Sharp 14VT10X1, Service Manual

Page: 25 / 138

Figure l-58.
6. Adjustment of A/C head height and azimuth
a) Connect an oscilloscope to the audio output
terminal.
b) Use the alignment tape and play back its
audio 6 signal (monoscope pattern for
video signal). Adjust the azimuth adjusting
screw to obtain the maximum audio output
on an oscilloscope. (See Figure l-59.)
c) Use the alignment tape and play back its
audio 1 signal bar for video signal)
a n d s l o w l y r o t a t e t h e A / C h e a d h e i g h t
adjusting nut with the special box driver to
obtain the maximum audio output.
d) Perform the adjustment in b) again.
e) After this adjustment, apply to the
screws and nuts to fix them.
Azimuth adjusting
screw
Box driver
Figure l-59.
Figure
7. Adjustment of tape drive train and X-Position.
a) Connect the oscilloscope to the test points
(TP501) for PB CHROMA envelope output. Set
the synchronism of the oscilloscope to EXT.
The PB CHROMA signal is to be triggered by
the head switching pulse
b) Play back the tape drive train alignment tape.
Push the or button to change the
envelope waveform from MAX to and
to MAX. Adjust the guide roller’s height
on the supply and take-up sides with an
adjusting screw driver, to obtain an envelop
waveform that is as flat as possible.
d) If the tape is above or below the helical lead,
the PB CHROMA waveform will take the shape
shown in Figure
e) Adjust for maximum flatness of the envelope
as the step 5, in page 26.
When the tape is above the helical lead. When the tape is below the helical lead.
Supply side Take-up side
Supply side Take-up side
Supply guide
Supply
Take-up side
roller rotated in roller rotated in
roller rotated in
roller rotated
direction clockwise
Adjustment
(lowers roller) to
(lowers guide roller) to
direction
direction (raises
roller) to make
flatten envelope
flatten envelope.
roller) to make the
tape float above the
tape float above the
helical lead.
helical lead. The
supply
guide roller
The take-up
roller is then rotated
then rotated in the
the clockwise
to
to flatten the
flatten the envelope.
envelope.
Figure
27