Video Circuit; D/A Level; Ee Y Level; Pb Y Level (S-Vhs / Vhs) - JVC HR-S9800U Service Manual

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 level

•
Signal (A1) Ext. input
•
(A2) Color (colour) bar signal [NTSC]
•
Mode (B) EE
•
Equipment (C) Oscilloscope
•
Measuring point (D) Y OUT terminal (75Ø terminated)
•
EVR mode (F1) Jig RCU: Code "57"
•
EVR address (F2) A:11 (Press remote controller "1" key twice)
•
Specified value (G) 1.00 ± 0.03 Vp-p
•
Adjustment tool (H) Jig RCU [PTU94023B]
• Digit-key remote controller
(1) Observe the Y OUT waveform at the measuring point (D).
(2) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(3) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(4) Adjust with the channel buttons (+, –) on the VCR (or on
the remote controller) so that the Y level of the Y OUT
waveform becomes the specified value (G).
(5) 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
H. rate
Fig. 3-3-2a

3.3.3 PB Y level (S-VHS / VHS)

•
Signal (A1) Ext. input
•
(A2) Color (colour) bar signal [NTSC]
•
Mode (B1) S-VHS SP
•
(B2) VHS SP
•
Equipment (C) Oscilloscope
•
Measuring point (D) Y OUT terminal (75Ø terminated)
•
EVR mode (F1) Jig RCU: Code "57"
•
EVR address (F2) A:11 (Press remote controller
"1" key twice)
•
Specified value (G) 1.00 ± 0.03 Vp-p
•
Adjustment tool (H) Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Observe the Y OUT waveform at the measuring point (D).
(2) Record the signal (A2) in the mode (B1), and play back
the recorded signal.
(3) Press the channel buttons (+, –) simultaneously to enter
the manual tracking mode. This also brings tracking to
the center (centre).
(4) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(5) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(6) Adjust with the channel buttons (+, –) on the VCR (or on
the remote controller) so that the Y level of the Y OUT
waveform becomes the specified value (G).
(7) 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.)
(8) Repeat steps (2) to (7) in the mode (B2).
H. rate
Fig. 3-3-3a
Y level
EE Y level
Y level
PB Y level
3-3