Sony SLV-798HF / SLV-998HF Service Manual ▷ View online
6-2
2-1-5. Input/Output Levels and Impedance
Video input:
LINE IN
Input signal: 1Vp-p, 75ohms, unbalanced,
sync negative
Input signal: 1Vp-p, 75ohms, unbalanced,
sync negative
Video output: LINE OUT
Output signal: 1Vp-p, 75ohms, unbalanced,
sync negative
sync negative
Audio input:
LINE IN
Input level: –7.5 dBs
(0dBs= 0.775Vrms)
Input impedance: more than 47 kilohms
Input level: –7.5 dBs
(0dBs= 0.775Vrms)
Input impedance: more than 47 kilohms
Audio output: LINE OUT
Standard level: –7.5dBs at load impedance 47
kilohms
Output impedance: less than 10 kilohms
kilohms
Output impedance: less than 10 kilohms
2-1-6. Adjustment Sequence
The adjustments should be performed in the following sequence.
2-2.
POWER SUPPLY CHECK
2-2-1. Output Voltage Check (MA-318 Board)
Mode
E-E
Measuring Instrument
Digital voltmeter
SW 12V Check
Measurement point
IC601 pin 2
Specified value
12.0
±
0.3V
MTR12V Check
Measurement point
Q605 C
Specified value
13.2
±
1.0V
SW5V Check
Measurement point
Q603 E
Specified value
5.1
±
0.3V
[Check Method]
1)
1)
Each of these supply voltages must meet its specified value.
Power Supply Check
Servo System Adjustments
Video System Adjustments
Audio System Adjustments
Tuner System Adjustments
6-3
2-3.
SERVO SYSTEM CHECK
Unless otherwise specified, set the switches to the following
positions.
positions.
•
INPUT SELECT switch ............................. LINE or LINE 1
(Remote commander)
•
TAPE SPEED
switch ...................... SP (Remote commander)
2-3-1. RF Switching Position/
AF Switching Position Adjustments
(MA-318 Board)
(MA-318 Board)
[Adjustment Purpose]
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the link will appear on the screen and
the screen will be disrupted, etc.
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the link will appear on the screen and
the screen will be disrupted, etc.
Mode
Playback
Signal
Alignment tape: SP color bar portion
Measurement point
CH1: Video LINE OUT
(RF switching position)
CN341 pin 1 (HF ADJ)
(AF switching position)
CN341 pin 1 (HF ADJ)
(AF switching position)
CH2: CN261 pin 3 (RF SWP)
Measuring instrument
Oscilloscope
Specified value
6.5
±
0.5H (410
±
32
µ
sec)
[Adjustment Method]
1)
1)
Short-circuit between JS161 and ground for about 1 second to
activate the RF switching position adjustment mode.
activate the RF switching position adjustment mode.
2)
Check that “AP” is indicated on FL display.
3)
Using the channel + and – buttons, adjust to 410
±
32
µ
sec (6.5
±
0.5H).
4)
Press the PAUSE button. (Adjustment is over for mono models.)
5)
The set goes to the AF switching position adjustment mode.
Fig. 6-2-3.
6)
Check that “AH” is indicated on FL display.
7)
Using the channel + and – buttons, minimize a chipped portion.
At this time, confirm that a noisy sound is not heard.
At this time, confirm that a noisy sound is not heard.
8)
Press the PAUSE button.
9)
Check that “AH” indication is disappeared. When it is not
disappeared, repeat from the item 1).
disappeared, repeat from the item 1).
10) Press the STOP button.
11) Press the EJECT button.
11) Press the EJECT button.
Fig. 6-2-4.
CN261 pin
3
6.5
±
0.5H
CH1
CH2
CH1
CH2
Enlarrgement
Vertical sync. signal
Approx.
5Vp-p
5Vp-p
Approx.
1Vp-p
1Vp-p
V
CH2
RF SWP
CN261 pin
RF SWP
CN261 pin
3
CH1
REC AFM
CN341
pin
REC AFM
CN341
pin
1
OK
NG
Should be minimized
RF signal dropout
6-4
2-4-2. SYNC AGC Check (MA-318 Board)
Mode
E-E
Signal
Color bar
Measurement point
IC201 pin #•
Measuring instrument
Oscilloscope
Specified value
A=2.10
±
0.10Vp-p
[Check Method]
1)
1)
Check that the Video signal level (A) satisfies the specified
value.
value.
Fig. 6-2-6.
2-4-3. Recording Y Level Check (MA-318 Board)
Mode
E-E (SP)
Signal
No-signal
Measurement point
IC201 pin !•
Measuring instrument
Oscilloscope
Specified value
A=290
±
70mVp-p
[Check Method]
1)
1)
Check that the recording RF signal satisfies the specified value.
Fig. 6-2-8.
2-4.
VIDEO SYSTEM CHECKS AND ADJUSTMENT
For the video system checks, follow the checking procedures given
below as a rule. The color bar video signal supplied from the pattern
generator is used as the video input signal for the video system
adjustment of the recording mode. Check that the signal satisfies
the specified value designated in the “Check of input signal” (Fig.
6-2-2)
Unless otherwise specified, set the switches to the following
positions.
below as a rule. The color bar video signal supplied from the pattern
generator is used as the video input signal for the video system
adjustment of the recording mode. Check that the signal satisfies
the specified value designated in the “Check of input signal” (Fig.
6-2-2)
Unless otherwise specified, set the switches to the following
positions.
•
INPUT SELECT switch ............................. LINE or LINE 1
(Remote commander)
•
TAPE SPEED
switch ...................... SP (Remote commander)
[Checking Sequence]
1)
1)
X’tal OSC Check
2)
SYNC AGC Check
3)
Recording Y Level Check
4)
Recording Chroma Level Check
5)
Playback Level Check
2-4-1. X’tal OSC Check (MA-318 Board)
Mode
Playback
Signal
Alignment tape: SP Color bar portion
Measurement point
IC201 pin %§
Measuring instrument
Oscilloscope and Frequency counter
Specified value
3,579,545
±
70Hz
Note:
A frequency counter should be connected through a buffer
amplifier (oscilloscope, etc.) having a high impedance and
a low capacitance.
a low capacitance.
[Check Method]
1)
1)
Check that the oscillation frequency satisfies the specified value
and that the oscillation voltage is 500
and that the oscillation voltage is 500
±
200mVp-p.
Fig. 6-2-5.
500
±
200mVp-p
3,579,545
±
70Hz
White (100%)
H
A
A
6-5
2-5.
AUDIO SYSTEM ADJUSTMENT
• For the adjustment of the audio system, perform in the SP mode
if there is no special notes. Use the alignment tape.
[Connecting Instruments]
Fig. 6-2-11.
• Adjust in the SP mode if there is no special indications.
• Perform the adjustment setting the switch on the following
• Perform the adjustment setting the switch on the following
positions.
•
INPUT SELECT switch .............................. LINE or LINE 1
(Remote commander)
[Adjustment Method]
1.
1.
ACE head adjustment.....Refer to the VHS mechanical
adjustment manual (S MECHANISM)(9-921-647-11).
adjustment manual (S MECHANISM)(9-921-647-11).
2.
E-E output level check
3.
Overall Output level and distortion factor check
4.
Overall noise level check.
2-5-1. ACE Head Adjustment
Refer to the VHS mechanical adjustment manual
(S
MECHANISM)(9-921-647-11).
2-5-2. E-E Output Level Check
Mode
E-E
Signal
400Hz, –7.5dBs : CJ570
Measurement point
CJ570
Measuring instrument
Audio level meter
Specified value
–7.5
±
2dBs
[Check Method]
1)
1)
Input signal of 400Hz and –7.5dBs to the CJ461 L/R.
2)
Check that the audio output level is –7.5
±
3dBs.
2-4-4. Recording Chroma Level Check
(MA-318 Board)
Mode
Recording (SP)
Signal
Color bar
Measurement point
IC201 pin !¢
Measuring instrument
Oscilloscope
Specified value
A=380
±
70mVp-p
[Check Method]
1)
1)
Confirm the amplitude of recording chroma level becomes the
specified value.
specified value.
Fig. 6-2-9.
2-4-5. Playback Level Check (MA-318 Board)
Mode
Playback
Signal Alignment
Alignment tape : SP mode color bar
portion
portion
Measurement point
Video LINE OUT terminal
Measuring instrument
Oscilloscope
Specified value
A=1.0
±
0.1Vp-p (75
Ω
terminated)
[Check Method]
1)
1)
Check that the playback level satisfies the specified value.
Fig. 6-2-10.
A
White (100%)
H
A
VTR
Audio line OUTPUT L/R
Audio line INPUT L/R
Audio
oscillator
Attenuator
600
Ω
Audio level
meter
or
distortion
meter
47 k
Ω
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