Kenwood NX-900 Service Manual page 89

Z
TX-RX UNIT (X57-8060-10) (A/2)
2
13
3.32V
13
450k
C710
0.01u
MIC
R850
MOD
1
/SCSW
13
450K
1
13
9
9
1
9
AA
SCHEMATIC DIAGRAM
BUFFER AMP
(2nd IF DET)
C707 R716
0.1u 0
R722
68k
C732
0.01u
VREF
1.67V
TC75W51FK(F)
5
R714
R705 100k
6
0 100k
7
8
MOD SMF
D704,705
AF DETECTOR
(LIMIT)
D704
2SC4738(GR)F
RB706F-40
R784
150k
D705
RB706F-40
R787
270k
2SA1832(GR)F
R779
470k
MIC SUM1
C764 R786 C773
22p 39k 0.1u
33A-2
1.67V
SUM AMP
(AI/TONE/MI1 MI2)
/(MOD/DI)
IC709
TC75W51FK(F)
MOD SUM
R773
680k
R774
470k
1.67V
AB
2
13
C729
0.1u
IC706
TC75W51FK(F)
MIC AA
1 8
VDD
7
R725
68k 2
R748
3 6
4 5
0
1.67V
VSS
LPF/SUM AMP MIC SUM2
1.67V
IC702
4 1.67V
VSS
3
R739
2
0
R731
1
VDD
0
LPF (MOD)
C720
0.1u
33A_2
Q704,705
LIMIT
Q704
Q705
MUTE (MI2)
MUTE (MI1)
R796 C782 C787
10k 0.1u 10u
3.29V
R : 3.3V
T : 0V
ME
R798 C784
1
680k 0.1u
R797 C783 R806
2
330k 0.1u 5.6k
R789
10
0
VREF
6
1
9
AC
NX-900
3.33V
R753 C742 R766 C748
56k 0.1u 100k 0.1u
VREF
C744
0.1u
IC708
TC7W53FK(F)
1 8
R767
CoMMoN VCC
47k
2 7
INH CH0
3
6 R768
VEE
CH1
4
GND 5 47k
A
AF SWITCH
(TXO/TXI)
SCSW(MIC)
C794
10u
Q707
2SJ243-A
3.29V
Q706
2SJ243-A
C795
10u
10
X57-806 (A/2) 6/14
AD
2
13
13
DTI
13
C762
0.1u
TXI
C763
TXO
0.1u
VREF
1
10
9
MI2
MI1
ME
89