Sharp 37VT-26H Service Manual page 34

37VT-26H(GY)
4 If the tape is lifted or sunk from the helical lead
surface, the PB CHROMA envelope waveform
appears as shown in Figure 1-35.
5 Press the tracking button (+), (–) and make sure
that the envelope waveform changes nearly par-
allel.
6 Finally check tape crease near the reverse guide.
If tape crease is found, remove it as stated in 17.
"HEIGHT ADJUSTMENT OF REVERSE GUIDE"
item 3.
Adjustment
4. A/C head X value adjustment
1 Tentatively fix A/C head arm screws 1 and 2 by
the method described in 15. "Replacement -3.".
2 After shortcircuiting TP7701 (J930) and TP7702
(J359), plug in the power cord, turn off the power,
set the alignment tape (VROCPSV), turn on the
power and then playback the tape. As a result the
auto-tracking is automatically cancelled, so that
the X value adjustment mode is set.
3 Move the A/C head with the X value adjustment
gear driver by the method shown in Figure 1-33,
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 near-
est the A/C head position which has been set in
case of X value rough adjustment as stated in 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.)
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 1-35.
PB CHROMA
Envelope
Head switching pulse
When the tape is below the helicallead.
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.
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.
Note:
When the A/C head X value adjustment is performed, be
sure to perform at first X value rough adjustment (refer
to 18., 3-2).
2
34
CH-1 CH-2
Figure 1-34.
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 1-36.