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7. Troubleshooting
7-(1) Platter does not rotate
Platter does not rotate.
ts22;05V
available at TP-5 when the
Power switch is
turned on?
Yes
No
Is a voltage
present at the
collector of transistor
X815?
Yes
No
Is an AC voltage present
,
Yes
between lapping tabs 7 — 8.
No
Fuse
or
transformer
dis-
connected. AC cord solder-
ing defective.
Transistor
X815
—
X817
or diode D809 defective.
Diode D810
— D813 open
or incorrectly soldered.
Hall
elements
open.
Motor
disconnected
inside,
dis-
connected resistors.
Does the platter
rotate when R822 is
short-circuited?
Yes
No
Does the platter rotate
when pins 1 and 8 of IC 803
are short-circuited?
Yes
No
Does platter rotate
when emitter and collector of
transistor X803 are
short-circuited?
Does platter rotate by hand?
fs output available
at voltage terminals of Hall
elements HG-1 and HG-2?
Does platter rotate
when pins 6 and 1 of IC802
are short-circuited?
IC802 defective.
1C803 defective.
Transistor
X803
is open be-
tween emitter and collector.
Transistors
X805
—
X812
defective.
Lead
from
circuit
board
to
motor
discon-
nected.
Check
for
loose
socket,
floating
pattern
and
defective soldering.
.
Check
for
incorrect
ca-
is the oscillation waveform
pacitance or defective solder-
available at TP-3?
ing of IC801.
1s diode D801 or
capacitor C808
not defective?
Yes
Replace defective part.
Notes for replacement of transistors X809 — X812
There are 4 ranks K1, K2, L1 and L2 for 2SD571 transistor
hfe. Be sure to use those transistors of the same ranking
when replacing.
Warning !
1. Be careful not to allow metallic dust, etc. to enter
inside the unit, be cause its motor is comprised of
magnetic elements.
2. After
replacement
of the X813
transistor, apply
KE45RTV
(silicone
adhesive)
or an
equivalent
material
around
the transistor
for thermal
con-
duction.
QL-A2
No. 2444
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