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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 kHz 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 kHz signal (colour 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 glyptal to the
screws and nuts to fix them.
When the tape is above the helical lead.
Supply stde guide
roller rotated in
(lowers gurde roller) to
Adjustment
flatten envelope
Supply side
Take-up side
roller rotated in
clockwise dIrectron
(lowers guide roller) to
flatten envelope.
Azimuth adjusting
screw
Figure l-59.
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 (TP502).
b) Play back the tape drive train alignment tape.
envelope waveform from MAX to MIN, and
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 1-61.
e) Adjust for maximum flatness of the envelope
as the step 5, e) in page 26.
When the tape is below the helical lead.
Supply side
Supply side guide
roller rotated in
direction (rarses gurde
roller) to make the
tape float above the
helical lead. The
then rotated in the
flatten the envelope.
Figure i-61.
27
Box driver
Figure l-60.
Take-up side
Take-up side gurde
roller rotated In
direction (raises
roller) to make t If e
tape float above the
helical lead.
supply
The take-up srde gurde
roller is then rotated rn
the clockwise directton
to flatten the
envelope.
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