McIntosh MC 402 Service Manual

Page 1

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CONTENTS
Performance Specifications ........................................ 2 Input Schematic and PCB .................................. 17 - 18
Notes ...... 2 Capacitor Schematic and PCB .
Rear Panel . 3 Meter .................................
Section Location . 4 Indicator Schematic and PCB
BIock Diagram ............... 6 Meter LED Schematic and PCB ..
Interconnection Diagram 8 Paris List .............................
Heatsink Schematic and PCB 2 EprodecI View and Parts List .

Driver Schematic and PCB 13 - 16

Repacking Instructions

SERVICE MANUAL

Page 2

PERFORMANCE SPECIFICATIONS

Power Output Stereo

Minimum sine wave continuous average power output per
channel, aLl channels operating is:

400 watts into 2 ohm load

400 watts into 4 ohm load

400 watts into 8 ohm load

Power Output Mono Parallel

Minimum sine wave continuous average power cumut is:
800 watts into 1 ohm load

800 watts into 2 ohm load

800 watts into 4 ohm load

OutputLoad Inpedanee
2, 4 or 8 ohms (Stereo Mode)
l, 2 or 4 ohms (Mono Mode)

Rated Power Band
20Hz to 20,0 OOHz

Total Harmonic Distortion
Maximum Total Harmonic Distortion at any power level
from 250 milliwatts to rated power output is 0.005n n

Intermodulafion Distortion

Maximum Intermodulation Distortion if instantaneous peak
output per channel does not exceed twice the rated output,
for any combination of frequencies fiom 20Hz to 20,000Hz,
with all channels operating is 0.005%

Dynamic Headroom
2. MB

Frequency Response
+0, ~0.25dB from 20Hz to 20,000Hz
+0, -3dB fiom 10Hz to 100,000Hz

Sensitivity
2.0 Volts Unbalanced Input
40 Volts Balanced Input

A-Weighted Signal To Noise Ratio
94dB Unhalanced(120dB below rated output)
98613 Balanced (124dB below rated output)

Input Impedance
10,000 ohms Unbalanced Inputs
20,000 ohms Balanced Inputs

Wide Band Damping Factor
Greater than 40

Power Requirements

100 Volts, 50/60Hz at 12 amps
110 Volts, 50/60Hz at 11 amps
120 Volts, 50/60Hz at 10 amps
220 Volts, 50/60Hz at 5 amps
230 Volts, 50/60Hz at 5 amps
240 Volts, 50/60Hz at 5 amps

Nate: Refer to the rear panel of the MC402f0r the correct
voltage

Overall Dimensions
17-1/2 inches (44.45cm) W, 9-7/16 inches (23.97am) H, 20
inches (50.8cm) D, including clearance for connectors

Weight
110.5 pounds (50.1kg) net, 143.5 pounds (65.1kg) in ship-
ping carton

NOTES

1. The heavy notes 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. AC input at 120 volts, 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. Capacitor values are microfarads (uF).
c. Inductor values are in microhenries (UH).

4. On PC board drawings, Square pad indicates:

a. Polarized Capacitors - Positive
b. Diodes - Cathode
0. Others - Pin 1

i WARNlNG
Parts marked with the symbol A have critical

characteristics. Use only replacement parts recom-
mended by the manufacturer.

L.

Page 36

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REF

SCREW MACH SEMS 6-32 X 5/16 PH PN
SCREW TAPPING 4-40 X 1/4
S[HBPAJJEL

LOGO BALTJJGHT

LOCK) PUSIIBIJTTCHJILACDKIJCHTF
ASSY JNDICAT OR PCB

LOCKING PCB SUPPORT 7/8"
LOCKING PCB SUPPORT 5/8
SWHCHPOWER

BUSHING SWITCH

WASHER TNT STAR 3/8 X .507 X .002
SCREW MACH 4-40 X 1/4 PH PN BLK
LIETTER

BALH

RIETTHK PINXFE

ASSY METER LED PCB

SPACER #6 X 3/16 STEEL

NUT MACH 6-32 W/LOCK
DUSTCOVER

DECALTOPCOVER

SCREW MACH 10-32 X 1/2 PH TRUSS HD
CHASfiS

SCREW TAP 8-32 X 5/16 PH PN BLK

36
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36

SCREW TC 6-32 X 1/4 PH FL U/C
POTTED TRANSFORMER OUTPUT
POTTED TRANSFORMER POWER
DECAL OUTPUT TRANSFORMER
DECAL POWER TRANSFORMER
GROMMET 3/

HEATSINK

ISOSTRATE POWER SUPPLY
SPACER PCB 1/

CLIP TRANSISTOR 218

CLIP TRANSISTOR 214

AS SY HEATSINK PCB

SCREW SM 6 X 5/8 PH PN TYPE A
HEATSINK COVER LEFT
HEATSINK COVER RIGHT

ST 6-32 X 5/16

SU'EREAR PANEL

SCREW TAPTITE 6-32 X 1/4 PH PN BLK
SCREW MACH SEMS 8-32 X 1/4
ASSY CAPACITOR PCB

SCREW, MACH SEMS 10.32 X 3/8
COVER CAPACITOR

REAR PANEL

SCREW SM 4-24 X 1/2 PH PN TYPE A
WASHER INT STAR #4

ASSY INPUT PCB

CAP ELECT 54001112 75VDC

CLAMP CAPACITOR

SCREW MACH 6-32 X 1/2 PH PN
NUT KEP 6-32 SPECIAL

ASSY METER PCB

NUT KEP 440 CADMIUM PLATE
TERMINAL BLOCK AC

WASHER FLAT STEEL 4 X 9/32 X .025
WASHER LOCK 5 X .255 INT STAR
NUT MACH 440 X 3/16 X 1/16
ASSY DRIVER PCB

SHIELD PCB

HEATSINK VENT

SCREW TOG-32 X 1/2 PH PN TYPE F
WASHER FLAT STEEL 6 X 3/8 X .032
PLASTIC CUPPED PCB SUPPORT 3/8
SPACER STEEL 4 X 3/8 L NCKL PLT
GROMMET

NUT MACH 10-32 W/LOCK

NUT MACH 8-32 W/LOCK
HOLDER CABLE TIE

CABLE TIE PANDUIT PLTIM-M
BRACKET CHASSIS SUPPORT
DIODE BRIDGE RECTIFIER

PAD THERMAL

BOTTOM COVER

RECEPTACLE Ac LINE ..

HOLDER FUSE SOCKET UL/CSA
POST BINDING RED

POST BINDING ELK _ ,

NUT GOLD SUPPLIED W/ll7758
WASHER LOCK INT TOOTH

NUT HEX M9 X .75 GOLD PLATED
SCREW MACH 10432 X 3/4 PH PN
WASHER FLAT #10 CLEAR ZINC
FOOT PLASTIC BLACK ,