Sony KV-21V4A Service Manual ▷ View online
– 62 –
[ Specified Input/Output Level Impedance ]
Input/Output terminal
Video input
Pin jack
Input signal : 1Vp-p, 75
Input signal : 1Vp-p, 75
Ω
, unbalanced
Sync negative
VIDEO LINE OUT Pin jack
Output siganl : 1Vp-p, 75
Ω
, unbalanced
Sync negative
AUDIO LINE IN
Pin jack
Input level
Input level
: -7.5dBs
(0dBs=0.775Vrms)
Input impedance : More than 47k
Ω
AUDIO LINE OUT Pin jack
Specified output : -7.5dBs
At 47k
Ω
loaded.
Load impedance : More than 10k
Ω
[ Adjustment Sequence ]
Make the electrical adjustment in the following sequences.
Video system adjustment
Audio system adjustment
Servo system adjustment
Tuner system adjustment
Checking power supply
Servo system adjustment
2-1. MA BOARD ADJUSTMENT
1. Recording bias adjustment
Mode
Recording and playback (SP mode)
Signal
400Hz, -27.5dBs
7kHz, -27.5dBs
Measurement
Audio level meter
Equipment
Adjustment
RV301
Element
Specified Value
0
±
2dB
Note : Tape path adjustment should have been completed.
1) Input signal of 400Hz, -27.5dBs.
2) Make recording.
3) Set the AUDIO LINE IN signal to 7kHz, -27.5dBs and
2) Make recording.
3) Set the AUDIO LINE IN signal to 7kHz, -27.5dBs and
make recording.
4) Playback a recorded portion and measure output levels
at 400Hz and 7kHz.
5) Confirm that the 7kHz playback signal level is within a
range of 0
±
2dB against the 400Hz playback signal
level. When beyond this range, adjust RV301 and
repeat the step (1) through (5).
repeat the step (1) through (5).
MA BOARD
- component side -
RV301
RV652
VR002
IC501
RV502
REC C PAL
SYNC GATE
L005
REC BELL 2
L004
PB BELL
RV001
REC C SECAM
SWITCHING POSITION
AUDIO
BIAS
REC
BELL 1
L003
– 63 –
2-2. SERVO SYSTEM ADJUSTMENT
Switching position adjustment (MA board)
Mode
Playback
Siganl
Alignment tape, Stair step
Measurement Point
CH : Pin
of CN802 (MA)
CH : Pin
of CN801 (MA)
Measurement
Oscilloscpe
Equipment
Adjustment
RV502
Element
Specified Value
416
±
32
µ
sec (6.5
±
0.5H)
Adjustment Method :
1) Press the tracking buttons and at a time.
2) Adjust for 416
2) Adjust for 416
±
32
µ
sec (6.5
±
0.5) using RV502.
Approx.
1 Vp-p
1 Vp-p
Approx.
5 Vp-p
5 Vp-p
V
V sync
Magnified
CH1
CH2
CH1
CH2
6.5
±
0.5H
(416
±
32
µ
sec)
Fig. 2-3 Switching position adjustment
[ Adjustment Spquences ]
1) ACE head adjustment
... See “ VHS MECHANICAL ADJUSTMENTMANUAL
MANUAL ”.
MANUAL ”.
2) Playback output level check.
1. ACE head adjustment
See “ VHS MECHANICAL ADJUSTMENTMANUAL
MANUAL ”.
MANUAL ”.
2. Playback output level check
Mode
Playback
Siganl
Alignment tape, 1 kHz (color bar)
portion
Measurement Point
AUDIO LINE OUT terminal
Measurement
Audio level meter
Equipment
Specified Value
-7.5
±
2 dBs
Confirmation Method :
1) Playback 1kHz portion and make sure that AUDIO
LINE OUT signal level is -7.5
±
2dBs.
2-3. AUDIO SYSTEM ADJUSTMENTS
[ Connection ]
Audio level meter
or distortion meter
or distortion meter
AUDIO LINE OUT
47k
VTR
AUDIO LINE IN
800
Ω
Attenuator
Audio oscillator
Fig. 2-4.
•Make adjustment in the SP mode.
2-4. REC CHROMA ADJUSTMENT
1) Input the PAL COLOUR BAR signal (2Vp-p).
2) Connect Oscilloscope to JL022.
3) Adjust for 150
2) Connect Oscilloscope to JL022.
3) Adjust for 150
±
10mVp-p (Red level) using RV652
(EE mode).
Red level
150 ± 10mVp-p
150 ± 10mVp-p
– 64 –
2-5. SECAM SYNC GATE ADJUSTMENT
(EE Mode)
1) Input the SECAM COLOUR BAR (2Vp-p).
2) Connect Oscilloscope to JL307 and JL033.
3) Adjust for 1.0
2) Connect Oscilloscope to JL307 and JL033.
3) Adjust for 1.0
±
0.2
µ
sec using VR002.
B MODEL ONLY ADJUSTMENT
2-9. PB BELL ADJUSTMENT (PB Mode)
1) Connect between GND and JL304.
2) Input the SECAM RF signal (400mVp-p).
3) Connect Oscilloscope to JL082
4) Adjust for both top and bottom to be flat using L004.
2) Input the SECAM RF signal (400mVp-p).
3) Connect Oscilloscope to JL082
4) Adjust for both top and bottom to be flat using L004.
2-8. SECAM REC CHROMA ADJUSTMENT
(EE Mode)
1) Input the SECAM COLOUR BAR (2Vp-p).
2) Connect Oscilloscope to JL303.
3) Adjust for 90mVp-p using VR001.
2) Connect Oscilloscope to JL303.
3) Adjust for 90mVp-p using VR001.
90mVp-p
JL303
JL082
Both top and bottom
to be flat
to be flat
2-6. REC BELL ADJUSTMENT (1) (EE Mode)
1) Input the SECAM COLOUR BAR (2Vp-p).
2) Connect Oscilloscope to JL084.
3) Adjust for 200mVp-p using L003.
2) Connect Oscilloscope to JL084.
3) Adjust for 200mVp-p using L003.
2-7. REC BELL ADJUSTMENT (2) (EE Mode)
1) Input the SECAM COLOUR BAR (2Vp-p).
2) Connect Oscilloscope to JL082.
3) Adjust for 70mVp-p using L005.
2) Connect Oscilloscope to JL082.
3) Adjust for 70mVp-p using L005.
1.0 ± 0.2µsec
JL033
JL307
200mVp-p
JL084
70mVp-p
JL082
2-10. SECAM DET ADJUSTMENT
(REC/PB Mode)
1) Input the SECAM COLOR BAR.
2) Connect Oscilloscope to pin! of IC051.
3) Adjust for 4.8
2) Connect Oscilloscope to pin! of IC051.
3) Adjust for 4.8
±
0.1 Vp-p using RV051.
4.8 ± 0.1 Vp-p
– 65 –
SECTION 3
INTERF
A
CE,
IC PIN FUNCTION DESCRIPTION
3-1. SYSTEM CONTROL-VIDEO BLOCK INTERFACE (MA BOARD IC501)
*1. 25Hz 50% duty pulse synchronizing with drum rotation.
*2. Normally “L” . “H” when the video signal is not detected.
*3. V period “H” pulse.
*4. “L” in the SP mode. Selected according to the recording mode.
*5. Selected according to the tape recording mode.
*2. Normally “L” . “H” when the video signal is not detected.
*3. V period “H” pulse.
*4. “L” in the SP mode. Selected according to the recording mode.
*5. Selected according to the tape recording mode.
*6. Composite sync signal (positive).
*7. “H” when menu screen or gray back screen.
*8. Selected by REC mode, “L” in the SP mode.
*9. “H” while APC is set.
*7. “H” when menu screen or gray back screen.
*8. Selected by REC mode, “L” in the SP mode.
*9. “H” while APC is set.
Signal
Mode
SP
LP
EP
SP
L
H
H
LP
L
L
H
V·PB
IC501
O
H
H
H
H
H
L
L
L
L
L
L
H
H
RF SW P (SW25)
IC501
O
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
Q VD/V MUTE
IC501
O
L
L
L
L
L
*2
*3
*3
*3
*3
*3
L
L
NA·SP
IC501
O
*4
*4
*4
*4
*4
*5
*5
*5
*5
*5
*5
*4
*4
LP
IC501
O
*8
*8
*8
*8
*8
*5
*5
*5
*5
*5
*5
*8
*8
REC·P
IC501
O
L
L
L
L
L
L
L
L
L
L
L
L
H
REC
IC501
O
L
L
L
L
L
L
L
L
L
L
L
H
H
V SYNC
IC501
I
*6
*6
*6
*6
*6
*6
*6
*6
*6
*6
*6
*6
*6
OSD MUTE
IC501
O
*7
*7
*7
*7
*7
*7
*7
*7
*7
*7
*7
*7
*7
CTL REC
IC501
O
L
L
L
L
L
L
L
L
L
L
L
H
L
NTSC
IC501
O
L
L
L
L
L
L
L
L
L
L
L
L
L
JOG
IC501
O
L
L
L
L
L
L
H
H
H
H
H
L
L
CRC SETTEI
IC501
O
L
L
L
L
L
L
L
L
L
L
L
*9
*9
TAPE
TAPE
PB ·
PICTURE SEARCH
REC ·
Signal
Pin No.
I/O
STOP
FF
REW
THREADING UNTHREADING
PB
PAUSE
SLOW
X2
CUE
REVIEW
REC
PAUSE
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