Sony WM-10 - No Speed Acceleration; Servo Board (A);(B) Simple Check Method

WM-10 WM-20
CONTROL CIRCUIT STARTING CIRCUIT
• No Speed Acceleration
* Acceleration Circuil Operation
Leaf switch S303-2(FF/REW SW) on turns on 0607,
lowering reference voltage which controls servo voltage
(normally 0,8V - 0,6V), and accelerates to about
1.2 times normal speed,
* Servo Board (A) (B} Simple Check Method
Check servo hoard (A) motor side pins (8), A I
waveforms and the voltages of each of the 8 fie
board pins,
The voltages and waveforms should be as shown ii
figure.
* FF/REW Mode
Symptoms Defective Parts
No speed acceleration
R616, R617 \
Q607 ) 0p€n
Q607 short between E-fl
S303-2