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CONDITIONS FREOUENTLY
MISTAKEN
FOR
MALFUNCTION
Noise:
There
zlre a
variety of
noises
relating to the
operation
of a
hi-fi
unit.
These are
generally
divided
into two
types; (1) the
unit
is faulty
(a
transistor
or
paft
has deteriorated) and
(2\
an
external
source is
adding
to the unit.
When
a
hi-fi unit
produces an unpleasant noise,
it
is
often
assumed
that the unit
is
faulty, but statistical
records indicate
that
the majority
of
noises
pro-
WATCH FOR
THE
FOLLOWING CONDITIONS; THESE ARE ALSO APT TO BE MISTAKEN
FOR
MALFUNCTION-
duced
in hi-fi
acoustic
units result from
external
sources
of noise:
Due
to the
inherent
high
sensitivity and
the high fidelity in
reproduction,
the unit
amplifies
and
reproduces
extraneous
noises,
however small,
into definite output
noise.
If
your
receiver produces a noise, check according
to
the following table and trace out the
sowce of
noise
for
the appropriate corrective action.
SYMPTOM
SUSPECTED SOURCE
OF
NOISE
DIAGNOSIS
AND
REMEDY
a
F
a
O
o
o
E
co
o
F
(9
z
2
lll
F
@
=
z
uJ
I
=
Conti
nuous
or intermittent
noise
like
jjjjjj
or
zzzzzz.
oStatic
(lightning)
o
Fluorescent
lamp,
motor,
or
thermostat
may
be
in
use
in
house
or
in
the
vicinity
of
the
house.
ln
many
cases,
it
is
very
dif
f
icult
to
remove
the
source
of
noise.
ln
order
to
make
the
radio
input
larger than
the
noise
level,
set up
a
good
outdoor
antenna and
make
a
complete grounding.
When a
station
is
tuned
in,
hum
is
mixed
in
the
pro-
gram.
oPoor
fluorescent
lamp,
motor
or
electric
heater may
be
in
use
in
house
or
near the
house.
Reversing
the line plug
may occasionally alleviate
this
noise
problem. Usually
it
is very diff
icult
to
eliminate
the
noise.
Static
noise
(in
particular,
when
automobi
les
run
close
to
the
house).
oWhite noise
generated
from
automobile
engi
nes.
oRadio frequency
sewing machine or welding
machine being
used near
your
house.
ln
an area surrounded
by hills or
high buildings,
the
FM
input
signals are
very weak" Thus
the
noise
limiter
in
the
circuit
loses
its
f
unction.
Set up an FM
outdoor
antenna
having
many director
elements.
Reception
or
FM
stereo
program contains
more
noise
than FM
mono
pro-
gram.
oNote
that
the
service area
covered
by
an
FM
stereo
broadcast is
about
50%
of
that
of
a
regular mono broadcast.
lncreasing
FM input
signal may
alleviate
this problem.
Use
an
exclusive
FM
outdoor
antenna
instead
of
the
indoor T-type
antenna.
a
o
E
o
O
Irl
E
(9
z
t
J
L
z
I.JJ
r
=
Hum or buzz,
When
switched
to
radio
recep-
tion,
the
noise
disappears.
Treble
is
not
clear.
oPoor connection
of
shielded
wire
(a)
oJack
connection
is
loose.
(b)
rLine
cord
or
fluorescent lamp
is
near the
shielded
wire.
(c)
oPoor grounding
(d)
oHAM transmitting station
or
TV
transmit-
ting station
is near
your
house.
(e)
Correct
the
conditions stated
in
(a),
(b),
(c)
or
(d).
ln
case
of
(e),
report
it to
an
official
activity.
Output
tone quality
is
poor and mixed
with
noise.
.Stylus
wears
out.
(a)
oRecord
wears
out.
(b)
rDust
adheres
to
stylus.
(c)
ostylus
is
improperly mounted.
(d)
ostylus
pressure is
not proper.
(d)
oThe
TREBLE
level
is
too
high.
Check
(a)
through
(e)
and correct the
condition.
Lower the
TREBLE
level.
SYMPTOM
SUSPECTED SOURCE
OF
NOISE
DIAGNOSIS
AND
REMEDY
Power
is not
turned
on
although
the
power
switch
is
set
to
ON.
oFuse
blows.
(a)
oLine
plug
is
loose.
(b)
Check
(a)
and
(b) and
correct
the
condition.
ln
playing
a
record,
in-
creasing
the volume
causes
howling.
.Distance
between
the turntable and
the
speakers is
too
short.
oThe place on which the turntable
or
speakers are
set
is
unstable.
Change
the
distance
or
rearrange
the
installation
of
the
unit
and
speakers.
(lnstalling
the turntable
on
a firm,
sol
id stand may alleviate
this
problem.)
Do
not
enhance
the
BASS
sound level
excessiveiy.
11
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