31
6. Playback Phase Adjustment (Fig. 14)
Test Points:
PT01 Pin3
Main
Video Out Jack
Rear Panel
Observe:
Oscilloscope
Adjust:
VR595 (PG Shifter)
Main
The Phase Generator (PG) Shifter determines the video head
switching point during playback. Wrong adjustment of the PG
shifter may cause the head switching noise in the picture and/or
vertical jitter.
1). Play Back the Alignment Tape (color bar signal or mono-
scope signal).
2). Connect the channel-1 scope probe (1V/div.: 50psec/div.) to
PT01 pin3. Trigger the scope on channel-1.
3). Connect the channel-2 scope prove (1V/div.) to the video out
jack.
4). Set the scope to (–) slope an adjust the PG Shifter control
(VR595) so that the trailing edge of the SW30Hz pulse is
placed 6.5H±0.5H(horizontal) lines before the start of the
vertical (horizontal) lines before the start of the vertical sync
pulse.
7. Linearity Adjustment (Fig. 15)
Test Points:
CTL Pulse Test Pin
Path Adj. Fixture
Envelope Test Pin
Path Adj. Fixture
Observe:
Oscilloscope
Adjust:
VR Control
Path Adj. Fixture
S/T Guide Rollers
Transport Mech.
1). Connect the Path Adj. Fixture to PT01 on the Main circuit
board.
2). Play back the Alignment tape (color bar signal).
3). Connect the channel-1 scope probe to the CTL pulse test pin
on the Path Adj. Fixture.
4). Connect the channel-2 scope probe to the envelope test pin
on the Path Adj. Fixture. Externally trigger the scope using
the SW pulse test pin on the Path Adj. Fixture.
5). Adjust the VR Control on the Path Adj. Fixture so the enve-
lope (FM) signal of the Aligment tape is maximum.
6). Adjust the S/T guide rollers so that the envelope (FM) signal
waveform at the entrance and exit sides are as shown
in Fig. 1
8. Fine Adjustment of Envelopes at Drum Entrance/Exit
Parts (Fig. 16 & 17)
Test Points:
CTL Pulse Test Pin
Path Adj. Fixture
Envelope Test Pin
Path Adj. Fixture
Observe:
Oscilloscope
Adjust:
VR Control
Path Adj. Fixture
S/T Guide Rollers
Transport Mech.
1).Connect the Path Adj. Fixture to PT01 on the Main circuit
board.
2). Play back the alignment tape (color bar signal).
3). Connect the channel-1 scope probe to the CTL pulse test pin
on the Path Adj. Fixture.
4). Connect the channel-2 scope probe to the envelope test pin
on the Path Adj. Fixture. Externally trigger the scope using
the SW pulse test pin on the Path Adj. Fixture.
5). Adjust the VR Control on the Path Adj. Fixture CCW and
CW and confirm that the envelope waveform changes uni-
formly and remains flat throughout the overall range.
6). If the envelope is not uniform, slightly adjust the S/T Guide
Rollers to correct the envelope.
Fig. 13 X-Axis Position Adjustment
Fig. 14 Playback Phase Adjustment
Fig. 15 Linearity Adjustment
Summary of Contents for DV-K784N-JJ
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Page 100: ...99 POWER SUPPLY SCHEMATIC DIAGRAM FREE VOLTAGE K884NY SJ M K884NZ SJ M K884NZ SG M...
Page 102: ...101 PRE AMP SCHEMATIC DIAGRAM K884N K784N 804N Hi Fi PREAMP SCHEMATIC DIAGRAM REV 1 97 2 5...
Page 103: ...102 VIDEO AUDIO SCHEMATIC DIAGRAM K884N K784N K804N...
Page 104: ...103 PIF MPX SCHEMATIC DIAGRAM K884N K784N K804N Hi Fi PIF MPX SCHENATIC DIAGRAM REV 1 97 2 5...
Page 105: ...104 TIMER SYSCON SCHEMATIC DIAGRAM K884N K784N K804N...
Page 106: ...105 Hi Fi AUDIO SCHEMATIC DIAGRAM K884N K784N K804N Hi Fi AUDIO SCHEMATIC DIAGRAM REV 1 97 2 5...
Page 107: ...106 POWER SUPPLY BLOCK DIAGRAM FREE VOLTAGE K884NY SJ M K884NZ SJ M K884NZ SG M...
Page 108: ...107 POWER SUPPLY BLOCK DIAGRAM 120V ONLY K884N SJ K884N JJ K884N SG K784N SJ K784N JJ K784N SG...
Page 109: ...108 PRE AMP BLOCK DIAGRAM K884N K784N K804N Hi Fi PREAMP BLOCK DIAGRAM REV 1 97 2 5...
Page 110: ...109 VIDEO AUDIO BLOCK DIAGRAM K884N K784N K804N Hi Fi VIDEO BLOCK DIAGRAM REV 1 97 2 5...
Page 111: ...110 PIF MPX BLOCK DIAGRAM K884N K784N K804N Hi Fi PIF MPX BLOCK DIAGRAM REV 1 97 2 5...
Page 113: ...112 Hi Fi AUDIO BLOCK DIAGRAM K884N K784N K804N AUDIO BLOCK DIAGRA REV 1 97 2 5...
