Sharp VC-MH80

VC-MH80
VC-MH90
f) Push the (+) or (-) tracking button to check
that a flat response is obtained on the enve-
-~~~~~~~~~ lope ww&m~---- .-.~_-~--~.
g)Secure the guide roller by tightening the
guide roller setscrew in the unloading mode.
h) Play back the tape drive train alignment tape
to check that the envelope waveform does
not change.
9. Adjustment of A/C head X-position.
a) In the X value adjustment mode (see the Elec-
trical Adjustment), make a short-circuit be-
tween the test jumpers 3 and 4 on the timer
PWB in order to center the tracking.
b) Rotate the X-position adjusting nut with an
adjusting box driver, and adjust the A/C head
.position for maximum -head-switching pulse
low side envelope.
c) Adjust the playback switching point.
d) Check the flatness of the envelope waveform
and sound by playing back a recorded tape.
X-position adjusting nut
l-2mm L
&
II
Main chassis
Figure 4-42.
REPLACEMENT OF THE CAPSTAN D.D.
(DIRECT DRIVE) MOTOR
0
0
1.
2.
3.
Remove the cassette housing control assembly.
Removal (Follow the order of indicated num-
bers.)
Disconnect from the board-to-board connector
on the main PWB.
Remove the Gel belt 0.
Remove the screws 8.
Capstan D.D. motor
Figure 4-43.
25
0 Reassembly
1. Mount the capstan motor on the mechanism
chassis making sure not to allow the capstan
shaft to hit the mechanism chassis, and attach it
with the three screws.
2. Attach the reel belt. Reconnect to the board-to
board connector on the main PWB.
Notes :
1. After installing the capstan D.D. motor, be sure
to rotate the capstan D.D. motor and check the
movement.
2. Check the servo circuit.
REPLACEMENT OF DRUM D.D. MOTOR
1.
2.
a
1.
2.
3.
4.
5.
Put the unit in the cassette eject position.
Unplug the power cord.
Removal (Reverse the order in reassembly.)
Disconnect the FFC cable 0.
Unscrew the stator assembly fixing screws @.
Take out the stator assembly 0.
Unscrew the rotor assembly fixing screws @I.
Take out the rotor assembly @.
Notes:
1.
2.
3.
4.
5.
In removing the stator assembly, part of theIn removing the stator assembly, part of the
drum earth spring pops out of the pre-load col-drum earth spring pops out of the pre-load col-
lar.lar.
Be careful not to lose it.Be careful not to lose it.
Secure the rotor assembly so that the installationSecure the rotor assembly so that the installation
positioning holes in the rotor assembly and up-positioning holes in the rotor assembly and up-
per drum assembly match.per drum assembly match.
(Match the upper drum’s notch with the rotor’s(Match the upper drum’s notch with the rotor’s
hole.)hole.)
Be careful not to damage the upper drum or theBe careful not to damage the upper drum or the
video head.video head.
Be sure that the hall device and the stator assem-Be sure that the hall device and the stator assem-
bly are not damaged by the rotor assembly orbly are not damaged by the rotor assembly or
other parts.other parts.
After installation, adjust the playback switchingAfter installation, adjust the playback switching
point.point.
Figure 444.