RADIATION. Even a 'new' tube
destroyed in a very short time if exposed to direct sunlight. Also in
way-to-short a time if exposed to Fluorescent lamps, especially the 41K
or hotter, and a bit slower if exposed to filtered sunlight. The target
phospors are degraded.
I have experienced a NEW 1629 tube being totally erased in the course
4-hour hamfest as it was exposed to direct sunlight. It also makes no
difference whether the tube is on or off.
Eye-tubes fail less from use than from exposure to UV light. Direct
can destroy them in a very few hours. Strong fluorescent takes longer
also not good. I have some 30-year-old heavily used eyes that are just
and one 62-year old 6T5 that is also just fine and in use. I have seen
eyes fail from exposure at a single hamfest.
A more common cause of eye tube dimming seems to be a
chemical degradation of the target phosphor. Caused by long hours of
service, or a short exposure to UV (sunlight).
PERHAPS A WEEK AGO THERE WAS A THREAD ABOUT EYE TUBES BEING DAMAGED BY
EXPOSURE TO SUNLIGHT. BEING IN THE EYE TUBE BUSINESS, I HAVE A
OF THEM IN STOCK. I REMOVED A TUBE FROM ITS (DATED 1941) BOX AND
CHECKED IT IN A LATE 1930'S GE TOMBSTONE. I ESTABLISHED IN MY
REFERENCE BRILLIANCE THEN PLACED IT UPRIGHT IN A FLOWER BED IN MY FRONT
YARD. EACH EVENING SINCE I HAVE BROUGHT IT IN AND TRIED IT
FAR I HAVE TESTED IT FOUR TIMES. I CANNOT TELL THAT THE
ANY LESS THAN THE INITIAL TIME. EACH DAY HAS BEEN TOTAL SUNSHINE
ESSENTIALLY NO CLOUDS. I WILL CONTINUE FOR A FEW MORE DAYS TO SEE
AT FIVE DAYS I CAN SEE NO DIFFERENCE AND FRANKLY AT THIS POINT DO NOT
EXPECT TOO. I AGREE IT WOULD HAVE BEEN INTERESTING BUT THE ONLY
METERS I HAVE ACCESS TO ARE NOT SENSITIVE ENOUGH TO TELL THE DIFFERENCE.
I HAVE CHECKED THE OUTPUT OF THE NEW 1629 EYE TUBE DAILY FOR EIGHT DAYS.
SEVEN OF THESE DAYS HAD FULL SUN, ONE DAY HAD RAIN IN THE MORNNG, SUN IN
THE AFTERNOON. I CANNOT SEE ANY DIFFERENCE IN THE LIGHT OUTPUT AS
COMPARED TO ANOTHER NEW 1629. ON THE BASIS OF THIS TEST I WOULD
CONCLUDE THAT THE IR DAMAGE SPOKEN OF EARLIER IN OTHER POSTS WERE AS A
RESULT OF FACTORS OTHER THAN SUNLIGHT. THE TUBES USED IN THIS
BOTH JAN TYPES DATED 1941.
RICH, THE TEST I RAN WASN'T SO MUCH TO PROVE ANYTHING OTHER THAN "ONE
DAY IN THE SUN WILL KILL THEM" AS SAID BY SOMEONE WAS INCORRECT.
SATISFIED MY NEED TO KNOW THAT THIS A BUNCH OF MALARKY. I
DOUBT THAT EXPOSURE TO YEARS OF USE WILL CAUSE THEM TO GET WEAKER, EVERY
TUBE DOES. AS TO WHETHER SUNLIGHT CAUSES WEAKENING, I DON'T
I AM SURE OF IS THAT EIGHT TIMES THE SPECIFIED ONE DAY HAD NO EFFECT
NO, NO, NO IT WAS IN THE BED WITH THE NEW GUINEA IMPATIENTS.
FLOWER, DARKER LEAVES.
ITS STILL THERE. LOOKS A LITTLE STRANGE SINCE FROST KILLED THE
ITS STILL GOING.
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by Webmaster - 9 April 2004