Ncu Pcb; Color - Brother FAX1170 Service Manual

3.3

NCU PCB

The NCU PCB switches the communications line to telephone or built-in MODEM, under the
control of the main PCB.
1
1
A
2
R A 3 5 1 X 2
A 3
4
S B T 0 2 6 0 X 2
5
o r
F L 5 R 2 0 0 P N X 2
F G F G
J W 1 6
8
4
B
3
7
A
A
4 - 4 P M J
2
C
3 S 0 V
S B T 0 2 6 0 X 4
S R E F
o r
F L 5 R 2 0 0 P N X 4
4
1
A
D
3 . C O M P O N E N T S I N P A R E N T H E S I S N O T T O B E
1
1 Surge absorbers
2 Line relay (CML relay)
3 Line transformer
4 Circuit related to the line transformer
5 High-impedance transformer circuit
6 Calling signal detector
7 Loop current detector
8 Dial pulse generator
9 Telephone circuit
: Reference voltage generation circuit for the operational amplifiers in 4 and 9
A Noise filters (provided on the FAX1570MC/MFC1870MC/1970MC)
2 3
+ 2 6 V
2
C R 1
M Z F - 2 4 H G
C M L
o r
O U A Z - S S - 1 2 4 D
+
-
P L S
1
4
3 2
S 0 V
V 1
R 2 4
2 1
J W
6
T E L O F F
3 4
S 0 V
+ 5 V
C
T E L R L
B
E
S 0 V
M O U N T E D .
2 3
NCU PCB Circuit Diagram (U.S.A. versions)
4
3
4
S 0 V
5
R L 2
4
5
5
R E F
1 4 R E F
C I
S 0 V
2 3
5 3 1
6 4 2
9
+ 2 6 V
+ 5 V
J W 9
S R E F
T E L S L
S 0 V
S 0 V
4
III – 27
5
4
S 0 V
R E F
F G S 0 V
4 2
+ 5 V
+ 2 6 V
3 1
8
+ 5 V
o r
B A 1 0 3 5 8
S 0 V
4
:
S 0 V
R E F
5
6
N C U S L
A
R L 1
T E L S L
T E L R L
P L S
T E L O F F
C I
B
R L 2
C M L
+ 2 6 V
+ 5 V
S 0 V
C
P 1
6 0 3 3 B - 1 2 Z
D
6