F. PLAYBACK PHASE ADJUSTMENT (See Fig. 5-6)

TEST POINTS

S/W PULSE TEST PIN

PATH ADJ. FIXTURE

 

 

VIDEO OUT

MAIN CIRCUIT BOARD

 

 

 

 

MEASURING EQUIPMENT

OSCILLOSCOPE

 

 

 

 

ADJUSTMENT

VR595 (PG SHIFTER)

MAIN CIRCUIT BOARD

 

 

 

 

 

 

Phase generator (PG) shifter decides the VIDEO HEAD switching point when a TAPE is played back.

In case the Phase generator (PG) shifter isn't correctly tuned, HEAD switching noise or vertical jitter may occur.

a. Connect the PATH ADJ. FIXTURE to PT01 of the MAIN CIRCUIT BOARD.

b. Play the ALIGNMENT TAPE (COLOR BAR SIGNAL OR MONOSCOPE SIGNAL)

c. Connect the channel-1 scope probe to the S/W PULSE TEST PIN of the PATH ADJ. FIXTURE. d. Connect the channel-2 scope probe(1V/div.) to the VIDEO OUT of the MAIN CIRCUIT BOARD. e. Play back the ALIGNMENT TAPE.

f. Adjust the PG volume for time interval of 6.5H±0.5H between switching pulse and V-sync signal.

Fig. 5-6 PLAYBACK PHASE ADJUSTMENT

31

Page 32
Image 32
Daewoo K3050MECHA service manual Playback Phase Adjustment See Fig