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3.2
Servo circuit
3.2.1 Switching point
Signal
Mode
Equipment
Measuring point (D1)
External trigger
Adjustment part
Specified value
Adjustment tool
(1) Play back the signal (A1) of the alignment tape (A2).
(2) Apply the external trigger signal to D.FF (E) to observe
the VIDEO OUT waveform and V.PB FM waveform at the
measuring points (D1) and (D2).
(3) Set the VCR to the manual tracking mode.
(4) Adjust tracking so that the V.PB FM waveform becomes
maximum.
(5) Transmit the code (F) from the Jig RCU to adjust so that
the trigger point of the VIDEO OUT waveform is changed
from the trailing edge of the V.sync signal becomes the
specified value (G).
(6) Set the VCR to the stop mode or eject mode.
Trigger point
3.2.2 D-VHS switching point
Signal
Mode
Equipment
Measuring point (D)
External trigger
Adjustment part
Specified value
Adjustment tool
(1) Play back the signal (A1) of the alignment tape (A2).
(2) Apply the external trigger signal to D.FF (E) to observe
the D-VHS envelope waveform at the measuring point
(D).
(3) Set the VCR to the manual tracking mode.
(4) Adjust tracking so that the D-VHS envelope waveform
becomes maximum.
•
(A1)
Stairstep signal
•
(A2)
Alignment tape(SP, stairstep, NTSC) [MHP]
•
(B)
PB
•
TBC: OFF
•
(C)
Oscilloscope
•
VIDEO OUT terminal (75Ø terminated)
•
(D2)
TP106 (PB-FM) [Main board]
•
(E)
TP111 (D.FF)/slope : –
•
(F)
Jig RCU: Code "51" or "52"
•
(G)
8.0 ± 0.5H
•
(H)
Jig RCU [PTU94023B]
Switching point
Fig. 3-2-1a
Switching point
•
(A1)
Color (colour) bar
•
(A2)
(STD)
Alignment tape [MD-1]
•
(A3)
(HS)
Alignment tape [MD-1H]
•
(B1)
PB
•
TBC: OFF
•
(B2)
D-VHS STD
•
(B3)
D-VHS HS
•
(C)
Oscilloscope
•
(STD)
TP606 (PB DATA1)
•
(HS)
TP616 (PB DATA2)
•
(E)
(STD)
TP111 (VIDEO/STD/HS1 FF)
•
(HS)
TP112 (A/HS2 FF)
•
(F)
Jig RCU: Code "51" or "52"
•
(G)
230 ± 20µsec
•
(H)
Jig RCU [PTU94023B]
Published in Heiloo Holland
(5) Transmit the code (F) from the Jig RCU to adjust so that
the duration "a" from the waveform end (Hi/Low switch-
ing point of D.FF) to the rising edge of subcode area be-
comes the specified value (G).
(6) Set the VCR to the stop mode or eject mode.
(7) Play back the signal (A1) of the alignment tape (A3).
(8) Repeat steps (2) to (6) in the mode (B3).
D-VHS
envelope
3.2.3 Slow tracking preset
Signal
Mode
Measuring point (D)
Adjustment part
V.sync
Specified value
Adjustment tool
(1) Record the signal (A2) in the mode (B1), and play back
the recorded signal.
(2) Set the VCR to the manual tracking mode.
V. rate
(3) Set the VCR to the FWD slow (+1/6x) mode.
(4) Transmit the code (F) from the Jig RCU to adjust so that
the noise bar becomes the specified value (G) on the TV
monitor in the slow mode.
(5) Set the VCR to the Stop mode.
(6) Confirm that the noise bar is (G) on the TV monitor in
the slow mode.
(7) Repeat steps (3) to (6) in the REV slow (–1/6x) mode.
(8) Repeat steps (1) to (7) in the mode (B2).
Note:
• For FWD slow (+1/6x) playback, transmit the code "08"
from the Jig RCU to enter the slow playback mode, and
transmit the code "D0" for REV slow (–1/6x) mode.
a
Sub code area
End of waveform (D.FF signal Hi/Low switching point)
Fig. 3-2-2a
D-VHS switching point
•
(A1)
Ext. input
•
(A2)
Color (colour) bar signal [NTSC]
•
(B1)
VHS SP
•
(B2)
VHS EP
•
TV-Monitor
•
(F)
Jig code "71" or "72"
•
(G)
Minimum noise
•
(H)
Jig RCU [PTU94023B]
29/11/2016
3-2
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