NAD 300 Service Manual page 15

t:
Symptom
Cause
and
Remedy
6)
Same as
5 above
but
channel operates
when test signal
is
applied
as
7.
A)
Defective
transistor TR501, TR502, TR503, or
TR504.
Replace
the defective transistor.
B)
Faulty resistor R502, R504, R505, R506,
R51O
or
R512.
Replace
the
faulty
resistor.
C)
Faulty capacitor C501 or C505.
Replace
the faulty capacitor.
D)
Defective selector switch
S1.
Repair
or
replace
the switch.
7\
Speaker
works normally but
headphones
do not work.
A)
Headphone plug does not
mate
with jack.
Replace
the
plug.
B)
Defective
resistor R651a,
b.
Replace
the
resistor.
8)
All the
inputs work normally except
AUX
input.
A)
Poor
contact in AUX input
jack.
Repair
or
replace
the jack.
B)
Poor contact in selector switch
S1
9)
PHONO
input not
operative.
A)
Poor
contact in
PHONO
input jack.
Repair
or
replace
the jack.
B)
Faulty selector switch
S1.
Repair
or
replace
the switch.
10)
TAPE OUT not operative.
A)
Defective
contact
in
TAPE OUT jack.
Repair
or
replace
the jack.
1
1
)
FM does not operate.
A)
Defective
diode D833.
Replace
the diode.
Transistor
TR831 damaged (open).
Replace
the transistor.
Defective
resistor
R831.
Replace
the
resistor.
Short-circuit
in
Tuner B+ circuit.
Repair the short.
Poor
contact in selector switch
S1.
Repair
or
replace
the switch.
Resistor R301 defective.
Replace
the
resistor.
Capacitor C301 defective.
Replace
the capacitor.
Defective lC
1C201
,lC2O2,lC203 or
1C301.
Replace
the defective
lC.
Defective IFT T201.
Replace
the lFT.
B)
C)
D)
E)
F)
G)
H)
t)
15