Note For Printed Wiring Boards And Schematic Diagrams - Sony SPP-A941 Service Manual

5-3.

NOTE FOR PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS

Note on Printed Wiring Board:
• X : parts extracted from the component side.
• Y : parts extracted from the conductor side.
• b : Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
• : connected by carbon pattern.
Caution:
Pattern face side: Parts on the pattern face side seen from
(Side B) the pattern face are indicated.
Parts face side: Parts on the parts face side seen from
(Side A) the parts face are indicated.
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ω and
1 / W or less unless otherwise
4
specified.
• % : indicates tolerance.
• C : panel designation.
• U : B+ Line.
• H : adjustment for repair.
• Power voltages are dc 9 V and fed with regulated dc power
supply from external power voltage jack (J8) on the BASE
MAIN board, dc 12 V and fed with regulated dc power
supply from modular jack (J7) on the BASE MAIN board
with 100 Ω in series, and dc 3.6 V and fed with regulated
dc power supply from battery terminal on the HAND MAIN
board.
• Voltages and waveforms are dc with respect to ground in
test mode.
∗
: Impossible to measure
• Voltages are taken with a VOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
N : RX
O : TX
P : BELL
– 21 –
• IC Block Diagrams
U6 KA8602D (BASE MAIN Board)
RIPPLE
8
BIAS
REJECTION
CIRCUIT
7 MUTE
IN+ 1
IN– 2
– + – +
AMP1 AMP2
OUT1 3 6 OUT2
VCC 4 5 GND
U4 TA31103F (BASE MAIN Board)
U7 TA31103F (HAND MAIN Board)
24 23 22 21 20 19
∆G
–
+
EXP
SUM
MUTE
PRE AMP AMP
VREF
–
VREF
+
THROUGH
VREF
THROUG
COMP
MUTE
VREF
FILTER
FILTER IN 2
AMP 1
AMP 2 AMP
+ + +
– – –
∆G
1 2 3 4 5 7
6
U10 MC74HC595AF (BASE MAIN Board)
16 15 14 13 12 11 10 9
VCC
SHIFT REGISTER
LATCH
GND
2 3 4 5 6 7 8
1
PARALLEL DATA
OUTPUT
17 16 15 14 13
18
–
–
+
+
RO1 SWITCH
AMP RO2 CONTROL
AMP
VREF
VREF
SUM
AMP
MIC AMP
+
+
–
–
8 9 10 11 12
U11 LP2953IM (HAND MAIN Board)
GND 1 16 GND
2
NC
OUTPUT 3 15
ERROR
AMP
14
+
–
SENSE 4 13
SHUT DOWN 5
+
–
SHUT DOWN
COMPARATOR
DROP OUT
DETECTION AMP
+
ERROR 6
–
NC
7
GND 8 12
1.23V
AUXILLARY
COMPARATOR 11
10
9
– 22 –
INPUT
FEEDBACK
5V TAP
VREF
COMP IN
COMP OUT
GND