JVC GR-SXM195AS Service Manual page 32

Compact vhs camcorder
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NOTE:
To prevent the tape from damage, turn the guide rollers
slowly.
(7) By operating the tracking button (both in + and - directions)
in the manual tracking mode, vary the output level of the
FM waveform from maximum to minimum and vice versa to
confirm that the waveform varies nearly in a flat shape.
(8) When the FM waveform breaks in the level varying process,
subtly adjust the height of guide rollers at every breaking
point so that the waveform varies as flat as possible.
Repeat the above steps 6. and 7. several times to confirm
that the waveform is flat as a whole.
(9) Playback the SP stairstep signal of alighment tape and ad-
just the tracking control to maximize the FM waveform,
confirm that FM waveform variation is always flat.
(10) Record the signal and play it back in both of the SP and LP
modes, and confirm that the FM waveform is flat in both
modes.
NOTE:
Among the above-mentioned adjustment steps, the
items of No.9 and No.10 are needed for the LP model
only.
CH-2
CAUSER BY WRONG HEIGHT
CAUSED BY WRONG HEIGHT
OF SUPPLY GUIDE ROLLER
OF TAKE-UP GUIDE ROLLER
Fig.3-3-5
CORRECT VARIATION OF WAVEFORM
BAD VARIATION OF WAVEFORM
Fig.3-3-6
(11) Through the above steps, confirm that there occur no wrin-
kling and damage in the tape around the PINCH ROLLER
and TU GUIDE POLE whenever the deck is in operation of
Loading/Unloading, Search Rewind and at mode change
from Search Rewind to play mode. If wrinkling or damage
in the tape occurs around the TU GUIDE POLE, adjust the
angle (slant) of the A/C HEAD to the tape. So that the tape
normally runs along the lower flange of the GUIDE POLE.
1 field
FLATTEN WAVEFORM.
3.3.4 A/C head height & azimuth
Remove the exterior parts attached to the UPPER CASE
ASSEMBLY so that the screws around the A/C HEAD
ASSEMBLY can be tighten or loosen.
• LOWER CASE ASSEMBLY
• TOP OPE UNIT
• CASE COVER(S),(M) ASSEMBLY
• UPPER CASE (S),(M) ASSEMBLY
• FRONT FRAME ASSEMBLY
NOTE:
In performing adjustment, it is recommended that LOWER
CASE ASSEMBLY and TOP OPE UNIT are attached to the
main body for better operation and safety.
(1) Remove the Cover (JIG) shown on Fig.3-4-1.
(2) Connect the JIG CONNECTOR CABLE to CN25 on the
MAIN BOARD ASSEMBLY.
(3) Connect the channel-1 scope probe to the audio output
(AO_SIG_J) and connect the channel-2 scope probe to PB
CTL.
(4) Playback the alignment tape.
(5) Set the tracking to its center range by pressing the (+) and
(-) tracking controls simultaneously.
(6) Adjust screws A , B and C approximately 45 degrees in the
same direction to obtain maximum audio output and CTL
signal levels.
(7) As a final fine adjustment, adjust screw B for minimum sig-
nal level fluctuation and screw C for maximum output sig-
nal level.
A/C HEAD
SCREW A
SCREW C
SCREW B
Fig.3-3-7
Audio
signal
Control
pulse
signal
Fig.3-3-8
(No.86712)1-21

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