Sanyo HV-DX300A Service Manual page 49

FIg.5.5 Adjustment of the X-POSITION
F. PLAYBACK PHASE Adjustment(Fig. 5.6)
S/W PULSE TEST PIN
Test Point
ENVELOPE TEST PIN
Measurement Equipment OSILLOSCOPE
Adjustment
VR 595(PG SHIFTER)
PHASE GENERATOR(PG) SHIFTER determine the
VIDEO HEAD SWITCHING POINT when the TAPE is
played back. If an adjustment of the PHASE GENERA-
TOR(PG) SHIFTER is not done precisely, There can be a
HEAD SWITCHING NOISE or a VERTICAL JITTER
problem, vibration of the picture on the screen, not good
quality of picture in special play back.
a. Connect the PT01 on the MAIN CIRCUIT BOARD with
a PATH ADJ. FIXTURE.
b. Play back an ALIGNMENT TAPE
c. Connect the S/W PULSE TEST PIN on the PATH ADJ.
FIXTURE with a CHANNEL-1 SCOPE PROBE.
d. Connect the VIDEO OUT on the MAIN CIRCUIT
BOARD with a CHANNEL-2 SCOPE PROBE (1V/div).
e. Control the PG VOLUME until the time interval
between the SWITCHING PULSE and the V-SYNC
SIGNAL is within the 6.5H
Fig.5.6 Playback Phase Adjustment
MAIN CIRCUTE BOARD
MAIN CIRCUTE BOARD
MAIN CIRCUTE BOARD
0.5H as shown in Fig. 5.6.
±
G.Adjustment of the LINEARITY(Fig. 5.7)
S/W PULSE TEST PIN
Test Point
ENVELOPE TEST PIN
Measurement Equipment OSILLOSCOPE
VR CONTROL
Adjustment
S/T GUIDE ROLLER
a. Connect the PT01 on the MAIN CIRCUIT BOARD with
a PATH ADJ. FIXTURE.
b. Play back an ALIGNMENT TAPE
c. Connect the FIXTURE S/W PULSE TEST PIN on the
PATH ADJ. CHANNEL-1 SCOPE PROBE.
d. Connect the VIDEO OUT on the MAIN CIRCUIT
BOARD with a CHANNEL-2 SCOPE PROBE (1V/div).
e. Adjust the VR CONTROL on the ADJ. FIXTURE until
the ENVELOPE signal is maximum while play back the
ALIGNMENET TAPE.
f. Adjust the S/T GUIDE ROLLER until the envelope signal
waveforms of the entrance and exit sides are as shown in
Fig. 5-7.
a: Max Output of Envelope
b: Min Output of Envelope
FIg.5.7 Adjustment of Linearity
22
PATH ADJ. FIXTURE
PATH ADJ.FIXTURE
PATH ADJ.FIXTURE
TAPE TRANSPORT SECTION