Neumann.Berlin Condenser Microohone Supplement Sheet

Neumann-Information 1
88 043
I
April 1988
Re: Disassemblina and Cleanina of Neumann Condenser Microohones
The disassembli- of the microphones in amplifiers and capsule head is
described in
the operating instructions
which
are delivered
with each
microphone.
Attention:
-~-
It is by no means allowed to tauch with the
finger
the contact and isolat-
ing elements
for
the
connection
of the capsule head. Also the other high
impedance
Parts
of the
circuit
may not be touched.
4lready minimum grease
and
dirt
quantities tan diminish the isolation
figures
and Cause noise
voltages.
Cleaning the microphone amplifier:
- -
Existing dirt on components and contacts tan be removed by means of a
soft brush using
a detergent
on the basis of
Freon, Kaltron or
Frigen.
Microphone capsules:
-
The microphone capsules of U 89 i, TLM 170 i and the KM . . . miniature micro-
phones
are
constructed in a way that the total surface is connected to
0 Volt.
For
this
reason
these microphones
are extremely insensitive
against
dirt
and atmospheric influences and should not be cleaned.
When microphone capsules had to be constructed in a way that the isolating
areas between
the
electrodes
could be
reached
by
dirt
(the
large
double
membrane Systems of U 67, U 87 (A) i, SM 69, SM 69 fet, USM 69 i, IJ 47 fet)
after a
long
period
of
Operation
noise
voltages
may
occur. For
cleaning the
membranes the capsule has
to
be
removed from its protecting grille.
At t-he
U 67, U 87 (A) i, U 47 fet microphones the 3 mounting
screws at
the
lower
plate of the capsule head have
to
be
removed
and then the complete capsule
assembly tan be
removed from
the capsule head.
At the microphones SM 69, SM 69 fet, USM 69 i the disassembly of the protect-
ing grille is more difficult:
The black dot on the upper
part
of the
grille
(position O") has to be
removed.
Behind the opening a spring is visible, this spring has to be
pressed
back by approximately 1 mm,
the
grille
tan then slightly be lifted
at
the
front
side.
Now the
grille
has
to
be
turned
by 180°, then another
spring becomes visible which has also to be pressed backward, now the
complete
upper part
of the
grille tan carefully
be
removed.
To
prevent
the
springs
to be lost these should
also be removed.
The complete capsule
assembly tan now easily be
removed from
the
lower part
of the
grillle.
pto.
CHARLOl-TENSTRASSE 3 D-i000 BERLIN 61 POSTFACH 610469 TELEGRAMM: NEUMANNACUSTIC
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