
OI
CON DITIONS FREQU ENTLY M ISTAKEN TO TROU BLES
Noise: There are 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 part is deteriorated) and (21 an
external source of noise gives noise to the unit.
When a hi-fi unit produces an unpleasant noise, it is often judged
that the unit is faulty, but statistical records indicate that the
majority of noises produced in a hi-f i 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 out-
put noise. lf your receiver produces a noise, check according
to the following table and trace out the source of noise for
an appropriate corrective action.
The table includes the conditions that may be mistaken to
troubles of the unit.
Symptom Suspected Source of Noise Diagonosis and Remedy
o
o
o
a
o
ID
o
.!
c
o
.9
J
c
o
I
3
Continuous or intermittent
noise like jijjij ot zzzzzz, . Statics or listening.
a Flourescent lamp, motor, or thermostat
may be used in house or in the vicinitv
of the house.
ln many cases, it is very difficult to remove the source
of noise. ln order to increase 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
program .
a Poor fluoresent lamp, motor, or electric
heater may be used in house or near the
hou se.
Fleversing the llne plug may occasionally alleviate this
noise problem, Usually it is very difficult to eliminate
the noise.
Hissing sound noise in AM
(medium wave) reception. a The frequency of an adjacent station is
interfering with that of the station being
tuned in (1okHz beat interference).
. TV set is on in the same house where
the receiver.
lmpossible to remove such interference. lf the cause of
such noise is in the TV set, increase the distance
between the TV set and receiver.
Static noise in FM reception
(in particular, when auto-
mobiles run close to the
house).
a White noises generated from automobile
engines.
a R adio f requepcy sewing mach ine or weld-
ing 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 function. Set up an outdoor FM
antenna having many reflector elements.
o
o
o
cc
o
.g
s
o-
c
o
3
Reception of FM stereo
program contains more
noise than FM mono
proqram.
a Note that the service area covered by an
FM stereo broadcast is about 50 %
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-antenna.
Hum or buzz, When
switched to radio reception,
the noise will disappear,
a Poor connection of shielded wire (a).
a Jack connection is loose. (b)
a Line cord or fluorescent lamp is near the
shielded wire, (c)
o Poor gyounding. (d)
a HAM 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.
Treble is not clear.
. Stylus is worn out. (a)
. Record is worn out. (b)
. Dust adheres to stylus. (c)
.lmproper mounting of stylus. (d)
a Stylus pressure is not proper. (e)
. The TREBLE sound tevel is too high.
Check (a) through (e) and correct the condition,
Lower the TREBLE level,
Lower the TREBLE level,
Further, watch the following conditions: These are also apt to be mistaken to troubles of the unit.
Symptom Suspected Source of Noise Diagonosis and Remedv
Power is not turned on al-
though the power switch is
set to ON.
o Fuse is blown. (a) '
. Line plug is loo*. (b) Check (a) and (b) and correct the condition.
ln playing a record, increas-
ing the volume will cause
howling.
a Distance between the record plaver and
the speakers is too short.
a The place on which the record player or
speakers is unstable.
Change the distance or rearrange the installation posit-
ions of the unit and speakers. (lnstallinq the .ecord
plaver on a firm, solid stand may alleviate this problem.)
Do not eR+t€nce the BASS sound level excessively.