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3.2
Servo circuit
3.2.1 Switching point
•
Signal
(A1)
Stairstep signal
•
(A2)
Alignment tape(SP, stairstep, PAL) [MHPE]
•
(A3)
Alignment tape(SP, stairstep, NTSC) [MHP]
•
Mode
(B)
PB
•
TBC: OFF
•
Equipment
(C)
Oscilloscope
•
Measuring point (D1)
VIDEO OUT terminal (75Ø terminated)
•
(D2)
TP106 (PB. FM)
•
External trigger
(E)
TP111 (D.FF)/slope : –
•
Adjustment part
(F)
Jig RCU: Code "51" or "52"
•
Specified value
(G)
8.0 ± 0.5H [MHPE]
•
7.5 ± 0.5H [MHP]
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
(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.
(7) Play back the signal (A1) of the alignment tape (A3).
(8) Repeat steps (2) to (6).
Trigger point
Switching point
Fig. 3-2-1a
3.2.2 Slow tracking preset
•
Signal
(A1)
Ext. input
•
(A2)
Color (colour) bar signal [PAL]
•
Mode
(B1)
VHS SP
•
(B2)
VHS LP
•
Measuring point (D)
TV-Monitor
•
Adjustment part
(F)
Jig code "71" or "72"
•
Specified value
(G)
Minimum noise
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
(1) Record the signal (A2) in the mode (B1), and play back
the recorded signal.
(2) Set the VCR to the manual tracking mode.
(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.
V.sync
V. rate
Switching point
3.3 Video circuit
3.3.1 D/A level
•
Signal
(A1)
Ext. S-input / Ext. input
•
(A2)
Color (colour) bar signal [PAL]
•
(A3)
S-VHS tape
•
Mode
(B)
S-VHS
•
EE
•
Equipment
(C)
Oscilloscope
•
Measuring point (D)
Y OUT terminal (75Ø terminated)
•
Adjustment part
(F)
VR1401 (D/A LEVEL ADJ)
[3D TBC/2M board]
•
Specified value
(G)
1.00 ± 0.015 Vp-p (reference value)
(Note)
(1) Insert the cassette tape (A3) to enter the mode (B).
(2) Observe the Y OUT waveform at the measuring point (D).
(3) Check the Y level value when the External S-input (Y/C
separated video signal).
(4) Switch the input signal to the External input (composite
video signal), and adjust the adjustment part (F) so that
the Y level becomes the same value observed in step (3).
Note:
• The specified value (G) is just a reference value to be
obtained when the External S-Video (Y/C separated
video) signal is input. In actual adjustment, set it to
the value observed in step (3).
H. rate
Fig. 3-3-1a
3.3.2 EE Y/PB Y (S-VHS/VHS) level
•
Signal
(A1)
Ext. input
•
(A2)
Color (colour) bar signal [PAL]
•
Mode
(B1)
EE
•
(B2)
S-VHS SP
•
(B3)
VHS SP
•
Equipment
(C)
Oscilloscope
•
Measuring point (D)
Y OUT terminal (75Ø terminated)
•
EVR mode
(F1)
Jig code "57"
•
EVR address
(F2)
A : 11
•
(F3)
Jig code "21" twice
•
(F4)
Jig code "18" or "19" (Channel +/-)
•
Specified value
(G)
1.00 ± 0.03 Vp-p
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
(1) Set the VCR to the mode (B1).
(2) Observe the Y OUT waveform at the measuring point (D).
(3) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(4) Set the EVR address to (F2) by transmitting the code (F3)
from the Jig RCU.
(5) Transmit the code (F4) from the Jig RCU to adjust so that
the Y level of the Y OUT waveform becomes the speci-
fied value (G).
(6) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
Y level
D/A level
3-2
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