I don't know anything about selenium cells either but I will relate my
one experience. My very first camera (I still have it) is a Petri 7s
with 45mm f/2.8 lens which is surrounded by a selenium cell inside the
filter threads. <http://www.pbase.com/equipment/image/61731065>
I bought the Petri in early 1962 and in July or August 1964 the meter
stopped working after I left it in the trunk of a friend's car in the
hot, Texas summer sun... probable cause but I don't know that's what
actually caused the failure. I continued to use the camera with a hand
held Bewi selenium meter until I got my first SLR (Miranda GT) in 1968.
(The Bewi meter is long gone, no idea what happened to it)
Then, about 5 years ago, I stumbled onto a junker Petri 7s for $5. It
was basically the same camera but was obviously a bit later model since
the ASA scale went to 800 instead of 400. Since the lens and selenium
bits seemed to be intact and I had previously determined that the
galvanometer in my camera was good I bought the junker and transferred
the selenium cell and the ISO setting ring/potentiometer to my camera.
I determined that the selenium cell was still working but that the meter
was about 1 stop off. I assumed that was due to different resistors to
accommodate the ISO 800 max and that I needed to measure them and swap
in some new ones. Then I lost interest and the camera is still setting
in a box partially disassembled.
The point of all this is that after roughly 40 years the other camera
still had a working piece of selenium cell.
Chuck Norcutt
David Carter wrote:
> Darin,
>
> I'm trying to recall what little I discovered about Selenium cell
> meters. Several years ago. FWIW I'm not a camera repairman, I'm barely
> able to strip & clean simple lenses.
>
> I remember reading one article that stated. A design or workmanship
> problem was the solder joint, not being as good in some cameras as
> others. And leaving them exposed constantly to light, isn't a bright idea.
>
> Sorry I don't know how quickly they die. It seems like the answer could
> be as variable as "how long is a piece of string". There are to many
> unknown & unforseen issues to work through.
>
> One that did occur to me. Was the quality of the selenium. Not to
> mention the quantity, required to work the camera.
>
> David
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