McIntosh MC302 Service Manual page 20

7 HEATSINK
751293 SCH 2 OF 2
DRV +
D5
1.8V
2
Q23
0V
+ V AMP
J4:1
3
HS OUT
- V AMP
J4:2
3
0V
2
Q24
-1.8V
D6
DRV -
35
1.8V
POS
3
Q26
DRIVER
1.2V
POS
CURRENT
LIMITER
R51
680
0V
D7
R68
R53
1.8V
1V
2
Q25
.4V
R55
BIAS
2
ADJUST
R54
NEG
CURRENT
LIMITER
0V
680
R50
Q34:2
BIAS
D8 THERMAL Q33:2
TRACKING
Q35:2
-1.2V
NEG
3
Q27
DRIVER
-1.8V
1
Q40
.6V
1
Q28:1
.6V POS
1
Q30:1
OUTPUTS
.6V
1
Q32:1
.6V
R57 R59
.47 x 2 .47 x 2
3 1 3
R56
3 1 3
.47 x 2 .47 x 2
R58 R60
-.6V
1
Q33:1
-.6V
NEG
1
Q31:1
OUTPUTS
-.6V
1
Q29:1
-.6V
1
Q41
+V AMP
BIAS ADJUSTMENT
1
Q34:1
ADJUST R52
FOR 21-25 mVDC
ACROSS J5
.6V
WITH NO INPUT SIGNAL
1
Q36:1
AND HEATSINKS COOL
.6V
1
Q38:1
R61
.47 x 2
1 3 1
JMP1
1 3 1
.47 x 2
R62
1
1 3
Q39:1
-.6V
.47 x 2
R63
1
Q37:1
-.6V
1
Q35:1
-V AMP
36
R67
J5:1
BIAS [-]
1.5k
R66
J5:2
BIAS [+]
1.5k
R64
.47 x 2
3 1
HS OUT 1
J7
1
WHT
HS OUT 2
J6
1
VIO
1 3
.47 x 2
R65