Trouble Shooting (Power Supply Section) - Sharp MD-M3 Service Manual

• Disc motor fails to run
Does waveform appear on the pins 24 and 25 of IC1201 in the
TEST mode focus gain coarse adjustment step?
Does waveform appear on the pins 34 and 35 of IC1601, pins
1 and 2 of CN1603?
Replace the completed disc motor.
• Tracking servo failure
Does waveform appear on the pins 8 and 9 of IC1601, and pins
1 and 3 of CN1101 in the TEST mode focus gain adjustment
step?
Replace the optical pickup.
• Slide servo failure
Does the pickup move to external and internal periphery when
the or button is pressed in the TEST mode?
Is there any change on the pins 22 and 23 of IC1201 when the
or button is pressed?
Is there any change on the pins 28 and 29 of IC1601, and the
pins 1 and 2 of CNP1602 when the
pressed?
Does voltage on the positive and negative terminals of slide
motor change when the or
Replace the sled motor.
POWER SUPPLY SECTION
• Although the power is turned on, the device does
not turn on.
Pin 76 on ICD01 changes from L to H.
Yes
Power relay RL990 turns on.
Yes
The 5V MDVDD line is powered up. (ZD806
cathode)
Yes
Yes
Yes
No
Yes
or button is
Yes
button is pressed?
Yes
No
When the POWER button is pressed,
pin 22 of ICD01 will change from 5V to
0V.
Check between pin 76 on ICD01 and
No
Q911.
Check the power circuit (F999, Q811,
No
Q812,ZD806 etc)
Check soldering joint and parts of pins 24 and 25 of IC1201, and
No
peripheral circuit.
Check soldering joint of PWB of completed IC1601 and CN1601 disc
No
motor.
Check the soldering joint of pins 20 and 21 of IC1201, IC1601,
No
CN1101.
Check the waveform on the pins 22 and 23 of IC1201, check the
Yes
peripheral parts and soldering joint.
Check the waveform on the pins 22 and 23 of IC1201, check the
No
peripheral parts and soldering joint.
Check the soldering joint of IC1601 and CN1602.
No
Check the soldering joint connected to the sled motor to see whether
No
there is wire breakage.
No
– 65 –
MD-M3/M1
Check between POWER button and pin
22 on ICD01.