McIntosh MA7000 Service Manual page 12

3 MAIN
750856 SCH 5 of 5
+15V
-15V
C105
R DRV FB
J26:5
9R
.0068uF
R140
+65V J26:7 47 .5 W
9R R B+
-65V J26:1 47 .5 W
9R
R B- R AMP
R139
R THERM
J26:3
9R R THERM
GND
J26:4 -18V
9R
TURN ON
R144
R 8 OHM 12.1k
J27:1
1
FB
J27:2
1
C101 C103
J27:3
1
R137 R141
R145 R147
R 2 OHM 221 6.49k .5%
J27:4
1
FB
R149
C108
+14R +14R +14R
R143
Q29
2
C102
C107
R146
R148
D26
R138 R142
Q31
R PG THERM 2
Q30
2
19
R151
R B+
+14R
100
R152
-14R
100
C110 C111 C112 C113
(+)
DIFFERENTIAL
AMP
C109
R157
R158
10uF
1.82k
3
Q34
475
R154
R153 D D
10M
Q32 Q33
3 3
G G
C115
S S
Q36
3
(+)
R164
CURRENT
SOURCE
R B-
R B+
(-)
R165 CURRENT
SOURCE
6
-
LD2
Q37
4
2 7 3
1
3
5
+
U19B
R150
-14R
R166
POWER GUARD
3 Q35
(-)
267k
+14R
R155
DIFFERENTIAL
U19A 47.5k
2 AMP
-
R156
R160
475
B+
1
B-
47.5k
3
+
R161
-14R
C114
R B-
R B+ R B+
2
Q42
(+)
VOLTAGE
AMP
Q45
Q40
3
R168
METER LOG AMP
C116
2
Q38
D27
D28
R170
R175
150k
R B-
+10V
R174 C118
22.1k
6
-
10uF
B+
U18B
B-
5
+
-5V
R B+
R171
Q39
2
C117
Q41
3
3 Q44
(-)
VOLTAGE
AMP
Q43
2
R173
R B- R B-
METER DRIVER
+10V
R176
7 2
-
D29 20K
B+ 1
U18A
B-
D31
3
+
-5V
R178
D30
C120
C119
-5V
R177
221k
20
RDRV [+]
J26:6
9R
RDRV [-]
J26:2
9R
+10V +10V
2
Q47
Q46
2 2
Q48
D32
R179
R MET [+]
J9:17
4
R MET FB
J9:19
4
R MET [-]
J9:20
4
R MET [-]
J9:18
4