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3.3 Video circuit
3.3.1 D/A level
•
Signal
(A1)
Ext. S-input / Ext. input
•
(A2)
Color (colour) bar signal [NTSC]
•
(A3)
S-VHS tape
•
Mode
(B)
S-VHS
•
EE
•
Equipment
(C)
Oscilloscope
•
Measuring point (D)
VIDEO OUT terminal (75Ø terminated)
•
Adjustment part
(F)
VR1401 (D/A LEVEL ADJ)
[3D Digital/4M 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 VIDEO 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 [NTSC]
•
(A3)
S-VHS
•
Mode
(B1)
EE
•
(B2)
S-VHS SP
•
(B3)
VHS SP
•
Equipment
(C)
Oscilloscope
•
Measuring point (D)
TP7101(Y OUT) [Main board]
•
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)
2.05 ± 0.05 Vp-p
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
(1) Insert the cassette tape (A3) to enter 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.
3-3
Y level
D/A level
(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.)
(7) Record the signal (A2) in the mode (B2), and play back
the recorded signal.
(8) Set the VCR to the manual tracking mode.
(9) Repeat steps (2) to (6) in the mode (B2).
(10) Record the signal (A2) in the mode (B3), and play back
the recorded signal.
(11) Set the VCR to the manual tracking mode.
(12) Repeat steps (2) to (6) in the mode (B3).
H. rate
Fig. 3-3-2a
3.3.3 REC color (colour) level
•
Signal
(A1)
Alignment tape(S-VHS, SP/EP, Color(colour)
bar) [MH-1H]
•
(A2)
Ext. input
•
(A3)
Color (colour) bar signal [NTSC]
•
Mode
(B1)
S-VHS SP
•
(B2)
S-VHS EP
•
Equipment
(C)
Oscilloscope
•
Measuring point (D1)
TP106 (PB-FM) [Main board]
•
(D2)
PB color (colour) output of the LPF
•
External trigger
(E)
TP111 (D.FF)
•
EVR mode
(F1)
Jig code "57"
•
EVR address
(F2)
A : 02
•
(F3)
Jig code "20" and "22"
•
(F4)
Jig code "18" or "19" (Channel +/-)
•
Specified value
(G)
SP: "B" x 125 ± 5%
•
EP: "B" x 125 ± 5%
•
Adjustment tool
(H1)
Jig RCU [PTU94023B]
(H2)
• LPF [PTU93006]
39 µH
1 kØ
PB-FM
120 pF
Fig. 3-3-3a LPF
(1) Connect the adjustment tool (H2) to the measuring point
(D1).
(2) Apply the external trigger signal to D.FF (E) to observe the
PB color (colour) waveform at the measuring point (D2).
(3) Play back the signal (A3) in the mode (B1) of the align-
ment tape (A1).
(4) Set the VCR to the manual tracking mode.
(5) Adjust tracking so that the PB color (colour) waveform
becomes maximum. Make a note of the higher PB color
(colour) level as "B" at this time.
(6) Record the signal (A3) in the mode (B1), and play back
the recorded signal.
Y level
EE/PB Y level
(See Fig. 3-3-3a.)
180 µH
629 [kHz]
PB COLOR
(PB COLOUR)
180 pF
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