Sharp MD-MX30 Service Manual page 27

Lead-in switch position measurement mode
Insert the high reflection test disk TGYS1.
Note: Adjust the lead-in switch position within the range of FF85 -
FFD2.
1. Measure the lead-in switch position. Loosen the screw (A1) x 1 pc.
which fixes the mechanism switch PWB.
2. When the lead-in switch is located FF85 or less, tighten the screw
while pressing the PWB in the direction of the arrow A. When FFD2
or more, to direction B. Measure the lead-in switch position again.
After position adjustment is completed, fix the PWB with the screw
(A1) x 1 pc.(shown in Figure 27-1)
Magnetic head mounting position check
•
Check the mounting position whenever the magnetic head and the
optical pickup are replaced.
•
Move the optical pickup to the center to adjust the position easily.
1. Set the adjusting transparent disc 3.
2. Press down the magnetic head up shift arm by hand to raise the
magnetic head.
3. View the set from above to check whether the magnetic head aligns
with the optical pickup objective lens.
4. Check that the magnetic head moves up and down smoothly.
(shown in Figure 27-2)
Rotating the loading motor forcibly
The loading motor can be rotated forcibly by rotating the VOLUME
UP/DOWN knob while STOP or EJECT in the test mode appears on
the display.
Mechanism Adjustment
1. Optical pickup grating inspecting method
4Pin of IC1201
GND (TP1202)
6Pin of IC1201
EOUT (TP1129)
9Pin of IC1201
FOUT (TP1130)
Figure 27-3 Optical Pickup Grating Deviation
Measuring Method
After auto adjustment (COMPLETE appears) in the test mode (auto)
using the high reflection MD disc TGYS1, adjust the Lissajous
waveform (x-y) of EOUT to FOUT.
1. Slightly loosen the 3 screws of the spindle motor, adjust while
observing the Lissajous waveform.
2. After adjustment, tighten screws 1, 2, and 3 in numerical order.
(See Fig. 27-4.)
OSILLOSCOPE
100K
470p
GND CH1 CH2
470p b
X Y
100K
LISSAJOUS WAVEFORM
Less than a:b = 4:1
– 27 –
Figure 27-1
Magnetic head
Tangential direction
Objective lens
Radiai
Head up- shift arm
Figure 27-2
a
2
1
Check the Lissajous waveform,
3
shifting the mounting position with
a screwdriver (to be fitted into the
disc motor adjusting hole).
adjusting
hole
Figure 27-4
MD-MX30/MX30W
A
B
(A1) X1
2
3
1