Audio Processing - Input Stages - Sony XM-1502SX Training Manual

Operational test
To prove the device is functional:
1. Connect the negative lead of the ohmmeter to the SOURCE lead.
2. Touch the ohmmeter positive lead to the gate to pre-charge it.
3. Connect the ohmmeter positive lead to the DRAIN.
If the device is good, you will get a resistance reading of about 400-1k ohms.
Audio Processing
Refer to Figure 1-6 and Table 1-3 for the location and signal output of each audio stage. The left channel is
shown but the right channel is similar. With all the filter controls set at mid rotation and a 1Vp-p 1kHz signal input,
the signal levels are shown in table 1-3 as they pass through the op-amp stages. S901 filter switch is OFF. The
audio ground is used (at the input jack or speaker output).
CNJ801-1
INPUT
L
IC102(2/2)
5
5
6
RV103-1
LOW
BOOST
Location
IC101/pin 3
IC101/pin 1
IC101/pin 6
IC101/pin 7
IC102/pin 5
Conditions: 1Vp-p, 1kHz input, Controls at mid rotation, switches = OFF.
– Input Stages
IC101(1/2)
PRE-AMP
+
3
-
2
RV801-1
H.L.F.
FILTER
7
IC104(2/2)
LOW
IC104(1/2)
BOOST
LINE AMP.
+
7 3
-
2
Q101
LEVEL
SHIFT
FIGURE 1-6 - LEFT CHANNEL INPUT AUDIO STAGES
Table 1-3 - Audio Signal Levels
Level
0.4 Vp -p IC102/pin 7
1 Vp-p IC102/pin 2
0 IC102/pin 1
1 Vp-p IC103/pin 6
0.4 Vp -p IC103/pin 7
1
RV101-1 FILTER
IC102(1/2)
RV801-2
L.P.F.
FILTER
2 1
Q102
LINE SWITCH
+
1
-
Q801, 802
LINE SWITCH
RV104-1
CONTROL
LEVEL
Location Level
1 Vp-p
0
0.1 Vp-p
0
20 mV
8
1. Car Power Amplifier
IC101(2/2)
PRE-AMP
-
6
7
+
5
IC103(2/2)
L.P.F.
6 7
TO DIFFERENTIAL
AMPLIFIER STAGE
IC901
GND.
ISOL.
Location
IC104/pin 5 0.7 Vp-p
IC104/pin 7 1.3 Vp-p
IC104/pin 3 1.3 Vp-p
IC104/pin 1 6 Vp-p
Q102/any 6 Vp-p
LPF
S901-1
OFF
FILTER
HPF
Q903
POWER
ON/OFF
3A125 1456 11/12/02
Level