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LAs
SL-Q303
m TROUBLE SHOOTING GUIDE
1. No rotation
|
Check point
Checking method
Possible defects
Power supply circuit
Q3 emitter voltage —»14.3V
Q1~3
D1,2
Constant voltage
Q201 emitter voltage —»-9.4V
Q201
circuit
Control circuit
With arm switch (S1) turned on/off, the voltage
S1
(S/S circuit)
changes of IC201 terminal (9) are as follows:
1€201
$1
"on"
—*7.0V
"off" —~
0V
Drive circuit
Voltage at each terminal of 1C101 (in start mode)
(ST... "on'')
Terminal | @
@1®
@|9|©
olel@
@® | @
Voltage
|13.7| 9.4/13.6| 3.3 | 3.3 | 3.3 | 3.3
42/64/51
Terminal] @ | @ | ® | @ | @
a
D2
®@
Voltage hashisoiie shoe 06/06]
0
[06/06]
0 | 80
Slol®
~ a
Note:
Besides the above-mentioned defects, burnt-out drive coil is also possible.
But if it ison
one phase, the motor
rotates although the driving torque is halved.
Also, it is possible that both Hall elements are defective.
2. Abnormal rotation
|
Check point
Checking method
Possible defects
FG amplifier circuit
Solder lead wire to terminal @3 of 1C201; remove
Q203
it from the bottom plate and measure the waveform
1C201
in the state of rotation. (See Fig. 17)
FG coil pattern
breakage
20ms.
2.8V
a
eT,
A Vv
Voltage of 1C201 terminal (7) 5.1V
2
Control circuit
(Reference voltage circuit)
Lead wire
TS
Fig. 17
~~) Mie
kc} 0 Fc |
3. Unstable rotation
(Uneven rotation, repeat of normal and reverse rotations)
Control circuit
Measure the waves at 1C201 terminals @) and @).
(Crystal oscillator)
2us.
Possible defects
2.6V
O6V 4 oy
Control circuit
(Brake, timer circuit)
(Stn 28 "on"')
@) ——>5.9V
@) —4.2V
Control circuit
(Control output
circuit)
Instead of FG signal, apply FG signal by CR
oscillator,
(Refer to "How to check the control
circuit.)
Measure the waves at 1C201 terminals @, @, ®.
4. Others
Strobe LED does not
Q202 collector output waveform.
light up.
10ms.
13V
®How to check the control circuit
Instruments used
Setting
1. CR oscillator
1. Remove the turntable and panel cover.
2. Oscilloscope (Two channel type)
(Refer to "Disassembly instructions")
3. 50V 1uF electrolytic condenser
2. Remove the connector (CN2) from the arm switch.
3. Unsolder the positive @ side of C203.
[22]
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