Sharp MD-C2 Service Manual page 24

MD-C2
Lead-in switch position measurement mode
Insert High reflection test disk (TGYS1)
Note: Adjust the lead-in switch position to FF85 to FFDF.
1. Loosen the screw (A) x 2 pcs. which fix the mechanism switch
PWB.
2. Retighten the screw, pressing the mechanism switch PWB in
the arrow direction, and then measure the lead-in switch
position again.
After position adjustment fix with the two screws (A). (See Fig. 24-1.)
Note: After tightening the two screws on the PWB apply Screw Lock.
Forced rotation of loading motor
When STOP or EJECT appears in the display and the MD RELEASE
key is pressed, it allows the loading motor to be forced to run (loading
and unloading operations).
Forced movement into the loading mechanism throttle
positions
When STOP or EJECT appears in the display and the CD1 PLAY -
CD3 PLAY keys are pressed, the MD throttle mechanism can move
to positions 1 - 3.
Adjustment of magnetic head mounting position
When the magnetic head and optical pickup have been replaced, be
sure to adjust the mounting position.
For easier adjustment of mounting position move the optical pickup
to the center position, and then adjust the position.
1. Set the adjusting transparent disc 3.
2. Lower the magnetic head up-shift arm with your finger, and raise
the magnetic head.
3. Viewing the set from above, make an adjustment so that the
magnetic head aligns with the optical pickup objective lens.
4. Make sure that there is a clearance as shown in Figure 24-2 and
the magnetic head moves up and down smoothly.
Mechanism Adjustment
1. Optical pickup grating inspecting method
43 Pin of IC1101
GND (TP1131)
100K
26 Pin of IC1101
EOUT (TP1133)
470p
470p
25 Pin of IC1101
100K
FOUT (TP1132)
Figure 24-3 Optical Pickup Grating Deviation
Measuring Method
After the automatic adjustment has been performed in the AUTO
mode (test mode) using the low reflection test disk MMD212 (TEAC)
("COMPLETE" will have been displayed), adjust the Lissajous
waveform (x-y) using EOUT and FOUT.
1. Slightly loosen the 3 screws of spindle motor, and make an
adjustment, observing the Lissajous's waveform.
2. After the adjustments are complete, tighten the screws in numerical
order: 1 , 2 and then 3 .
Connection of extension cable
MD MAIN PWB
EXTENTION CABLE
QCNWK0122AFZZ
Figure 24-5
a
OSILLOSCOPE
GND CH1 CH2
b
X Y
LISSAJOUS'S WAVEFORM
Less than a:b = 4:1
MD CHANGER UNIT
MD CHANGER
SWITCH PWB
Loosen the two screws(A)
Optical Head
Objective lens
Circumferential direction
Spindle Motor
Adjusting hole
2
DISPLAY PWB
EXTENTION CABLE
QCNWK0123AFZZ
– 24 –
Lead in Switch
MD Mechanism Switch PWB
Figure 24-1
Radial direction
Push
Optical Head
Figure 24-2
2
3
1
3
Spindle Motor
Adjusting
hole
1
Figure 24-4
MAIN PWB
Figure 24-6