Sharp VC-MH80 Service Manual page 25

that a flat response is obtained on the enve-
guide roller setscrew in the unloading mode.
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
low side envelope.
c) Adjust the playback switching point.
and sound by playing back a recorded tape.
X-position adjusting
REPLACEMENT OF THE CAPSTAN D.D.
(DIRECT DRIVE) MOTOR
Remove the cassette
Removal (Follow the order of indicated
bers.)
1. Disconnect from the board-to-board connector
on the main PWB.
2.
Remove the Gel belt 0.
3.
Remove the screws 8.
nut
Main chassis
control assembly.
housing
num-
Capstan D.D. motor
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
Put the unit in the cassette eject position.
1.
2.
Unplug the power cord.
Removal (Reverse the order in reassembly.)
1.
Disconnect the FFC cable 0.
2.
Unscrew the stator assembly fixing screws @.
3.
Take out the stator assembly 0.
4.
Unscrew the rotor assembly fixing screws @I.
5.
Take out the rotor assembly @.
Notes:
1. In removing the stator assembly, part of the In 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.
2.
Secure the rotor assembly so that the installation Secure 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.)
3.
Be careful not to damage the upper drum or the Be careful not to damage the upper drum or the
video head. video head.
4.
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 or bly are not damaged by the rotor assembly or
other parts. other parts.
5.
After installation, adjust the playback switching After installation, adjust the playback switching
point. point.
25
VC-MH80