Sharp 14VT10X1, Service Manual

Page: 24 / 138

ADJUSTMENT OF TAPE DRIVE TRAIN
1. Remove the cassette housing control assembly.
2. Check and adjust the position of the tension
pole. (See page 2 1.)
3. Check and adjust the video search rewind back
tension. (See page 20.)
4. Set the tilt angle of the A/C head. (See page 24.)
5. Rough adjustment of tape drive train.
a) Connect the oscilloscope to the test point for
PB CHROMA envelope output (TP501). Set the
synchronism of the oscilloscope to EXT. The
PB CHROMA signal is to be triggered by the
head switching pulse
b) Loosen the setscrew at the lower part of the
guide roller, and adjust it with an adjusting
screw driver (JIGDRIVERH-4) so that the guide
roller turns smoothly. (Do not the
setscrew, which causes insecurity of the guide
roller.) (See Figure l-53.)
the alignment tape (See the Notes below)
on the reel disk, and place the unit in the
playback mode.
(Place a 500 g. weight on the cassette tape to
prevent floating of the cassette tape.)
Notes
1 Alignment tape.
2 Head VROCPSV (PAL)
VROATSV (NTSC)
Hexagon
Figure l-53. Figure l-54.
d) the envelope waveform from MAX to
MIN, and to MAX by pushing the or
tracking button, and check a flat response
is obtained on the waveform.
e) If a flat response cannot be obtained, roughly
adjust the guide rollers on the supply side and
take-up side using an adjusting screw driver
until a flat response can be obtained.
Turn the A head tilt adjusting screw with a
s c r e w d r i v e r t o p r e v e n t t h e t a p e f r o m
wrinkling at the upper and lower flanges of
the fixed guide.
1) Wrinkles at the upper flange Turn the
above adjusting screw clockwise, as shown
in Fig. 1 55 (a)
2) Wrinkles at the lower flange Turn the
above adjusting screw counterclockwise, as
shown in Fig. 1 55 (b)
Wrinkles at upper flange
Clockwise
lower flange
Counterclockwise
Figure l-55.
Notes:
1. Place the tracking control in the center
p o s i t i o n , a n d a d j u s t t h e X - p o s i t i o n
adjusting nut so that the PB CHROMA
envelop becomes maximum for easier
rough adjustment of the tape drive train.
2. In the rough adjustment, pay particular
attention to the outlet side.
Loosen the setscrew
Figure l-56.
Figure
26