Panasonic PV-L550 Manual page 67

PV-D300 / VM-D100 / PV-L550 / PV-L600 / PV-L650 / VM-L450
7.2.2.5. A/C HEAD HORIZONTAL
POSITION ADJUSTMENT
Purpose: To adjust the Horizontal Position of the
A/C Head.
Symptom of If the Horizontal Position of the A/C Head
Misadjustment: is not properly adjusted, maximum
envelope can not be obtained at the
Neutral Position of the Tracking Control
Circuit.
1. Put the unit into the service mode "I. Tracking Fix" to defeat
Auto Tracking.
SPECIFICATION" in "SERVICE NOTES."
2. Connect the oscilloscope to Pin 30 (Envelope signal) on the
TP Adjustment P.C.B. Use Pin 33 (Head Switch signal) as
a trigger.
3. Play back the Alignment Tape (VFMS0004H6C).
4. Set the Screwdriver into the Hole (A) as shown.
5. Slowly move the A/C Head Unit to the direction "A" or "B" as
shown so that the envelope is at maximum.
Refer to "SERVICE
Fig. M6-1
Fig. M6-2
6. To find the center of the maximum period of the envelope,
move the A/C Head Unit to confirm the limits on either side
of the maximum period.
Note:
It will be possible to confirm step 6) after performing the
following steps.
a. Exit the "I. Tracking Fix" mode, then skip the "J. PG
Shifter" mode to enter other modes (except these 2). Or,
close the service mode.
b. Press the Tracking Control Up Button on the camcorder
several times (count the number of times pressed) until
the maximum envelope is reduced to 1/2.
MODE
c. Press the Tracking Control Down Button on the
camcorder several times (count the number of times
pressed) until the maximum envelope is reduced to 1/2.
d. If the number of pressing is not the same, readjust
A/C Head horizontal position.
7.2.2.6. CONFIRMATION OF ENVELOPE
OUTPUT
Purpose:
Symptom of
Misadjustment:
1. Connect the oscilloscope to Pin 30 (Envelope signal) on the
TP Adjustment P.C.B. Use Pin 33 (Head Switch signal) as
a trigger.
2. Play back the Alignment Tape (VFMS0004H6C).
3. Confirm that the envelope waveform is as flat as possible
(V1/V(max)> 0.7).
If adjustment is required, adjust S Post and/or T Post with
"—" Screwdriver. Refer to "Envelope Output Adjustment."
66
To achieve a satisfactory picture and
secure precise tracking.
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.
Fig. M7