Input/Output Levels And Impedance; Adjustment Sequence; Power Supply Check; Output Voltage Check (Ma-405 Board) - Sony LX40 Service Manual

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
2-2. POWER SUPPLY CHECK
2-2-1.

Output Voltage Check (MA-405 Board)

Mode
+30 V Check
Measurement point
Specified value
–11 V Check
Measurement point
Specified value
D+6 V Check
Measurement point
Specified value
Mode
Measuring Instrument
SW+12 V Check
Measurement point
Specified value
SW+5 V Check
Measurement point
Specified value
MTR12 V Check
Measurement point
Specified value
F Check
Measurement point
Specified value
[Check Method]
1) Each of these supply voltages must meet its specified value.
6-2
STANDBY
C671 3
31.0 to 39.0 V
Anode of D420
–12.5 to – 9.5 V
Collector of Q674
5.56 to 6.25 V
E-E
Digital voltmeter
IC660 pin 2
11.7 to 12.3 V
Emitter of Q662
4.8 to 5.4 V
Collector of Q600
12.5 to 14.5 V
ND420 e; to 1
2.0 to 5.0V