ISO Selenium Rectifiers

[Glen Zook]

Selenium rectifiers are a very definite health
hazzard.  When overheated, they produce a very toxic
gas that can cause severe failure of the human kidney.

Back when selenium rectifiers were very common in
televsion sets a number of fire-fighters had permanent
damage to their kidneys due to breathing the fumes
from fires within television repair shops, sales
facilities, etc.  In fact, it became "standard
operating procedure" not to enter any building that
there was a possibility of televison sets being
located unless proper breathing apparatus was used.

Now, a single set in a residence was not very likely
to cause any problems.  But, when there were several
sets located, and the building was on fire, firemen
did not enter the premysis.

I "learned" this when a freshman in high school when I
was a member of a local "team" that was sponsored by
the fire department.  Although we didn't really fight
any fires (but we did some "search and rescue" work in
the area), we were actually trained in how to use
various fire apparatus, safety precautions, etc.

The possibility of a selenium rectifier overheating
and giving off the problematic fumes is a definite
factor when using them in various equipment.  Silicon
rectifiers are MUCH smaller and have MUCH higher
current specifications than selenium rectifiers.
However, silicon diodes have considerably less voltage
drop across them than selenium.  As such, you
sometimes have to add several ohms in series to get
the same effective voltage (the silicon diodes put out
a higher voltage).  This is just like when replacing
tube type rectifiers sometimes you have to put like 50
ohms in series to get the same output voltage.

Don't replace selenium rectifiers with germanium
diodes!  Germanium diodes can't really take anywhere
near the current that either selenium or silicon
diodes can take.

Glen, K9STH


--- "J. Forster" <jfor at QUIK.COM> wrote:

Does anyone know of either a source for NOS
Selenium-Oxide rectifiers or someone who rebuilds
them?

Obviously they could be replaced with siliconies or
geraniums, but I'd rather not go that route.

=====
Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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