McIntosh C220 User manual

C220
Performance Specifications ........................................ 2
Notes ......................................................................... 2
Rear Panel .................................................................. 3
Section Location ........................................................ 3
Block Diagram ...................................................... 5 - 6
Interconnection Diagram ...................................... 7 - 8
Main Schematic and PCB ................................... 9 - 18
Display Schematic and PCB .............................. 19 - 24
Balanced/Data Sch and PCB .............................. 25 - 30
Pushbutton Sch and PCB .................................. 31 - 32
Headphone Sch and PCB ................................. 33 - 34
Backup Power Supply PCB ................................ 35 - 36
Parts List ............................................................ 37 - 43
Repacking Instructions ............................................. 45
CONTENTS
SERIAL NO. ZT1001 And Above
C220
TUBE PREAMPLIFIER
SERVICE MANUAL

PERFORMANCE SPECIFICATIONS
2
Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz
Total Harmonic Distortion
0.08% from 20Hz to 20,000Hz
Main Output
2.5V for rated input
Maximum Voltage Output
8V RMS Unbalanced, 16V RMS Balanced
Sensitivity (for rated output)
High Level, 450mV unbalanced, 900mV balanced
Phono, 4.5mV
Signal To Noise Ratio (A-Weighted)
High Level, 90dB below rated output
Phono, 80dB below 10mV input
Input Impedance
High Level, 22K ohms
Phono, 47K ohms; 65pF
Maximum Input Signal
High Level, 5V Unbalanced, 10V Balanced
Phono, 50mV (@ 1,000Hz)
Output Impedance
250ohms
Voltage Gain
High Level to Tape Output: 0dB
High Level to Main Output: 15dB
Phono to Main Output: 55dB
Headphone Output Impedance
16 ohms to 250 ohms
Tube Compliment
Phono Circuitry: 2 - 12AX7A
High Level Circuitry: 2 - 12AX7A
Power Requirements
100 Volts, 50/60Hz at 75 watts
110 Volts, 50/60Hz at 75 watts
120 Volts, 50/60Hz at 75 watts
220 Volts, 50/60Hz at 75 watts
230 Volts, 50/60Hz at 75 watts
240 Volts, 50/60Hz at 75 watts
Standby power, less than 1 watt
Note: Refer to the rear panel of the C220 for the
correct voltage.
Overall Dimensions
Width is 17-1/2 inches (44.45cm)
Height is 6 inches (15.24cm) including feet
Depth is 18 inches (45.72cm) including the Front Panel,
Knobs and Cables
Weight
21.1 pounds (9.59 kg) net, 37.5 pounds (17.05 kg) in
shippingcarton
Shipping Carton Dimensions
Width is 26-1/2 inches (67.3cm)
Depth is 24-1/4 inches (62.2cm)
Height is 11-3/4 inches (29.9cm)
1. The heavy lines on the schematic denote the primary
signal path.
2. Unless otherwise noted, all voltages indicated on the
schematics are measured under the following conditions:
a. ACinputat120volts,50/60Hz.
b. All voltages are +/-10% with respect to ground. A
high impedance (10 megaohm) voltmeter must be used.
3. Unless otherwise specified:
a. Resistor values are in ohms.
b. Capacitorvaluesaremicrofarads(uF).
c. Inductor values are in microhenries (uH).
4. On PC board drawings, Square pad indicates:
a. PolarizedCapacitors-Positive
b. Diodes - Cathode
c. Others - Pin 1
5. WARNING
Parts marked with the symbol have critical
characteristics. Use only replacement parts recom-
mended by the manufacturer.
NOTES

C220
REAR PANEL
SECTION LOCATIONS
TOP VIEW WITH COVER REMOVED
3

NOTES
4

C220
BLOCK DIAGRAM
5 6

7 8
INTERCONNECT
1

C220
910
MAIN 750984 SCH 1 OF 4
2A
4A
4A
4A
4A
4A
4A
4A
4A
4A
4A
LV
VCR
DVD
CD
GND
LEFT+
RIGHT
0V
.6V
0V
SAT
CD
2
L
R
L
R
R
L
R
0V
0V
0V
0V
0V
0V
0V
0V
0V
0V
0V
5V
5V
5V
0V
5V
5V
5V
5V
0V
0V
0V
0V
0V
0V
0V
5V
0V
0V
0V
0V
5V
5V
0V
R
L
TO BAL/DATA(
INPUT)
4A
4A
4A
4A
4A
4A
4A
4A
NC
5V
GND
GND
GND
LEFT-
LEFT+
0V
0V
DVD
3
CD 2
R
L
R
L
R
L
L
0V
0V
0V
0V
0V
5V
5V
5V
5V
0V
5V
0V
0V
0V
0V
0V
0V
5V
0V
10uF
C79
10uF
C69
0V
J8:5
J8:6
J8:7
J8:8
J8:9
J8:10
J8:11
J8:16
J8:17
J8:18
5V
5V
0V
0V
0V
0V
0V
0V R
.9V
PHONO AMP
.9V
.6V
120V
121V
120V
LEFT
PHONO AMP
INPUTS
TAPE
100pF
C82
DRIVER
DRIVER
0V
LEFT
DECODER
INPUT
.1uF
C50
221
R102
1k
R74
OUTPUTS
J8:2
J8:1
J8:4
J8:3
J8:15
J8:14
J8:13
J8:12
5V
5V
5V
0V
0V
0V
0V
0V
0V
INPUTS
PH
L
0V 1k
R88
0V 1k
R73
953
R93
110V
47pF
C58
47.5k
R91
953
R79
.1uF
C27
.1uF
C38
110V
47pF
C45
47.5k
R77
.001uF
C66
75k
R97
1M
R90
.001uF
C53
75k
R83
0V
.6V
1M
R76
21
3
Q22
12AX7A
59
4V5:3
3.32k
R123
22.1k
R168
22.1k
R94
3.32k
R51
121V
22.1k
R80
22.1k
R161
1uF
C60
1uF
C47
8
J3:8
VCR
6
J3:6
4
J3:4
3
J3:3
1
J3:1
5
J2:5
3
J2:3
4
J2:4
1
J2:1
TUNER
2
J2:2
220k
3 4
R115:2
10uF
C85
220k 1
2
R115:1
10uF
C81
220k12
R112:1
10uF
C75
10uF
C77
220k12
R107:1
10uF
C71
220k 1
2
R100:1
10uF
C63
220k
3 4
R89:2
10uF
C55
220k
3 4
R85:2
10uF
C52
10uF
C49
220k
34
R75:2
10uF
C43
2
1
3
4
K16
2
1
3
4
K14
2
1
3
4
K12
2
1
3
4
K4
2
1
3
4
K2
10uF
C146
10uF
C145
20K
R114
40.2k
R111
1k
R108
20K
R113
100pF
C76
INPUT
0V
RIGHT
.1uF
C72
22uF
C68
100k
R134
DECODER
DECODER
.1uF
C105
0V
100k
R130
0V
221
R110
1k
R173
1k
R72
1J6:1
2J6:2
GP1
100uF
C64
1.82k
R96
100uF
C51
1.82k
R82
1.5k
R78
1.5k
R92
200k
R87
.1uF
C56
200k
R71
.1uF
C42
12AX7A
59
4V7:3
2 1
3Q31
21
3Q27
5
J3:5
7
J3:7
2
J3:2
6
J2:6
10uF
C86
10uF
C83
220k
3 4
R112:2 220k
3 4
R100:2
220k
3 4
R107:2
10uF
C57
10uF
C65
220k 12
R85:1
220k 1
2
R89:1
220k 1
2
R75:1
2
1
3
4
K10
2
1
3
4
K8
2
1
3
4
K6
221k
R189
221k
R188
100pF
C74
20K
R106
40.2k
R109
100pF
C84
20K
R105
2
1
3
5 4
K17
2
1
3
5 4
K18
1k
R172
CONTROL
CONTROL
J5:11
RIGHT- J5:10
RIGHT- J5:9
RIGHT+ J5:8
RIGHT+
J5:2
J5:1
365
R201
PHONO
ON/OFF DRIVER
100pF
C80
BALANCED TO UNBALANCED
CONVERTER
BALANCED TO UNBALANCED
TAPE
J5:18
J5:17
CONTROL
CONTROL
J5:13
J5:16
J5:15
J5:14
LEFT-
J5:6
J5:7
J5:4
J5:5
2
J16:2
1
J16:1
1M
R98
.0033uF
C67
12AX7A
3
2
1
V7:1
12AX7A
86
7
V7:2
1uF
C59
1M
R84
.0033uF
C54
12AX7A
86
7
V5:2
12AX7A
3
2
1
V5:1
100uF
C48
1uF
C46
2
1
3
4
K15
2
1
3
4
K13
2
1
3
4
K11
2
1
3
4
K3
2
1
3
4
K1
40.2k
R104
40.2k
R101
1k
R99
22uF
C78
.1uF
C73
CONVERTER
100pF
C70
2
3
1
-
+
8 4
B+
B-
U10:1
220k
3 4
R103:2
10uF
C16
220pF
C44
J5:12
J5:3
100uF
C62
221k
R95
221k
R86
221k
R70
221k
R81
2
1
3
4
K9
2
1
3
4
K7
2
1
3
4
K5
6
5
7
-
+
U10:2
QF
5
QG
6
QD
3
QA
15
QB
1
GND 8 QH
7
SQH 9
OE 13
VCC
16
QC
2
QE
4
LCLK 12
RESET 10
SCLK 11
DATA 14
U13
QF
5
QG
6
QD
3
QA
15
QB
1
GND 8 QH
7
SQH 9
OE 13
VCC
16
QC
2
QE
4
LCLK 12
RESET 10
SCLK 11
DATA 14
U8
6
7
8
9
1
2
3
4
514
15
16
17
18
10
11
12
13
GND
U9
QF
5
QG
6
QD
3
QA
15
QB
1
GND 8 QH
7
SQH 9
OE 13
VCC
16
QC
2
QE
4
LCLK 12
RESET 10
SCLK 11
DATA 14
U6
6
7
8
9
1
2
3
4
514
15
16
17
18
10
11
12
13
GND
U7
220k 12
R103:1
595CS
ACC_ON
CD_CONTROL
CD_CONTROL
CD_CONTROL
CD2_CONTROL
CD2_CONTROL
DVD_CONTROL
DVD_CONTROL
DVD_CONTROL
LEFT-
LEFT-
LEFT+
LEFT+
MONO
MUTE
PC_SPKR1
PC_SPKR2
PH_CONTROL
PH_CONTROL
PH_POWER
PH_POWER
POWERON
PWR_ONATTN
RIGHT-
RIGHT-
RIGHT+
RIGHT+
SAT_CONTROL
SAT_CONTROL
SAT_CONTROL
SCLK
SCLK
SCLK
SDATA
SPKR1
SPKR2
SQH1
TAPE_CONTROL
TAPE_CONTROL
TAPE_CONTROL
TONE_BYPASS
TU_CONTROL
TU_CONTROL
TUBE_LIGHT
VCR_CONTROL
VCR_CONTROL
VCR_CONTROL
175V
175V
236V
236V
236V
236V 5V
24V
24V
24V
5V
5V
5V
5V
5V
5V
5V
5V
5V
5V 5V
5V 5V
5V5V
5V 5V
5V
5V
5V
5V
5V
15V -15V
5V 5V
5V
5V
5V
5V
5V
15V
-15V
LISAUD-L LISAUD-R
HDPH MUTE
HDPH MUTE
HDPH MUTE 2
1
3
4
K20
2
1
3
4
K19
5V
5V
22.1k
R184
22.1k
R185

11 12
MAIN 750984 SCH 2 OF 4
2B
0V
GND
3C J5-3
GND
3C J5-4
0V
3C J5-5
5V
3C J5-6 3C J5-8
15V
3C J5-9
3C 3C
3C 3C 3C 3C
GND
0V
0V
1V
1V
114V
RIG HT 0V
.6V .6 V
.6V
0V
.6V
0V
0V
.6V .6 V
0V
0V
0V
L T O N E 1
0V
L TONE 2
0V
0V
5V 5V
BYPASS
0V
15V J5-10
-15V
-15V J5-11
GND
-15V
J5-13
GND
0V J5-14
0V J5-15
R T O N E 2
0V J5-16
0V 0V
AMP
200k
R48 200k
R4
0V
0V
0V
.6V
0V
0V
0V
.6V .6 V
1M
R49
0V
0V
J1:15
J1:14
J1:10
J1:9
J1:5
J1:4
16.5k
R10
-15V -5V
5 VO L T REG U L A TO R
POSITIVE
0V
0V
RIG HT
VOLUME CONTRO L
220pF
C31
0V
VOLUME CONTRO L
BUFFE R
5V
1k
R43
5V
3C J5-1
GND
5V
3C J5-2
0V
-5V
15V
3C J5-7
3C
0V
0V
3C
3C
1V
1V
115V
10k
R116
130V
113V
AMP
.6V
-13.7V
220pF
C149
LEFT
5V
5V
5V
5V
5V
DECODER
DRIVER
-3dB DRIVER
-3dB DRIVER
0V
-6dB DRIVER
-6dB DRIVER
-3dB
.6V
-6dB
0V
-9dB
.6V
-12dB DRIVER
-12dB 0V
NEGA TIV E
3
1
2IN OUT
U2
5V15V
5 VO L T R EG U L A T O R
2
31 IN OUT
U1
267k
R20
2
1
3
4
K27
10k
R34
267k
R36
.1uF
C19
.1uF
C20
221
R127
10uF
C26
BUFFER
0V
LEFT
47.5k
R220
0V
5V
267k
R200
VOLUME CONTRO L
47uF
C17
0V
5V
0V
.1uF
C150
0V
-15V
0V
15V
TO DISPLAY
DS4
DS2
1k
R171
1k
R169
10uF
C151
.1uF
C155
.1uF
C25
R T O N E 1
GND
0V
J5-12
RIG HT TONE
J5-17
J5-18
1M
R56
3.32k
R58
221k
R47
.1uF
C36
1M
R12
3.32k
R18
221k
R3
.1uF
C2
47pF
C11
15K
R69
1.5k
R57
22.1k
R64
47pF
C10
1.5k
R17
22.1k
R21
22.1k
R158
135V
1uF
C39
12AX7A
59
4
V3:3
12AX7A
59
4
V1:3
31
2
Q26
1uF
C6
TUB E MUTE
150k
R55
20K
R1
150k
R2
10M
R175
1M
R128
-13.7V
TUB E MUTE
5V
5V
5V
POST ATTENUATO R
TUBE MUTE
3 1
2
Q29 200k
R129
31
2
Q10
.6V
3
1
2
Q5
1M
R25
267k
R24
-3dB
10uF
C37
47.5k
R59
31
2
Q9
1M
R46
.6V .6 V
31
2
Q6
267k
R26
0V
1 2
3
S
G
D
Q1
10uF
C1
-6dB
33.2k
R60
1000pF
C32
1M
R45
1000pF
C13
267k
R28
10M
R14
1 2
3
S
G
D
Q2
-9dB
24.9k
R62
1000pF
C34
.6V
1000pF
C14
1M
R29
267k
R30
0V
10M
R15
-12dB
1000pF
C35
.6V
1000pF
C15
1M
R31
10M
R16
0V
10k
R19 10uF
C8
10uF
C156
.1uF
C152
1k
R42
10uF
C153
J1:18
267k
R32
J1:17 J1:16
J1:12
J1:11
47uF
C148
31
2
Q32
DS3 DS1
47uF
C147
J1:6 J1:7 J1:2
J1:1
12AX7A
86
7
V3:2
22.1k
R151
12AX7A
86
7
V1:2
15K
R23
10k
R118
20K
R53
10M
R174
267k
R38
267k
R39
1 2
3
S
G
D
Q13
47.5k
R7
10M
R66
267k
R40
1 2
3
S
G
D
Q14
33.2k
R8
10M
R67
267k
R41
24.9k
R9
10M
R68
8.25k
R125
100V
2.74k
R5
100V
47pF
C4
114V
1k
R44
.47uF
C18
-9dB DRIVER
-9dB DRIVER -12dB DRIVER
LEFT POST ATTENUATOR
47uF
C22
12.1k
R22
6
5
7
-
+
U3:2
12.1k
R37
47uF
C41
10k
R170
10uF
C154
1 2
3
S
G
D
Q30
1uF
C92
1uF
C40
2 1
3Q25
1k
R54
22uF
C5
47pF
C3
1uF
C7
1uF
C24
1000pF
C33
.1uF
C28
1000pF
C12
1M
R27
-13.7V
10M
R13
2.21M
R61
16.5k
R63
31
2
Q12
31
2
Q11
1M
R50
31
2
Q8
31
2
Q7
1 2
3
S
G
D
Q4
1 2
3
S
G
D
Q3
2
3
1
-
+
84
B+
B-
U3:1
12AX7A
3
2
1
V3:1
2.74k
R52
12AX7A
3
2
1
V1:1
47uF
C9
J1:8
J1:3
J1:13
1 2
3
S
G
D
Q28
2 1
3Q24
10M
R65
1 2
3
S
G
D
Q15
1 2
3
S
G
D
Q16
2.21M
R6
QF 5
QG 6
QD 3
QA 15
QB 1
GND
8QH 7
SQH
9
OE
13
VCC 16
QC 2
QE 4
LCLK
12
RESET
10 SCLK
11 DATA
14
U4
RIG HT POS T ATTENUATO R
9
10
11
12
13
14
15
161
2
3
4
5
6
7
8
ZCEN
DATAO
DATAI
AINR
AGNDR
AOUTR
VA+
VA-
AOUTL
AGNDL
AINL
M\U\T\E\
SCLK
VD+
C\S\
DGND
U5
L_OUT
L_TONE_1 L_TONE_2
MONO
PWR_ONATTN
R_OUT
R_TONE_1 R_TONE_2
TONE_BYPASS
TUBE_LIGHT
TUBE_ON
VOL_CLK
VOL_CLK
VOL_CS
VOL_CS
VOL_DATA
5V2 -5V2
5V2
-5V2
15V
-15V
5V
5V2
5V2
5V2
-5V2
15V 15V
170V
236V
236V
170V
236V
236V
5V
5V
-15V -15V -15V -15V
-15V
-15V
-15V -15V -15V -15V -15V -15V -15V -15V
-15V -15V
-15V
5V
5V
24V
24V
5V2
-5V2
-24V 5V
LISAUD-L
LISAUD-R
L_TONE_1 L_TONE_2
R_TONE_1 R_TONE_2
15V -15V
TUBE_POWER

C220
13 14
MAIN 750984 SCH 3 OF 4
2C
0V
0V
0V
0V
0V
0V
0V
0V
5V
5V
5V
5V
0V
0V
0V
0V
0V
1
1
5V
6
6
6
6
6
6
6
4B
4B
4B
4B
4B
4B
4B
J2:2
J2:3
J2:4
J2:8
J2:4
J2:3
J2:2
J7:9
J7:7
0V
0V
0V
0V
0V
0V
0V
LEFT
5V
5V
0V
0V
0V
0V
0V
0V
0V
2
5V
2
6
6
6
6
6
4B
4B
4B
4B
4B
J2:1
J2:5
J2:6
J2:7
J2:1
J7:8
TO HEADPHONE TO BAL/DATA PCB (OUTPUTS)
0V
RIGHT
.1uF
C121
.1uF
C122
LEFT
R
R
R
L
L
SPKR1
OUTPUTS
SPKR1
SPKR2
MAIN
1k
R152
BUFFER
0V
INVERTING
BUFFER
0V
0V
RIGHT
0V
BUFFER
0V
AGND
0V
0V
NC
NC
R HDPH
R HDPH
HDPH
GND
HDPH
GND
L HDPH
L HDPH
OUTPUT
OUTPUT
OUTPUT
MUTE
MUTE
GND
4B J7:4
4B J7:3
4B
LEFT +
J7:2
LEFT +
0V
BUFFER
OUTPUT
BUFFER
OUTPUT
33.2k
R193
10uF
C130
10uF
C116
33.2k
R192
2
1
3
4
K21
2
1
3
4
K24
2
1
3
4
K23
100k
R159
100k
R154
100k
R146
100k
R143
10uF
C132
7
J6:7
10uF
C127
3
J6:3
10uF
C123
4
J6:4
L
10uF
C118
8
J6:8
MAIN
SPKR2
10uF
C133
10uF
C136
.1uF
C126
10k
R157
10k
R139
1k
R137
INVERTING
RIGHT
10k
R155
0V
10k
R138
.1uF
C134
.1uF
C135
BUFFER
LEFT
47uF
C129
47uF
C115
100
R164
100
R166
NC
NC
GND
HDPH
GND
HDPH
OUTPUT
RIGHT -
RIGHT +
RIGHT -
4B
4B
RIGHT +
GND
J7:5
J7:6
4B
LEFT -
LEFT -
J7:1
2
1
3
4
K26
2
1
3
4
K25
2
1
3
4
K22
100k
R163100k
R150
10uF
C128
5
J6:5
10uF
C119
6
J6:6
2
3
1
-
+
84
B+
B-
U18:1
221
R145
HEADPHONE
HEADPHONE
J7:3
J7:2
J7:10
J7:11
J7:18
J41:1
J7:15
J7:14
J41:5
J7:13
J41:6
J7:10
J41:10
J16:3
J41:16
J41:17
6
5
7
-
+
U19:2
221
R162
221
R153
221
R148
221
R142
10k
R167
6
5
7
-
+
U21:2
.1uF
C125
J7:1
J7:4
J7:8
J7:5
J7:6
J7:7
J7:12
J7:16
J7:17
J41:2
J41:3
J7:11
J7:12
33.2k
R160
J41:8
J41:7
J41:11
33.2k
R144
J41:13
J41:14
J41:18
2
3
1
-
+
8 4
B+
B-
U19:1
221
R156
10k
R165
2
3
1
-
+
8 4
B+
B-
U21:1
6
5
7
-
+
U18:2
J7:9
J41:4
J41:9
J41:12
J41:15
L_MAIN
L_MAIN
L_OUT
LMAIN
MUTE
MUTE
R_MAIN
R_MAIN
R_OUT
RMAIN
SPKR1
SPKR2
L_MAIN
R_MAIN
RMAIN
LMAIN
5V
5V
5V
5V
5V
5V
5V
SPKR2 SPKR1 15V -15V
15V -15V
15V -15V
15V
-15V
15V
-15V
15V
-15V
HDPH MUTE
2
1
3
4
K28
2
1
3
4
K29
5V
5V
470uF
C101
470uF
C99
1k
R187 1k
R186

15 16
MAIN 750984 SCH 4 OF 4
2D
7
7
AC
AC
N
POWER
SEC 4
SEC 1
T1
T1
T1
T1
GRN
GRN
BLU
RED
D11
312V
DRIVER
DATA
15V
GND
GND
5V
DATA
ACC
SCLK
NC
VOLCK
SDATA
SCLK
FIL2
GND
GND
4
4
4
4
4
4
4
4
4
4
3A
3A
3A
3A
3A
3A
3A
3A
3A
3A
J16:9
J16:8
J16:5
J16:4
J16:3
L
230/240 VAC
100 VAC
T1
T1
T1
T1
T1
BRN
BRN
BLU
D15
D12
.6V
5V
237V
200k
R141
5V
0V
5V
5V
VOLCS
595CS
5V
FIL1
GND
4
4
4
4
4
4
4
4
3A
3A
3A
3A
3A
3A
3A
3A
J16:6
J16:7
J16:1
J16:2
TO DISPLAY
220 VAC
D13 1.5k
R35
TO BAL/DATA PCB (DATA)
120V B
20V B
NC
NC
100V A
NC
0V A
120V B
NC
20V B
NC
0V B
NC
0V A
NC
120V B
T1
T1
120V A
T1
100V A
0V A
120V B
NC
20V B
NC
0V B
NC
0V A
NC
15
14
6
4
3
12
9
8
7
FIL1
FIL2
J9:8
RED
YEL
J9:1
REGULATOR
D5
D3
312V
33V
-33V
33V
-33V
NEGATIVE 24 VOLT
237V
.1uF
C98
15V
REGULATOR
REGULATOR
24V
POSITIVE 24 VOLT
15.6V
238V
5V
5V
EXTERNAL
PASSTHRU
EXT. DATA BUFFER
0V
5V
IR MUTE
0V
0V
5V
5V POWERON
5V
5V
0V PC SPKR1
VOL DATA
EX DATA
IR TO
DATA PORTS
VFD -30V
J16:18
J16:15
J16:14
J16:13
J16:10
J1:18
J1:15
J1:14
J1:13
J1:10
J1:9
J1:8
J1:5
J1:4
J1:3
0V B
120V A
NC
NC
NC
NC
100V A
120V A
T1
NC
20V B
0V B
120VAC
T1
T1
120V A
NC
NC
100V A
10
11
13
5
2
PRIMARY
TRANSFORMER
T1
5.2 VAC
J9:4
J9:5
J9:9
J9:6
J9:7
J9:3
J9:2
T500mAL 250V
F5
T125mAL 250V
F4
D9
.047uF
C100
D7
D8
9.7V
POSITIVE 5 VOLT
.047uF
C89
D1
D2
3.32k
R131
238V
47uF
C23
47uF
C21
5V
1.82k
R178
2200uF
C962200uF
C93
3.32k
R120
REGULATOR
3.32k
R181
5V
.1uF
C104
2 3
1
Q17
POSITIVE 15 VOLT
332
R124
NEGATIVE 15 VOLT
-15V
.1uF
C94
332
R176
REGULATOR
.1uF
C91
365
R119
-24V
.1uF
C87
365
R183
33.2k
R140
20K
R149
200k
R122
236V
267k
R135
10
R117
100k
R196
10uF
C29
100k
R197
5V
1
2
3
147
B+
GND
U17:1
SENSOR 5-8V
BUFFER
TUBE WARMUP
1k
R132
CONTROL
4.3v
5V
IR MUTE
CONTROL
5V
0V
POWERON
PC SPKR2
595CS
SQH1
5V
IR MUTE
CONTROL
TUBE ON0V
J16:16
J16:17
J16:11
J16:12
J1:17
J1:16
J1:12
J1:11
J1:7
J1:6
J1:2
J1:1
T2AL 250V
F2
D6
4700uF
C30
.1uF
C103
1.82k
R180
1.82k
R179
1.82k
R1773.32k
R182
3.32k
R136
1M
R147
3
21
Q20
3 1
2
Q18
10uF
C61
1k
R133
J15:4
J15:5
J14:1
J14:6
J13:3
J13:4
J12:1
J12:6
SEC 2
RELAY DRIVER
J4:5
J4:10
J4:15
J8:5
J8:10
-24V
-24V J8:15
J15:3
J15:2
J15:1
J14:2
J14:3
J15:6
J13:1
J14:4
J14:5
J13:5
J13:6
J12:4
J12:2
J12:3
J11
GP2
.047uF
C106
2
31 IN OUT
U16
SEC 3
12
13
11
U17:4
100k
R11
22.1
R121
10uF
C97
3 2
1
IN OUT
U15
10uF
C95
3
1
2IN OUT
U14
220uF
C90
3 2
1
IN OUT
U12
220uF
C88
3
1
2IN OUT
U11
D10
9
10
8
U17:3
4
5
6
U17:2
J4:3
J4:2
J4:1
J4:8
J4:7
J4:6
J4:12
J4:13
J4:11
J4:18
J4:16
J4:17
J8:2
J8:1
J8:7
J8:6
J8:4
J8:3
J8:12
J8:11
J8:9
J8:8
-24V
J8:16
J8:17
J8:14
J8:13
J8:18
J13:2
J10 J12:5
2 3
1
Q21
1000uF
C102
100k
R126
J4:9
J4:4
J4:14
595CS
595CS
ACC_ON
FIL1
FIL1
FIL2
FIL2
IR_DATA
IR_DATA
PC_SPKR1
PC_SPKR2
POWERON
POWERON
SCLK
SCLK
SDATA
SQH1
TUBE_ON
VOL_CLK
VOL_CS
VOL_DATA
5V
5V
-24V
VF-24V
VF-24V
24V
-15V
15V
15V
5V
5V
5V
170V
236V
175V
5V
100k 2w
R33
15V
22.1k
R222
12.1k
R221 D17
100k
R223
5V
31
2
Q19
J34:1
J34:2
J34:3
J34:4
POWER
RLY
+VBU
GND
9.7V
9.7V
50/60Hz 75W50/60Hz 75W50/60Hz 7 5 W
50/60Hz 75W
0V
.6V
2 1
3
Q33
5V
365
R224
31
2
Q34
TUBE_POWER
D4
D14
15V 9.7V
15V2
47.5
R190
220uF
C107
15V2
J4
J7
TO
STANDBY
POWER SUPPLY
PCB
7
7
7
7
J1:1
J1:2
J1:3
J1:4
TO STANDBY
POWER SUPPLY

C220
17 18
MAIN 750984 PCB
2

19 20
DISPLAY 751002 SCH 1 of 3
3A

C220
21 22
DISPLAY 751002 SCH 2 of 3
3B

23 24
DISPLAY 751002 SCH 3 of 3 and PCB
3C

C220
25 26
BALANCED / DATA 750933 SCH 1 of 2
4A

27 28
BALANCED / DATA 750933 SCH 2 of 2
4B

C220
29 30
BALANCED / DATA 750933 PCB
4

31 32
PUSHBUTTON 751003 SCH and PCB
5

C220
33 34
HEADPHONE 750332 SCH and PCB
6

35 36
BACKUP POWER SUPPLY 750985 SCH and PCB
7
1
1
J2
J3
t
R1
D3
D4
D2
D5
AC N
AC LINE
1
1
1
1
1
D1
J5:3
J5:1
POWER
RLY
TO MAIN
2D
26
8
4
1
3
5
7
PRIMARY
T1
+VBU
GND
J5:4
1
J6:1
J6:2
[+] TP[-]
TESTONLY
NO CONNECTION
J7
J4
AC LINE FILTER
N
L
G!
!
!
!
!
FN1
J1:3
J1:2
J1:1
J1:4
J1:5
J1:6
! !
VOLTAGE SELECTION JUMPERS
240V
220V
120V
100V
100V
120V
230V
110V
110V
+VBU
D6
23
14
K1
AC N
AC
F1
J5:2
2D
2D
2D
2D
J34:3
J34:4
J34:2
J34:1
J10
2D J11