Auto Picture Initial Setting; Audio Circuit; Audio Rec Fm; Demodulator Circuit - JVC HR-S9800U Service Manual

3.3.6 AUTO PICTURE initial setting

•
Signal (A1) Ext. input
•
(A2) Video: Optional
•
(A3) VHS tape
•
EE ¥ Auto adjust (SP/EP REC ¥ PB)
Mode (B)
•
Adjustment part (F) Jig RCU : Code "58"
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Specified value (G) STOP mode
•
Adjustment tool (H) Jig RCU [PTU94023B]
(1) Insert the cassette tape (A3).
(2) Set the VCR to the Auto adjust mode by transmitting the
code (F) from the Jig RCU. When the VCR enters the
stop mode, the adjustment is completed. When the VCR
enters the eject mode, repeat steps (1) to (2) again.

3.4 AUDIO CIRCUIT

Notes:
• This adjustment should be done after the "REC color
(colour) level adjustment" for the video circuit has
been completed.
• GND (Ground) should be taken from the Tuner shield
case.

3.4.1 Audio REC FM

•
Signal (A1) Ext. input
•
(A2) Audio: No signal
•
(A3) Video: Color (colour) bar signal [NTSC]
•
Mode (B) S-VHS EP
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Equipment (C) Oscilloscope
•
Measuring point (D) TP2253 (A. FM)
•
External trigger (E) TP111 (D.FF)
•
EVR mode (F1) Jig RCU: Code "57"
•
EVR address (F2) A: 30 (Press remote controller "3"
and "0" keys.)
•
Specified value (G1) 500 ± 100 mVp-p
•
(G2) More than 350 mVp-p
•
Adjustment tool (H) Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Apply the external trigger signal to D.FF (E) to observe
the Audio PB FM waveform at the measuring point (D).
(2) Record the signal (A3) with no audio signal input in the
mode (B), 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) If the A.PB FM level is not within the specified value (G1),
perform the adjustment in a following procedure.
(5) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(6) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(7) Adjust with the channel buttons (+, –) on the VCR (or on
the remote controller) so that the A.PB FM level of the
higher channel level becomes the specified value (G1).
(Adjust before recording, then confirm it by playing back.)
(8) If the specified value (G1) is not obtained, adjust with the
channel buttons (+, –) so that the waveform level of the
lower channel level becomes the specified value (G2).
(Adjust before recording, then confirm it by playing back.)
(9) 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.)
Specified
value (G2)
V. rate
Fig. 3-4-1a
3.5

DEMODULATOR CIRCUIT

Notes:
• Unless otherwise specified in this demod circuit ad-
justments, all measuring points and adjustment parts
are located on the Demod board.
• Unless otherwise specified,set an audio multiplex TV
signal generator as follows;
RF signal : 70 dBµ / 75 Ø , color bar 87.5% modulation.

3.5.1 Input level

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Signal (A) RF signal (Audio: mono 300 Hz)
•
Mode (B) Tuner
•
EE
•
Equipment (C) Audio level meter
•
Measuring point (D) IC1501 pin 26
•
EVR mode (F1) Jig RCU : Code "57"
•
EVR address (F2) A : 20 (Press remote controller "2"
and "0" keys.)
•
Specified value (G) 500 ± 10 mVrms
•
Adjustment tool (H) Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Set an audio signal mode of the RF signal generator to
mono 300 Hz.
(2) Connect the equipment (C) to 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 pressing the button of
the digit-key remote controller.
(5) Adjust with the channel buttons (+,–) on the VCR (or on
the remote controller) so that the level of the measuring
point (D) becomes the specified 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.)

3.5.2 Stereo VCO

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Signal (A) No signal
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Mode (B) Tuner
•
EE
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Equipment (C) Frequency counter
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Measuring point (D1) IC1501 pin 26
•
Short point (D2) C1505(–) terminal
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EVR mode (F1) Jig RCU : Code "57"
•
EVR address (F2) A : 21 (Press remote controller "2"
and "1" keys.)
•
Specified value (G) 15.73 ± 0.1 kHz
•
Adjustment tool (H) Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Connect the short wire between the short point (D2) and
the GND (Ground).
(2) Connect the equipment (C) to the measuring point (D1).
Specified
value (G1)
Audio REC FM
3-5