McIntosh MC-2000 Service manual

POWER AMPLIFIER
CONTENTS
Performance Specifications ........................................ 2
Notes ......................................................................... 2
Rear Panel .................................................................. 3
Section Location ........................................................ 4
Block Diagram ...................................................... 5 - 6
Interconnection Diagram ...................................... 7 - 8
Main PCB and Schematic.................................. 11 - 13
Power Supply PCB and Schematic ........................... 14
AC Power PCB and Schematic .......................... 15 - 16
SERVICE MANUAL
Switch Remote PCB and Schematic .................. 17 - 18
Meter PCB and Schematic................................. 19 - 20
Bias Control PCB and Schematic ...................... 21 - 22
Meter Lamp PCB and Schematic ....................... 21 - 22
Lamp PCB and Schematic ................................. 21 - 22
Logo Lamp PCB and Schematic ........................ 21 - 22
Output PCB and Schematic............................... 21 - 22
Parts List ............................................................ 23 - 24
Exploded View and Parts List ............................. 25 - 28
Repacking Instructions ............................................. 29
PERFORMANCE SPECIFICATIONS
Power Output
130 watts into 8, 4 or 2 ohm loads is the minimum sine wave continuous average power output per channel from 20Hz to 20,000Hz with both channels operating.
Total Harmonic Distortion
0.5% maximum harmonic distortion at any power level from 250 milliwatts to rated power per channel from 20Hz to 20,000Hz with both channels operating.
Intermodulation Distortion
0.5% maximum intermodulation distortion if instanta­neous peak power output does not exceed twice the output rating per channel with both channels operating, for any combination of frequencies from 20Hz to 20,000Hz.
Rated Power Band
20Hz to 20,000Hz
Frequency Response (at 1 watt)
+0, -0.25dB from 20Hz to 20,000Hz +0, -3dB from 10Hz to 100,000Hz
Hum and Noise (A-Weighted)
100dB below rated output
Damping Factor
Greater than 18
Output Load Impedance
2, 4 or 8 ohms
Input Sensitivity (Switch Selectable)
2.5 volts for rated output
1.2 volts for rated output (1 volt for 100 watts output)
T ube Compliment
8 – KT88 or 6550 Output Tubes 4 – 12AX7A Input Tubes 2 – 12AT7 Driver Tubes
Power Requirement
100 Volts, 50/60Hz at 5.8 Amps 120 Volts, 50/60Hz at 4.8 Amps 230 Volts, 50/60Hz at 2.5 Amps
Note: Refer to the rear panel of the MC2000 for the correct voltage.
Dimensions
17-3/4 inches (45.1cm) wide by 11 inches (27.9cm) high. Depth behind front panel is 18-3/4 inches (47.6 cm). Handle clearance required in front of the mounting panel is 1-5/8 inches (4.1 cm).
Finish
Stainless Steel Chassis with Titanium Gold Super Mirror Finish, Black Transformer Enclosures, Black Base, Glass Front Panel with gold plated Handles and Knobs
Weight
Amplifier - 135 pounds (61.2 kg) net, 144 pounds (65.3 kg) in shipping carton Accessories - 18 pounds (8.2 kg) in shipping carton
Input Impedance
20k ohms Unbalanced (RCA Phono Jacks) 40k ohms Balanced (XLR Connectors)
1. The heavy lines on the schematics denote the primary signal path.
2. Unless otherwise noted, all voltages indicated on the schematics are measured under the following conditions: a. AC input at 120 volts, 50/60Hz b. All voltages are +/-10% with respect to ground. A high impedance (10megaohm) voltmeter must be used.
3. Unless otherwise specified: a. Resistors values are in ohms. b. Capacitor values are in microfarads (uF). c. Inductor values are in microhenries (uH).
NOTES
4. On PC Board Drawings, Square Pad Indicates: a. Polarized Capacitors - Positive b. Diode - Cathode c. Others - Pin 1
5. WARNING: Parts marked with the symbol have critical characteristics. Use only replacement parts recom mended by the manufacturer .
2
REAR PANEL
MC2000
3
SECTION LOCATION
TOP VIEW WITH COVER REMOVED
BOTTOM VIEW WITH COVER REMOVED
4
BLOCK DIAGRAM
VOLTAGE
N.F.B.
MC2000
LEFT
INPUTS
UNBALANCED
BALANCED
+
-
UNITY
GAIN
AMP
UNITY
INVERTING
AMP
BALANCED/
UNBALANCED
RELAY
BALANCED/
UNBALANCED
MODE SWITCH
1.2V/2.5V
LEVEL
RELAY
INPUT
LEVEL
SWITCH
MUTE
INPUT
AMP
PHASE
INVERTER
METER
HOLD
SWITCH
BUFFER
BUFFER
DRIVER
AMP
DRIVER
AMP
LOG
AMP
LOG
AMP
BUFFER
BIAS
CONTROL
BUFFER
RECTIFIER
HOLD
CIRCUIT
HOLD
CIRCUIT
RECTIFIER
OUTPUT
AMP
OUTPUT
AMP
DC
AMP
DC
AMP
DC
AMP
OUTPUT
TRANS-
FORMER
L. METER
8
4
2
COM
9
9
LEFT
OUTPUT
9
RIGHT
INPUTS
BALANCED
UNBALANCED
-
+
UNITY
INVERTING
AMP
UNITY
GAIN
AMP
BALANCED/
UNBALANCED
RELAY
1.2V/2.5V
LEVEL
RELAY
PHASE
INVERTER
MUTE BUFFER
INPUT
AMP
BUFFER
VOLTAGE
N.F.B.
DRIVER
AMP
DRIVER
AMP
BUFFER
BIAS
CONTROL
BUFFER
R. METER
DC
AMP
OUTPUT
AMP
OUTPUT
TRANS-
FORMER
OUTPUT
AMP
POWER SUPPLY SECTION
100/120/230VAC
50/60Hz
8
4
2
COM
POWER
RELAY
FUSE
9
9
RIGHT
OUTPUT
9
12VAC
LEFT
POWER
SUPPLY
RIGHT
POWER
SUPPLY
FUSE
FUSE
STANDBY
TRANSFORMER
INRUSH
CURRENT
LIMITER
INRUSH
CURRENT
LIMITER
CONTROL
5V SUPPLY
INPUT
VOLTAGE
SELECTOR
INPUT
VOLTAGE
SELECTOR
POWER
SWITCH
POWER
TRANSFORMER
POWER
TRANSFORMER
POWER
CONTROL
-+
12V
DC
12VAC
-+
12V
DC
IN
OUT
REMOTE
JACKS
12V
DC
12V
DC
MAIN 500V
DC SUPPLY
MAIN 500V
DC SUPPLY
-
150 AND
-
300V DC
-
150 AND
-
300V DC
REMOTE
LAMP
5
6
INTERCONNECT
7
8
MC2000
2R
2L
INPUT
049305
9
100
3R 3L
MAIN
049306
11
12
MC2000
3R
3L
MAIN
049306
4R
4L
POWER SUPPLY
049308
13
14
5
AC POWER 049309
15
16
MC2000
6
SWITCH REMOTE 049310
17
18
7R 7L
METER
049307
19
20
MC2000
8R 8L
10
LAMP
BIAS CONTROL
049311
049311
11R 11L
9R 9L
LOGO LAMP
METER LAMP
049311
049337
12R 12L
OUTPUT
049312
21
22
PARTS LIST
PART NO. DESCRIPTION REF. NO.
049305 Input
066316 CAP ELECT 10UF 20% 25V NP C1 C3 070047 SILICON DIODE 1N4148 T&R D1 D2 087056 REED RELAY FORM 1C 5V 125OHM K1 K2 117216 MALE CONN 5 PIN 0.1 POST ASSY J2­117221 MALE CONN 3 POS RT ANGLE J3­117722 9 POSITION RECEPTACLE J1­132222 N. CHANNEL FET Q6 144015 MF RES 33.2K 1% 1/4W R1 144104 METAL FILM RES 20K 1% 1/4W R6 144141 MF RES 27.4K 1% 1/4W R4 144154 RES MF 12.1K 1% 1/4W R23 144269 METAL FILM RES 1M 1/4W R11 R12 144379 RES METAL FILM 4.75M 1/4W 1% R19 144412 MF RES 15K 1% 1/4W R24 144421 MF RES 221K 1% 1/4W R2 144423 MF RES 174 OHM 1% 1/2W R8 R20 144439 MF RES 24.9K 1% 1/4W R5 R7
049306 Main
061293 DISC 22PF 500V C1 C17 061295 DISC 3.3 PF 1000V C2 061306 DISC 220 PF 100V C18 064364 CAP POLYPROP .047MF 10% 250V C25 064431 POLYPRO 0.1MF 630V C9 C10 064432 POLYPRO 0.22MF 1000V 20% C12 C13 064433 POLYPRO 1.0MF 250V 20% C4 064435 POLYPRO 2.2 MF 250V 10% C5 066492 ELECT 10MF 100V C8 C11 066493 ELECT 10MF 250V C15 C16 066494 ELECT 10MF 450V C19 066495 ELECT 47MF 16V C22 C24 066497 ELECT 47MF 450V C20 066498 ELECT 100MF 6.3V C6 C7 066500 ELECT 1000MF 16V NONPOLAR C14 066502 ELECT 4700MF 25V C21 C23 070126 DIODE 200V 3A D1 D2 089088 FUSE 2A SLO-BLO 5 X 20 250VIEC F 1 117217 MALE CONN 7 PIN J3­117218 MALE CONN 6-POS FRICTION LK J2­117723 9 POSITION HEADER J1­117724 9 CIRCUIT POST HEADER NATURAL J4­117725 9 CIRCUIT POST HEADER RED J5­122001 CHOKE 2.2 MH L1 L2 L3 L4 132136 TRANSISTOR NPN T092 Q1 Q2 Q3 Q4
Q5 Q6 133155 IC REGULATOR -12V IC2 133156 IC REGULATOR 12V IC1 134492 TRIM POT 2K 10% R7 139009 WIRE RES 220 OHMS 10% 5W R42 R43 R44
R45 139218 2.7 OHM 2W 5% WW RESISTOR FP R52 R53 144104 METAL FILM RES 20K 1% 1/4W R22 144106 33.2K 1% 1/4W R18 R51 144113 RES MF 100K 1% 1/4W R2 144119 METAL FILM RES: 332K 1% 1/4W R27 144141 METAL FILM RES 27.4K 1% 1/4W R50 144196 METAL FILM RES 100 OHM 1% 1/4W R14 144269 METAL FILM RES 1M 1/4W R9 144309 1K OHM 1% 1/2W METAL FILM R38 R39 R40
R41 144408 MF RES 562 OHM 1% 1/4W R13
144410 MF RES 1.2K 1% 1/4W R5 R10 144414 MF RES 18.2K R6 R8 144417 MF RES 93.1K 1% 1/4W R1 144418 MF RES 121K 1% 1/4W R4 144421 MF RES 221K 1% 1/4W R17 R21 R25
R26 144422 MF RES 1.5M 1% 1/4W R23 R24 144424 MF RES 3.92K 1% 1/2W R47 144427 MF RES 22.1K 1% 1/2W R46 144428 MF RES 47.5K 1% 1/2W R16 R20 R34
R35 144429 MF RES 100K 1% 1/2W R3 R11 144430 MF RES 121K 1% 1/2W R15 144431 MF RES 150K 1% 1/2W R19 144432 MF RES 1M 1/2W R32 R33 144435 MO RES 30.1K 1% 1W R36 R37 144436 MO RES 46.4K 1% 1W R28 R29 R30
R31 R48 144437 MO RES 10K 5% 2W R49 144438 MO RES 100K 5% 2W R54 178169 OCTAL TUBE SOCKET CERAMIC V4 V5 V6 V7 178170 9 PIN TUBE SOCKET CERAMIC V1 V2 V3
049308 Power Supply
064431 POLYPRO 0.1MF 630V C10 064434 POLY CAP .047UF 10% 1KV (MKP4) C9 066495 ELECT 47MF 16V C5 066496 ELECT 47MF 250V C6 C7 C8 066503 ELECT 810MF 300V C1 C2 C3 C4 070099 ZENER DIODE 12V 400MW D3 070131 DIODE RECTIFIER D5 D6 070165 BRIDGE RECT 1000V 6A D4 070166 MR253L TRANS. SUPPRESSOR D2 080017 TO-220 HEATSINK Q1 089088 FUSE 2A SLO-BLO 5 X 20 250VIEC F 1 117724 9 CIRCUIT POST HEADER NATURAL J2­117725 9 CIRCUIT POST HEADER RED J1­132284 MTP2955V FET POWER TRANSISTOR Q1 144415 MO RES 475 1% 1W R5 144425 MF RES 10K 1% 1/2W R1 R3 R4 144426 MF RES 15K 1% 1/2W R2
049309 AC Power
066501 ELECT 3300MF 35V C1 070031 SIL DIODE 400 PIV @ 1.5A (RED) D2 087071 RELAY TV8 5V COIL K1 089111 FUSE 50MA 5X20MM F1 117215 4-PIN CONNECTOR J8­117216 MALE CONN 5-PIN 0.1 POST ASSY J9 117719 PCB MOUNT POWER CONNECTOR RED J10- J11- J12-
J13- J14- J15­117726 .187 FASTON TAB J1 J2 J3 J4 J5 J6
J7 133108 IC +5V REGULATOR IC1 144090 METAL FILM RES 1K 1% 1/4W R1 144282 THERMISTOR RT1 RT2RT3
RT4 159314 TRANSFORMER 115/230-8/16V 6VA T1 178172 FUSE HOLDER 5X20MM F1
049310 SW Remote
061248 DISC CAP .1MF 25V Y5T C2 064329 CAP M POLY .22UF 5% 63VDC C1 117214 MALE CONN 3-POS MTS100 NORMAL J3 117218 MALE CONN 6-POS FRICTION LK J4­117406 MIN. PHONO JACK R657 J1- J2-
132171 TRANSISTOR NPN Q1 133192 IC NAND SCHMIT 2-IN X 4 IC1 144082 METL FILM RES 68.1 OHM 1% 1/4W R5 R6 144090 METAL FILM RES 1K 1% 1/4W R1 144187 METAL FILM RES 22.1K 1% 1/4W R2 R3 144269 METAL FILM RES 1M 1/4W R4 148074 SLIDE SWITCH DPDT 3MM S1 S2
049307 Meter
061248 DISC CAP .1MF 25V Y5T C4 C9 C10 C11 061249 DISC CAP .47UF 50V MONOLITHIC C12 C13 064329 CAP M POLY .22UF 5% 63VDC C8 064337 POLY CAP 1MF 5% 50V C7 066491 ELECT 4.7MF 100V C1 066499 ELECT 220MF 25V C2 C3 066510 CAP ELEC 1 UF 50V C14 070047 SILICON DIODE 1N4148 T&R D1 D3 D4 D6
D7 D8 D9 D10
D13 070085 ZENER DIODE 6.2V 5% 500MW D12 070131 DIODE RECTIFIER D2 D11 089088 FUSE 2A SLO-BLO 5 X 20 250VIEC F 1 117221 MALE CONN 3 POS RT ANGLE J2­117223 MALE CONN 6 PIN RT ANGLE J1­117240 4 PIN RT. ANGLE J3­131021 TRIAC 8A 200V Q8 132223 TRANSISTOR NPN MPS4124 2K/REEL Q1 Q5 132224 TRANSISTOR PNP Q2 Q6 132226 TRANSISTOR P.CHANNEL JUNC.FET Q7 132254 TRANSISTOR NPN Q3 Q4 133155 IC REGULATOR -12V IC2 133156 IC REGULATOR 12V IC1 133260 DUAL OPERATIONAL AMPLIFIER IC3 IC4 134383 TRIM POT 100K OHM 20% R10 141060 RES CF 3.3K 5% 1/4W R23 141125 RES CF 2.7M 5% 1/4W R1 141136 RES CF10 5% 1/4W R26 141179 CARB FILM RES 680 OHMS 5% 1/2W R24 144053 RES MF 10K 1% 1/4W R7 R20 R22 144053 RES MF10K 1% 1/4W R7 R22 144087 MF 499 OHMS R17 144090 METAL FILM RES 1K 1% 1/4W R19 R25 144103 16.5K 1% 1/4W R18 144117 METAL FILM RES 200K 1% 1/4W R6 R12 144125 METAL FILM RES 150K 2% 1/4W R9 144187 METAL FILM RES 22.1K 1% 1/4W R21 144196 METAL FILM RES 100 OHM 1% 1/4W R11 R16 144264 METAL FILM RES 10M 1% 1/4W R8 144269 METAL FILM RES 1M 1/4W R2 144271 METAL FILM RES 2.74M OHM 1/4W R13 144411 MF RES 3.92K 1% 1/4W R15 144412 MF RES 15K 1% 1/4W R5 R14 144342 MF RES 13.7K 1% 1/4W R20
049311 Bias Control
117217 MALE CONN 7 PIN J1­134497 TRIM POT 100K 10% R1 R2 144106 33.2K 1% 1/4W R3 150059 TACT SWITCH S1 S2
049337 Lamp
146252 3 POSITION 2POLE ROTARY SWITCH S1
049312 Output
064431 POLYPRO 0.1MF 630V C1 117726 .187 FASTON TAB J1 J2 J3 J4 J5 139119 WIRE RES 4 OHMS 5% 5W R1
23
240
MC2000
EXPLODED VIEW
1 OF 2
25
26
EXPLODED VIEW
2 OF 2
PARTS LIST
Ref. No.
1 016403 FRONT GLASS 2 049334 GOLD KNOB 3 104164 FELT WASHER 4 018628 HANDLE FRONT 5 018625 PANEL SIDE LEFT 6 018624 PANEL SIDE RIGHT 7 100200 MS 10-32 X 1/2 PHIL TRUSS BLK 8 017790 PLEXIGLAS PANEL 9 092424 METER COLOR FILTER 10 005007 PANEL PLATE 11 101142 CAP SCREW 1/4 -20 X 1-1/4 12 101215 SEMS MS 8-32 X 1/4 PHIL PAN 13 004961 DUST COVER 14 005006 GUSSET RIGHT 15 005005 GUSSET LEFT 16 005039 TOP SUBPANEL BRACKET 17 102003 MACH NUT: 6-32 W/LOCK 18 101078 TS 8-32 X 5/16 PHIL PAN BLK 19 126588 SIGNATURE NAMEPLATE 20 049379 WINDOW TRIM 21 101054 TS 6-32 X 1/4 PH PAN TAPTITE BLK
Part No.
Description
22 124071 METER 23 005008 SWITCH BRACKET 24 049357 METER ROTARY SWITCH PCB 25 049338 PANEL/LED LIGHT PCB 26 104163 M7 INTERNAL TOOTH LOCKWASHER 27 110004 M7 X .75 HEX CONTROL NUT 28 004970 SUBPANEL 29 092401 BLUE FILTER PALE 30 092400 BLUE FILTER AZURE 31 017749 METER LIGHT BOX 32 049336 METER LIGHT BOX PCB 33 114072 PLASTIC RIVET 34 049307 METER PCB 35 100296 SEMS 4-40 X 5/16 PHIL PAN 36 094360 FOAM TAPE 1/2” X 1/2” 37 094017 FOAM TAPE 1/4” X 1/4” 38 049339 PANEL LIGHT PCB 39 005018 CHASSIS GOLD 40 165065 12AX7A TUBE 41 165067 12AT7 TUBE 42 165069 KT88 TUBE 43 017761 AIR PIPE 44 049305 INPUT SWITCH PCB 45 114139 PCB SUPPORT 46 017801 PLASTIC RIVET 47 100292 MS 6-32 X 3/8 PH FH BLK ZINC 48 102006 MACH NUT: 10-32 W/LOCK 49 049304 POWER TRANSFORMER 50 126582 POWER TRANSFORMER DECAL 51 049301 OUTPUT TRANSFORMER 52 126581 OUTPUT TRANSFORMER DECAL 53 052093 TUBE COVER 54 101214 SCREW, TUBE COVER 55 049306 MAIN AMP PCB 56 004967 FOOT CHANNEL RIGHT 57 004968 FOOT CHANNEL LEFT 58 018626 FOOT 59 004971 CHASSIS SUPPORT 60 024010 FOOT PAD 61 005071 INPUT SHIELD BRACKET 62 005032 CHASSIS BASE 63 049310 SWITCH REMOTE PCB 64 049308 POWER SUPPLY PCB 65 049309 AC POWER PCB 66 018622 HANDLE REAR 67 117742 RCA JACK RED 68 117743 RCA JACK WHITE 69 117487 AC LINE RECEPTACLE 70 178122 FUSE HOLDER W/HARDWARE 71 117741 BINDING POST BLACK 72 117740 BINDING POST RED 73 117744 XLR RECEPTACLE 74 100195 MS 4-40 X 3/8 PHIL OVAL GOLD 75 104165 LW INTERNAL TOOTH 76 102052 NUT GOLD 77 100110 1/4-20 X 5/8 PAN PH BLK ZINC 78 104162 LOCKWASHER INTERNAL TOOTH 79 102051 HEX NUT M9 X .75 GOLD PLATED 80 049312 OUTPUT TERMINAL PCB 81 005035 BIAS PLATE LEFT 82 005036 BIAS PLATE RIGHT 83 049311 BIAS PCB 84 101193 SEMS 4-40 X 1/4 PHIL PAN BLK ZINC 85 004974 BIAS COVER 86 100193 MS 4-40 X 1/4 FLAT PH BLK ZINC 87 004969 BOTTOM COVER 88 100159 MS 10-32 X 3/4 PH PAN BLK ZINC
27
280
REPACKING INSTRUCTIONS
29
POWER AMPLIFIER
SERVICE MANUAL
The continuous improvement of it’s products is the policy of McIntosh Laboratory Incorporated, who reserve the right to improve design without notice. Because of the constant upgrading of McIntosh products’ circuitry and components, the Company cannot insure, and does not warrant, the accuracy of the within schematic material, which is intended for information only.
McINTOSH LABORATORY, INC., 2 CHAMBERS STREET, BINGHAMTON, NEW YORK 13903 Printed in U.S.A. Part Number 040702
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