Panasonic Omnivision PV-M1378W, Руководство по обслуживанию

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2-22
TAPE INTERCHANGEABILITY
ADJUSTMENT (FINAL ADJUSTMENT)
Note:
To perform these adjustment/confirmation procedures, set
the tracking to the neutral position.
Equipment Required:
Dual Trace Oscilloscope
VHS Alignment Tape ............................... (VFMS0003H6)
Post Adjustment Driver .................................... (VFK0329)
H-Position Adjustment Driver ........................ (VFK0330)
1. ENVELOPE OUTPUT ADJUSTMENT
Purpose:
To achieve a satisfactory picture and secure precise
tracking.
Symptom of Misadjustment:
If the envelope is output poorly, much noise will appear in
the picture. Then the tracking will lose precision and the
playback picture will be distorted by any slight variation of
the tracking control circuit.
Equipment Required:
Post Adjustment Driver .................................... (VFK0329)
1. Connect the oscilloscope to TP3002 on the Main C.B.A.
Use TP6205 as a trigger.
2. Place a jumper between TP6003 and +5V(TP6009) on the
Main C.B.A. to defeat Auto Tracking.
3. Eject the tape and insert it again to access the Neutral
Tracking position.
4. Play back the alignment tape and confirm that the RF
envelope appears.
5. With Post Adjust Driver, adjust P2 and P3 post height so
that the envelope waveform (V
1
/V-
max.
is 0.7 or more.)
becomes as flat as possible (No envelope drop). If the
envelope drop appears on the left-half of the waveform,
adjust P2 post height. If the envelope drop appears on the
right-half of the waveform, adjust P3 post height.
Fig. M6-1
Fig. M6-2
Note:
To confirm adjustment, press the Tracking Control Up or
Down button on remote control. Make sure that the envelope
waveform remains flat. If not, readjust P2 and/or P3 post
heights.
6. After adjustment, confirm that the tape travels without
curling at P2 and P3 posts.
7. Remove the jumper after completing the adjustment
procedure.
Fig. M6-3
Note:
Overtightening P2 and P3 posts may cause the threads to
strip.
V1 V1
V
Envelope Waveform
V1/V-max. 0.7
Left half
Adjust P2 post Right half
Adjust P3 post
Cylinder
P2 Post
P3 Post
Tape
Audio
Control
Head
Full Erase
Head
No Good
Good
No Good