JVC L-A31

10. Trouble Shooting
10-(1) When turntable operation is abnormal
The turntable does not rotate.
OC 18.6 V ap-
pear between the posi-
tive and negative ter-
Yes
The connection cord is
in contact with the
power supply board,
Does any
voltage appear at the
emitter of ,
X801?
Yes
the soldered joint is not
perfect, or some other
cause.
No
X802 is open or short-
circuited, 0802 is short-
Does
any voltage | circuited, R801 or
appear at the col- ; R802 is disconnected,
lector of or some other cause.
X801? Replace the defective
element.
0801 is open, its as-
sociated pattern is dis-
connected, or some
other cause. Replace
the defective element.
Does an
AC voltage appear
between pins (1)
and (2)?
Note:
Pins (1) and (2) are
located on circuit
board TPS-300. °
Check the connection
of the transformer, the
soldered joint of the
AC cord, or the like. If
anything is defective,
replace it.
Does the
turntable rotate Yo. Check whether or not R18 is
when a short-circuiting is disconnected, or whether or
‘made between TP-2 not IC1 is defective. ifnot,...
and TP.3?
No
Does the
turntable rotate
when a short-circuiting is
made between the collector
and emitter of
X12?
X12 is open, its associated
Pattern is disconnected, or
some other cause.
Yes
No
Does the
turntable rotate
when a short-circuiting is
made between the collector
and emitter of
: X11?
X11 is open, the pattern be-
tween the collector of X12: -
and the base of X11 is discon-
nected, or some other cause.
Ye
No
Does
an output
the turntable is
rotating?
Yes
Does an
Output appear
between the bases of X5 and
Any of X1 — X8 is defec-
tive, the drive coil is dis-
X7 or between the bases connected, or some other
of
X6
and
©
cause.
X8?
No
Any one of R2 — R& is discon-
nected, or Ome Other cause.
-12-
Does the appear between the
turntable rotate by base of X5 and X7 or between the
hand? bases of X6 and X8 when
-4
connectic~ wire
of the spete select
circuit dscon-
nection wre.
Yes Replace the con-
nection wire.
Replace the speed
select switch. ©
Does certact
failure occ.r in the
speec mect
sans?
¥ No
R25 or R31 is
Gefective, or the
connection cord is
disconnected, or
some other cause.
Doe: -ne
turntabe “orate
at eithe” >:-1/3 or
45 F=NN7
Anelement ezund!C1, | . : :
such as C4. =24 etc., is a
defective, o° x:me
other cause
Check whe=er or not
the Hall ele~ert associ-
ated with te sar of
bases betwee- which no
Output appeirs is defec-
tive.
, L-A31
No. 2555