Sharp vc-ga56z Service Manual page 22

VC-GA56Z
VC-GH96Z
3 Next, Press the tracking button (+), (–) and change
the envelope waveform from max to min and from
min to max. At this time adjust the height of supply
and take-up side guide roller with the adjustment
driver (JiGDRiVERH-4) so that the envelope wave-
form changes nearly parallel.
4 If the tape is lifted or sunk from the helical lead
surface, the PB CHROMA envelope waveform ap-
pears as shown in Figure 4-35.
5 Press the tracking button (+), (–) and make sure
that the envelope waveform changes nearly paral-
lel.
6 Finally check tape crease near the reverse guide. If
tape crease is found, remove it as stated in 4-17
"HEIGHT ADJUSTMENT OF REVERSE GUIDE"
item 3.
Adjustment
3 Move the A/C head with the X value adjustment
gear driver by the method shown in Figure 4-33,
and adjust the A/C head so as to get the maximum
envelope waveform. (Note: At this time adjust so as
to get the maximum envelope waveform nearest
the A/C head position which has been set in case of
X value rough adjustment as stated in 4-18, 3- 2.)
4 Tighten finally the screws 1 and 2. Be sure to
tighten at first the screw 1 and then the screw 2.
Final tightening torque is 0.6N·m (If the screw 2 is
tightened first, the X value may deviate.)
5 Adjust the playback switching point (Refer to the
electric adjustment method.)
6 Playback the self-picture-recorded tape, and check
the flatness of envelope waveform and sound.
When the tape is above the helical lead.
Supply side
Supply side guide roller Take-up side guide roller
rotated in clockwise rotated in clockwise
direction (lowers guide direction (lowers guide
roller) to flatten roller) to flatten
envelope. envelope.
Figure 4-35.
PB CHROMA
Envelope
4. A/C head X value adjustment
1 Tentatively fix A/C head arm screws 1 and 2 by the
method described in 4-15 "Replacement 3".
2 Playback the alignment tape (VROATSV), and
shortcircuit TP801 and TP802. As a result the auto-
tracking is automatically cancelled, so that the X
value adjustment mode is set.
When the tape is below the helical lead.
Take-up side Supply side
Supply side guide roller
rotated in counterclock-
wise direction (raises
guide roller) to make the
tape float above the helical
lead. The supply
side guide roller is then
rotated in the clockwise
direction to flatten the
envelope.
Notes:
When the A/C head X value adjustment is performed, be
sure to perform at first X value rough adjustment (refer to
4-18, 3-2).
2
22
CH-1 CH-2
Head switching pulse
Figure 4-34.
Take-up side
Take-up side guide roller
rotated in counterclock-
wise direction (raises
guide roller) to make the
tape float above the
helical lead. The take-up
side guide roller is then
rotated in the clockwise
direction to flatten the
envelope.
1
Figure 4-36.