Input/Output Levels And Impedance; Adjustment Sequence; Power Supply Check; Output Voltage Check (Ma-342 Board) - Sony SLV-789HF Service Manual

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2-1-5.

Input/Output Levels and Impedance

Video input: LINE IN
Input signal: 1 Vp-p, 75 ohms, unbalanced,
sync negative
Video output: LINE OUT
Output signal: 1 Vp-p, 75 ohms, unbalanced,
sync negative
Audio input: LINE IN
Input level: –7.5 dBs
(0 dBs= 0.775 Vrms)
Input impedance: more than 47 kilohms
Audio output:LINE OUT
Standard level: –7.5 dBs at load impedance 47
kilohms
Output impedance: less than 10 kilohms
2-1-6.

Adjustment Sequence

The adjustments should be performed in the following sequence.

Power Supply Check

Servo/Video System Adjustments
Audio System Adjustments
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2-2. POWER SUPPLY CHECK
2-2-1.

Output Voltage Check (MA-342 Board)

Mode
+30 V Check
Measurement point
Specified value
–11 V Check
Measurement point
Specified value
+6 V Check
Measurement point
Specified value
Mode
+12 V Check
Measurement point
Specified value
+5 V Check
Measurement point
Specified value
MTR12 V Check
Measurement point
Specified value
F Check
Measurement point
Q Q
3 6 7 1 3 1 5
Specified value
[Check Method]
1) Each of these supply voltages must meet its specified value.
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6-2
9 4 2 8
STANDBY
C627 '
31.0 – 39.0 V
C642 '
–29.5 to – 23.5 V
Corrector of Q607
5.65 to 6.25 V
E-E
IC601 pin 2
11.7 to 12.3 V
Emitter of Q603
4.8 to 5.4 V
Correcter of Q605
12.5 to 14.5 V
ND420 #∞ to 1
0 5 8 2 9 9 4
2.0 to 5.0V
m
9 9
2 8 9 9