McIntosh MA7000 Service Manual page 20

7 PREAMP
750683 SCH
+5V
MONO
RELAY
R INP J1:5 R1
3
1.5k
R5B
GND J1:6 50k -15V2
K1
3
C1 R8
5
D1 4 5
+
1k
R2 .47uF
L INP J1:8
COM
3 U2B
1.5k
6
-
GND
J1:7
3
+15V2
+15V J1:4 R16 10k
3 +15V
C9
-15V J1:3 100pF
3 -15V
+5.6V J2:9
4 +5V
VOL [+] 10
J2:1
4 VOL (+)
R13
VOL [+] J2:2
5 VOL (+)
R5C
VOLUME
C4
VOL [-] J2:3
4 VOL (-) VOL (-)
VOL [-] 10
J2:4
5
R12
MONO J2:7
4
RLY
HDPH J2:11
4 HDPH RLY
RLY
R10
+15V +15V2
10
R11
-15V -15V2
10
R5A
50k -15V2
C2
R9
8 2 3
+
.47uF 1k
U2A
COM
2
-
+15V2
R17 10k
C10
100pF
+15V2
7
McIn tosh
MA7000 P1324
Preamp PCB Assy
PC BD 129836
Insertion Assy 702455
PCB Assy 750683
35
C13
7
100uF
R20
5
R19B
2.74k
2k
R23 R28
681 681
6
-
7
U3B
CCW CCW
100k 100k
R22B C16 C18 R27B C20 C22
6 5 6
8 + 8
10uF .047uF 1.5uF .01uF
BALANCE
30 150
C14
1
100uF
R21
2
R19A
2.74k
2k
R24 R29
681 681
+15V2
2
-15V2 -
B+ 1
CCW U3A CCW
100k B- 100k
R22A C17 C19 R27A C21 C23
2 3 2
4 + 4
10uF .047uF 1.5uF .01uF
-15V2
R33 R38
681 681
6 6 6
- - -
7 7
U4B U5B U6B
CCW CCW
100k 100k
R32B C24 C26 R37B C28 C30
5 6 5 6 5
+ 8 + 8 +
.47uF .0033uF .15uF .001uF
500 1500
R34 R39
681 681
+15V2 +15V2 +15V2
2 2 2
- - -
B+ 1 B+ 1 B+
U4A CCW U5A CCW U6A
B- 100k B- 100k B-
R32A C25 C27 R37A C29 C31
3 2 3 2 3
+ 4 + 4 +
.47uF .0033uF .15uF .001uF
-15V2 -15V2 -15V2
-15V2
C34 C38
5
+
.22uF .22uF C48 R57
7
U7B
47uF 47.5
6
-
+15V2
R51 2.74k
C44
7
CCW
100k
R59
R42B C32 470pF
6
8
1k
.033uF
C52
220pF
+15HP
6
-
R61
7
U8B
100
C49
5
+
10uF
-15HP RIGHT
HEADPHONE
AMP
R49
+15V +15HP
221
R60
R50 1k
-15V -15HP
221 C53
10k
220pF
+15HP
2
-
R62
1
U8A
100
C50
3
+
10uF
-15HP
LEFT
HEADPHONE
AMP
-15V2
C35 C39
3
+
.22uF .22uF C51 R58
1
U7A
47.5
47uF
2
-
+15V2
R52 2.74k
C45
1
CCW
100k
R42A C33
470pF
2
4
.033uF
+15V2 -15V2
36
J1:1 R PRE
3
J1:2 L PRE
3
+5V
C54
J3 :1 R HP
4 1
4
470uF 3 2
K2
J3 :3 R HP
4
GND
J3 :5
4
J3 :7 GND
D2
4
2 3
C55
L HP
1 4 J3:9
4
470uF K3
J3:11 L HP
4