Sharp VC-M23SM Servicehandbuch Seite 22

a PB CHROMA envelope (TPSO1)
na f°
CH-1 |_CH-2
Head switching pulse (TP 302)
Figure 4-34, |
7. Adjustment of A/C head height and azimuth
a) Connect,an oscilloscope to the audio output terminal.
b) Using 'the alignment tape with linear audio pre-recorded
signal of 1 KHz, adjustthe screws ® and © to maximize the
audio output, and adjust the screw A to eliminate wrinkles
from the tape at the retain guide flange. (Refer to P21-6-f.)
Repeatedly adjust the screws @, © and ©@ in this se-
quence until the audio output becomes the maximum. 1. (1 to
3 times as ordinary)
c) Using the alignment tape which records a linear audio
signal of 6 kHz, finally adjust the screw © until the audio
output becomes the maximum.
When the a is above the helical lead.
8. Adjustiént of tape drive train'and X-Position
bee the alighment tape VROGPRSV:): -
a) Connect the oscilloscope to the test: Escints cr ee for PB
envelope output: Set the synchronism of the osaillosvape
to EXT.
- The PB signalis ta:be triggered:by the head switching ae
(TP302).
-b). Play. back the tape drive train alignment.tape.
c} Push the (+) or (-) button to change the envelope waveform
from MAX to MIN, and MIN to MAX.
Adjust the guide roller's height on the. supply and take-up
sides With an adjusting screw driver;to obtain an envelope
- wavetorm that is as flatas possible: © vie
d) lf the tape is above or below 'the: helical lead; the PB
waveform will take the shape shown in Figure.4-35.
' 8) Adjustfor maximum. flatness of the. oe as the:stép 6,
',@) in page 21. '3
'f) Push. the (4) ior (+) Packing! bition to check that a flat
' . response is obtained on the envelope waveform.
pe ae a e "
_ When the eee, is below the helical lead.
Supply side guide roller
rotated in clockwise
direction {lowers guide
roller) to flatten
envelope.
Take-up side guide roller
rotated in clockwise
direction (lowers guide
roller) to flatten
envelope.
Figure 4-35.
22
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-rolleris,then:: .
rotated in the clockwise. hey
direction to flatten the
envelope.
Take-up side guide roller
rotated in counterclock-
wise direction (raises
guide roller} to make the
" Ftape float'above the
helical lead: The take-up
side guide roller is then
rotated in.the clockwise
direction to flatten the
envelope.