Realistic STA-21 - Trouble Shoot!Ng

5.
TROUBLE
SHOOT!NG
Symptom
Cause/Remedy
1) No
output. 1) Faulty
AC
power
cord.
{<
Replace
the cord.
2) Defective
power
switch.
x
Replace
the switch.
3) Broken wire in
the
power
transformer.
*
Replace
the transformer.
2)
Pilot
lamp
does not
light.
1) Broken
lamp.
x
Replace the lamp.
2) Open in the
power
transformer
tertiary winding.
{<
Replace the
power
transformer.
3)
Pilot
lamp lights
but no
speaker ouptut.
1) Defective capacitor
C326or
C327.
*
Replace the defective
capacitor{s).
2) Defective
diode D
301, 302, 303 or 304.
x
Replace the
defective diode(s).
3)
Defect in
the
power
transformer
secondary winding.
*
Beplace the
power
transformer.
4) Blows fuse.
1) Defective doide D
301-304 in the rectifier
circuit.
x
Replace
the defective diode(s).
2) Short-circuit in the rectifier
circuit.
x
Remove
the short.
3) Short-circuit
in
power
transistor
circuitry TR
311-314.
*
Repair
circuit and,/or Replace
the defective
transistor.
5-1)
No
output
one channel with
VOLUME
at maximum and
BALANCE
at center,
when a test
signal is
applied
to the
terminal
of
non-operating
channel of
the
BALANCE
control R 249.
1) Defective
transistor TR 205, 206
or
TR
301-314.
x
Replace the
defective
transistor(s).
2)
Defective resistor
or capacitor
of TONE or MAIN AMP
circuit.
*
Replace
the
defective
part(s).
5-2) No
output when
a
test signal
is
applied
to the input
terminals.
1) Defective transistor,
resistor
or capacitor of PRE AMP
circuit.
*<
Replace the defective
part(s).
2) Defective MONO/STEBEO or TAPE MONITOR switch.
x
Replace or repair the
switch(es).
3) Defective Selector switch,
*
Replace the
Selector switch.
6) Speaker works normally but headphone
does not work.
1) Defective R
zl01
(left)
or
R
4O2
(right).
x
Change
it.
7) All the inputs
work normally except
"AUX"
input.
1) Poor
contact
in
"AUX"
input
jack.
x
Replace
or repair it.
2) Defective resistor
R 501, 502,
503 or 5(X.
*
Replace it.
3)
Poor
contact in selector
switch.
*
Repair
or replace the switch.
8) "PHONO" input no operative. 1) Poor
contact
in "PHONO"
input
jack.
x
Repair
or replace it.
2)
Faulty selector
switch.
x
Repair
or replace the switch.
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