Technics SL-220

@ CHECK POINTS
(A) Switching on does not cause turntable to rotate
1) Check the line power circuit
2) Check for 12V DC between @ - ©
a) Replace speed selector switch
b) Solder securely
3) Check speed selector switch
a) Faulty contact b)Soldered improperly|
4) Check VR1, VR2, VR3 or VR4 a) Replace VR1, VR2, VR3 or VR4
a) Faulty b) Soldered improperly b) Solder securely
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5) Separate motor and the F.G. SERVO P.C.B
6) Confirm that motor rotates with 5V DC applied between the red lead |BAD
(Positive) and the blue lead (Negative) separate source and see that the Replace’motor
noload is about 20mA
Replace F.G. SERVO P.C.B.
Turntable rotates abnormally
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1) Adjust VAI, VR2, VRS or VR4 When the strobe dots appear to be stationary, the speed
STILL ABNORMAL
a) Replace VR1, VR2, VR3 & VR4 or speed selector switch
b) Solder securely
(B)
3) Check VR1,VR2, VR3 & VR4 or speed selector switch |BAD)
a) Faulty contact —b) Soldered improperly
OK
4) Check for 12V DC and a ripple voltage of [BAD] Check ripple filter and diodes
about 0.5Vp-p between @- © If faulty, replace
[B)Separate motor and the F.G. SERVO P.C.B]
6) Connect a separate 5V DC power supply between the red lead (positive) BAD
and the blue lead (negative) of the motor.
Motor should rotate. Connect oscilloscope between the white lead
(positive) and the red lead (negative) of the motor.
Confirm that thare is about 120mVp-p.
Replace motor
7) Replace F.G. SERVO P.C.B.