Sharp VC-G20SM Serviceanleitung Seite 18

VC-G20SM/G200SM
VC-G201SM/G401SM
4-16 A/C HEAD HEIGHT ROUGH ADJUSTMENT
• Setting
Azimuth screw
Weight to prevent
float (500g)
Figure 4-24.
1. Set the cassette tape in the unit.
2. Press the PLAY button to put the unit in the playback
mode.
3. Roughly adjust the height of the A/C head by turning the
height screw until the tape is in the position shown
A/C head
below.
Tape
Figure 4-25.
• Adjustment
Adjust the height screw visually so that the control head is
visible 0.3mm below the bottom of the tape.
TiH screw
Height screw
Cassette tape
500g
Mechanism chassis
0.3mm
4-17 ADJUSTMENT OF TAPE DRIVE TRAIN
1. Tape run rough adjustment
1 Check and adjust the position of the tension pole.
(See 4-12.)
2 Check and adjust the video search rewind back
tension. (See 4-10.)
3 Connect the oscilloscope to the test point for PB ATR
signal output (TP201). Set the synchronism of the
oscilloscope to EXT. The PB ATR signal is to be
triggered by the head switching pulse (TP202).
4 Set the alignment tape (VROUBZFS) to play.
Guide roller
5 Press the tracking button (+), (–) and change the
ATR signal waveform from max to min and from min
to max. At this time make sure that the ATR signal
waveform changes nearly parallel.
6 Unless the ATR signal waveform changes nearly
parallel, adjust the height of supply side and take-up
side guide roller so that the envelope waveform
changes nearly parallel. (For ATR signal adjustment
procedure refer to Figure 4-30.)
7 Turn the tilt screw to remove the tape crease at the
fixing guide flange.
Playback the tape and check for tape crease at the
fixing guide flange.
(1) If there is no tape crease
Turn the tilt screw clockwise so that tape crease
appears once at the flange, and then return the tilt
screw so that the crease disappears.
(2) If there is tape crease
Turn counterclockwise the tilt screw so that the
tape crease disappears.
(Reference) If the tilt screw is turned clockwise
crease appears at the lower flange.
18
Cassette Tape
Figure 4-26.