McIntosh MA-6500 Service manual

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Page 1

INTEGRATED AMPLIFIER

WATTS

2.0

DECIBELS

TUNER MUTEVIDEO LOUDPH AUX/TAP E

200

TREBLEBASS

LEFT RIGHT

SEN SOR

CD 2 MONO SPEAKERSCD 1

POWER OUTPUT

CONTENTS

Performance Specifications ........................................ 2

Notes ......................................................................... 3

Rear Panel .................................................................. 4

Section Location ........................................................ 4

Block Diagram ...................................................... 5 - 8

Interconnection Diagram .................................... 9 - 10

Input Driver Schematic and PCB ....................... 11 - 18

Heatsink Schematic and PCB ............................ 19 - 20

WATTS

2.0

DECIBELS

200

VOLUME

POWE R GUARD

HEADPHON ES

POWER OUTPUT

BALANCE

Lamp Schematic and PCB ................................. 19 - 20

PG Display Schematic and PCB ........................ 21 - 22

Control Schematic and PCB .............................. 21 - 22

Tone Schematic and PCB .................................. 23 - 26

Parts List ............................................................ 25 - 28

Exploded View and Parts List ............................. 29 - 31

Repacking Instructions ............................................. 33

STANDBY ON

SERVICE MANUAL

Page 2

PREFORMANCE SPECIFICATIONS

POWER OUTPUT, STEREO

250, 200, 120 watts minimum sine wave continuous average power output per channel, both channels operating, into a load impedance of 2, 4 and 8 ohms respectively.

TOTAL HARMONIC DISTORTION

0.005% maximum at any power level from 250 milliwatts to rated power per channel from 20Hz to 20,000Hz, both channels operating.

INTERMODULATION DISTORTION

0.005% maximum if instantaneous peak power output per channel does not exceed twice the rated output with both channels operating for any combination of frequencies from 20Hz to 20,000Hz.

OUTPUT LOAD IMPEDANCE

2, 4 or 8 ohms

RATED POWER BAND

20Hz to 20,000Hz

DYNAMIC HEADROOM

2.4dB at 2, 4 or 8 ohms

DAMPING FACTOR

60 at 2 ohms 120 at 4 ohms 230 at 8 ohms

FREQUENCY RESPONSE

+0, -0.5dB from 20Hz to 20,000Hz

SIGNAL TO NOISE RATIO, (A WEIGHTED)

Phono Input: 90dB (84dB IHF) below 10mV input High Level: 100db (90dB IHF) below rated output Power Amplifier: 110dB below rated output

SENSITIVITY

Phono: 2.5mV for 2.5V rated output (0.5mV IHF) High Level: 250mV for 2.5V rated output (50mV IHF) Power Amplifier Input: 2.5V for rated output

INPUT IMPEDANCE

Phono: 47k ohms, 65pF High Level: 22k ohms

MAXIMUM INPUT SIGNAL

Phono: 90mV High Level: 8V

POWER REQUIREMENT

120V, 50/60Hz, 5.0 Amps UL/CSA 230V, 50/60Hz, 2.5 Amps

PREAMPLIFIER MAXIMUM VOLTAGE OUTPUT

Phono: 90mV at tape output High Level: 8V at tape output Main Out: 8V at preamp output

VOLTAGE GAIN

High Level to Tape: 0dB High Level to Main: 20dB

TONE CONTROLS

Bass Control: +/-12dB at 20Hz Treble Control: +/-12dB at 10kHz

POWER REQUIREMENTS

100 Volts, 50/60Hz at 4.8 Amps 110 Volts, 50/60Hz at 4.4 Amps 120 Volts, 50/60Hz at 4.0 Amps 220 Volts, 50/60Hz at 2.0 Amps 230 Volts, 50/60Hz at 2.0 Amps 240 Volts, 50/60Hz at 2.0 Amps

NOTE: Refer to the rear panel of the MA6500 for the correct voltage.

DIMENSIONS

17-1/2 inches (44.5cm) wide by 7-1/16 inches (17.9cm) high. Depth behind front panel is 18-1/8 inches (46cm) including connectors. Knob clearance required in front of the mounting panel is 1-1/8 inches (2.9cm).

Page 3

NOTES

MA6500

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).

4. On PC Board Drawings, Square Pad Indicates: a. Polarized Capacitors - Positive b. Diode - Cathode c. Others - Pin 1

5. The voltages enclosed in a box are signal voltages that are measured with a 2.5mV, 1kHz signal connected to both channels at the TUNER input jacks.

Front panel controls are set at:

BALANCE .................................... CENTER DETENT

TREBLE BASS .............................CENTER DETENT

INPUT SELECTORS...................................... TUNER

LOUDNESS .......................................................... OFF

POWER ................................................................... ON

VOLUME .................................FULLY CLOCKWISE

MONO................................................................... OFF

SPEAKER SWITCHES 1 AND 2........................... ON

Rear panel controls are set at:

PROCESSOR ........................................................OUT

PWR AMP INPUT ................................................. INT

SPEAKER TERMINALS .................... NO LOAD ON

OUTPUTS

6. WARNING: Parts marked with the symbol have critical characteristics. Use ONLY replacement parts recommended by the manufacturer.

Page 4

WARNING

SHOCK HAZARD - DO NOT OPE N. FOR CONTINUED PROTECTION AGAINST FIRE HAZARD REPLACE ON LY W ITH SAM E T YPE AND RATING FUSE.

AVIS

RISQUE DE CHOC - EL ECTRIQUE - NE PAS OUVRIR. REMPLAC ER PAR UN FUSIBLE DE MEME TYPE, AM PERAGE ET VOLTAGE.

WARNING

RISK OF HAZARDOUS ENERGY!MAKE PROPER SPEAKER CONNECTIONS.SEE OPERATING MANU AL BEFORE USING.

AVIS

ENERGIE ELECTRIQUE DANGEREUSE! VOIR LE

CAHIER D’INSTRUCTION.

120V 50/60H z 4A

REAR PANEL

RIGHT RIGHTLEFT LEFT

M A 650 0 I N T E G R AT E D A M P LIF IE R

McINTOSH LABORATORY, INC., BINGHAMTON, NEW YORK MADE IN USA

SERIAL

NUMBER

T 10AL 250V

SLO BLO

EXT SENSOR

HEATSINK

PCB

POWER

CONTROL

DATA PORTS IN PU TS

VIDEO

TUNER

CD 2

SUM

HOME

TAPE

POWER AMP IN

CD 1

LLL

AUX

RRR

EXTPHINT

POWER

AMP INPUT

MAIN OUT

TAP E

OUT

SECTION LOCATIONS

TAPE VIDEO CD 2 CD 1 GNDPH AUX

TUNER

IN P UT /D R IV E R

PCB

AUX

LAM P

PCB

TON E

PCB

6 5

CONTROL

PCB

PG D ISPLAY

Page 5

BLOCK DIAGRAM

MA6500

CHANNEL

INPUTS

RIGHT

CHANNEL

INPUTS

PORTS

LEFT

DATA

CD1

CD2

TUNER

VIDEO

TAPE

AUX

PHONO

AUX

TAPE

VIDEO

TUNER

CD2

CD1

POWER

CONTROL

AUX

TAPE

VIDEO

TUNER

CD2

CD1

SUM

HOME

R IAA

AMP

R IAA

AMP

INPUT

ELECTRO-

MAGNETIC

SWITCHING

INPUT

ELECTRO-

MAGNETIC

SWITCHING

DATA

PORT

INPUT

SELECTOR

LOGIC

MICRO

CONTROLLER

EXT IR

SENSOR

COMPENSATION

SENSOR

LOUDNESS

CONTROL

LOUDNESS

CONTROL

MONO

SWITCHING

MONO

SWITCHING

120VAC

50/60Hz

SUPER TRACKING

VOLUME CONTROL

SUPER TRACKING

VOLUME CONTROL

MAIN

FUSE

20dB

AMP

20dB

AMP

IN RUSH

CURRENT

LIMITER

BALANCE

CONTROL

CONTROLS

BALANCE

CONTROL

POWER

TRANSFORMER

TONE

AMP

TONE

AMP

RECTIFIERS

AND FILTERS

LAMP CONTROL

TURN-ON

DELAY

LOGIC

LAMP

FUSE

OUTPUT

MUTING

OUTPUT

MUTING

LOGIC

OUTPUT

MUTING

FRONT PANEL

LAMPS

HEAD-

PHONE

AMP

TO PREAMP IN (INT)

PREAMP OUT RIGHT

HEAD-

PHONE

AMP

TO PREAMP IN (INT)

PREAMP OUT LEFT

5.6V

REGULATOR

15V

REGULATOR

-15V

REGULATOR

MATCHING

NETWORK

5.6V

15V

-15V

11.5VAC

HEAD

PHONE

THERMAL

PROTECTION

MAIN

RELAYS

MAIN

SUPPLY

B+

B-

Page 6

BLOCK DIAGRAM

LEFT PG

INDICATOR

DRIVER

POWER

GUARD

DIFF

AMP

CASCODE

VOLTAGE

AMP

POSITIVE

CURRENT

LIMITER

+++

PREDRIVER

DRIVER OUTPUT

SPEAKER

SWITCHING

LEFT

OUTPUT

SPEAKER 1

SPEAKER 2

PRE AMP LEFT

(INT)

PRE AMP RIGHT

(INT)

TO PRE AMP

OUT (INT)

PRE AMP IN

(EXT)

PRE AMP IN

(EXT)

TO PRE AMP

OUT (INT)

POWER AMP

INPUT

SWITCH

POWER AMP

INPUT

SWITCH

RIGHT PG

INDICATOR

TO MICRO CONTROLLOR

DRIVER

ELECTRONIC

ATTENUATOR

ELECTRONIC

ATTENUATOR

POWER

GUARD

CURRENT

SOURCE

DIFF

AMP

DIFF

AMP

CURRENT

SOURCE

DIFF

AMP

CASCODE

VOLTAGE

AMP

CASCODE

VOLTAGE

AMP

CASCODE

VOLTAGE

AMP

BIAS

---

PREDRIVER DRIVER OUTPUT

NEGATIVE

CURRENT

LIMITER

NEGATIVE

CURRENT

LIMITER

---

PREDRIVER DRIVER OUTPUT

BIAS

+++

VOLTAGE

LOG

AMP

NEGATIVE

FEEDBACK

NEGATIVE

FEEDBACK

VOLTAGE

LOG

AMP

OUTPUT DRIVER PREDRIVER

RECTIFIER

AMP

LEFT

METER

RIGHT

METER

TURN ON

DELAY

SPEAKER

SWITCHING

THERMAL

PROTECTION

RIGHT

OUTPUT

SPEAKER 1

SPEAKER 2

POSITIVE

CURRENT

LIMITER

Page 7

INTERCONNECT

MA6500

100

Page 8

INPUT DRIVER

049193 SH 1 OF 3

Page 9

MA6500

INPUT DRIVER

049193 SH 2 OF 3

Page 10

INPUT DRIVER

049193 SH 3 OF 3

Page 11

MA6500

INPUT DRIVER

Page 12

3A 3B

HEATSINK

049194

4B4A

LAMP

049235

Page 13

MA6500

PG DISPLAY

049236

CONTROL

049195

Page 14

TONE

049268

240

Page 15

MA6500

TONE

049268

PARTS LIST

PART NO DESCRIPTION REFERENCE NO

049193 INPUT DRIVER

003611 CARD MOUNTING BRACKET SP1 SP2 061196 DISC CAP 47PF,20%,N470 50V C146 C152 C157 C159 061199 DISC CAP 100PF 10% N1500 50V C58 C61 C72 C73 C74

C75 C76 C78 C140 C141

C156 C158 061248 DISC CAP .1MF,25V,Y5T C32 C33 C55 061268 MONO CAP .1UF,50V,Z5U C62 C63 C64 C65 C66

C67 C68 C69 C70 C71

C161 C162 C171 C172 061273 220PF 5% 100V NPO C173 C174 C175 064254 M POLY FILM CAP .1MF,10%,100V C129 064267 M. POLYESTER CAP .22MF,400V C145 064312 CAP M POLY .01UF 5% 63VDC C165 C167 064318 CAP M POLY .033UF 5% 63/100VDC C166 C168 064364 CAP POLYPROP .047MF 10% 250V C47 C144 066269 CAP ELECT 1UF 10% 50V C115 C116 066309 CAP ELECT 1000UF 10V C132 066330 CAP ELECT 220UF 16V SHORT CAN C163 C164 066344 CAP ELECT 100UF 25V C133 C134 066360 CAP ELECT 3300UF 35V C125 C127 C128 066361 CAP ELECT 1000UF 20% 35V C126 066445 ELECT CAP 10MF, 50V AMMO PACK C30 C85 C86 C87 C88

C89 C90 C91 C93 C94

C95 C96 C97 C98 C99

C100 C102 C103 C104

C105 C106 C115 C117

C118 C123 C124 C153

C154 C177 066446 ELECT CAP 47MF, 35V AMMO PACK C92 C101 066447 ELECT CAP 100MF 16V AMMO PACK C22 C40 C119 C120

C121

066462 ELECT CAP 1O UF 100VDC AMMO C35 C36 C37 C38 066469 ELECT CAPACITOR 470MF 50V T&R C176 066504 CAPACITOR ELECT 25000UF 75V C142 C143 070047 SILICON DIODE 1N4148 T&R D1 D3 D4 D5 D6 D7 D8

D9 D10 D21 D22 D25

D26 D27 070130 ZENER DIODE 8.2V,1/2W D2 070131 DIODE RECTIFIER D11 D12 D13 D14 D15

D16 D23 D24 070139 RECTIFIER BRIDGE MC1000 D28 087050 REED RELAY FORM 1A,5V,500 OHMS K2 K3 K4 K5 K6 K7 K8

K9 K10 K11 K12 K13

K16 K17 K18 K20 087057 RELAY K1 K21 087069 POWER RELAY TV5 24V K24 087072 RELAY 24V TV8/VDE CERTIFIED K22 K23 089089 FUSE 2A SLO-BLO 5X20 F1 117215 4-PIN CONNECTOR J3 J8 117219 MALE CONN 10 POS J1 117244 FRICTION LK CONN 9POS MALE J6 J7 117279 11-POS. MALE CONN. J2 117404 HEADER 2-PIN 0.156 J4 J5 117436 PJ261G PHON JACK, GOLD J23 117455 PHONO JACK 8P, GOLD PLATED J21 J22 117494 MINI JACK J28 117549 HEADPHONE JACK DUAL BLACK 1/8 J24 J25 J26 J27 117708 FASTON BLADE W/FEET J10 J11 J12 J13 J14 J15

J16 J17 J18 J19 J2 117712 FASTON BLADE .110 J20 117717 MTA-156 HEADER 8PIN J9 122297 CHOKE OUTPUT .65UH L2 L3 132172 TRANSISTOR SI PNP MPSA55 Q50 132193 TRANSISTOR J.F.E.T. 2N4392 Q62 Q64

132223 TRANSISTOR NPN MPS4124 2K/REEL Q44 Q46 Q47Q57 Q58

Q59 Q61Q63 Q66 Q75 Q78 Q79 Q80 Q81 Q83 Q87 Q88

132224 TRANSISTOR PNP Q1 Q40 Q48 Q49 Q52

Q69 Q73 Q74 Q76 Q77

132254 TRANSISTOR NPN Q54 Q55 Q56 Q67 Q68

Q71 Q85 Q86

132255 TRANSISTOR PNP Q2 Q51 Q53 Q65 Q70

Q72 132261 TRANSISTOR PNP Q18 Q82 132262 TRANSISTOR NPN Q17 Q84 133028 IC OPERATIONAL AMPLIFIER IC1 IC3 133067 NE5534AN OP AMP LOW NOISE IC16 IC17 133108 IC +5V REGULATOR IC5 133153 IC REGULATOR -15V IC6 133154 IC REGULATOR 15V IC7 133175 IC AND 2 INPUT X 4 IC14 133180 LB1720 8 LN DRIVER ARRAY IC10 IC13 133186 IC SHFT REG SER-PAR IC9 IC11 IC12 133260 DUAL OPERATIONAL AMPLIFIER IC2 IC4 IC15 133360 OCTAL DAR TRANS ARRAY W/DIODE IC8 134389 TRIM POT 100K,10%,3/8SQ. R237 R238 137042 FLAMEPROOF RES 47 OHM 5% 1/4W R56 R60 141165 RES CF 10 5% 1/2W R77 R79 R119 R230

R231 R232 144053 RES MF 10K 1% 1/4W R122 R134 R171 R217

R218 144071 METAL FILM RES 365 OHM 1% 1/4W R265 R266 R267 R268

R269 R270 R271 R272 144086 METAL FILM RES 475 OHM 1% 1/4W R45 R167 R168 R187 144090 METAL FILM RES 1K 1% 1/4W R36 R164 R170 R184

R241 R242 R249 R255

R262 R263 R264 144095 RES MF 3.32K 1% 1/4W R41 R55 R188 R193

Page 16

PARTS LIST

con’t

144097 METAL FILM RES 4.75K 1% 1/4W R46 R86 R177 R222

R227 R233 R234 144107 METAL FILM RES 40.2K 1% 1/4W R161 R192 144108 RES MF 47.5K 1% 1/4W R29 R62 R65 R66 R69

R175 R181 R182 R247

R251 144113 RES MF 100K 1% 1/4W R100 R162 R196 R228 144119 METAL FILM RES 332K 1% 1/4W R221 R226 144125 METAL FILM RES 150K 2% 1/4W R169 R190 144127 METAL FILM RES 95.3K 1% 1/4W R248 R257 144141 METAL FILM RES 27.4K 1% 1/4W R219 R223 144154 RES MF 12.1K 1% 1/4W R128 R172 144160 METAL FILM RES 22.1OHM 1% 1/4W R152 R156 144172 RES MF 221 OHMS 1% 1/4W R51 R53 R145 R146

R160 R186 R239 R240 144187 METAL FILM RES 22.1K 1% 1/4W R104 R105 144191 RESISTOR MF 1.21K 1% 1/4W R38 R101 R159 R173 144196 METAL FILM RES 100 OHM 1% 1/4W R67 R68 R136 R137

R138 R139 R140 R141

R142 R144 R150 144210 RES MF 7.5K 1% 1/4W CRB1/4FX R245 R253 144220 95.3 OHMS 1% 1/4W MF R246 R256 144225 MF RES, 30K OHM 1% 1/4W R147 R148 R258 R259 144262 RES NETWORK, 2X220K, ISO R1 R2 R3 R4 R5 R6 R7

R154 R243 144264 METAL FILM RES 10M 1% 1/4W R220 R224 144265 METAL FILM RES 2.21M 1/4W R225 R229 144273 RESISTOR MF 182 OHM 1/4W 1% R157 R205 144338 RES MF 324 OHM 1% 1/4W R163 R194 144378 RES MF 2.21 OHM 1/4W 1% R250 R252 144440 MF RES 14.3K 1% 1/4W R50 R165 144441 METAL FILM RES 274K 1% 1/4W R52 R158 R176

R178 R179 R195 144442 METAL FILM RES 47.5 1% 1/4W R244 R254 144443 METAL FILM RES 681K 1% 1/4W R30 R37 R83 R166 R174 148059 SLIDE SWITCH S1 S2 178159 FUSE HOLDER 5X20MM PCB MOUNT F1

049194 HEATSINK

061023 DISC CAP 100PF 10% N1500 C7 C8 061159 CERAMIC CAP .01MF +80-20% 50V C9 C16 061248 DISC CAP .1MF,25V,Y5T C3 C5 064363 CAP POLYPROP 0.15MF 10% 250VDC C10 066446 ELECT CAP 47MF, 35V AMMO PACK C1 C2 070047 SILICON DIODE 1N4148 T&R D1 D2 D3 D4 D5 070133 DIODE 200V,6A D6 D7 117213 2-PIN MALE CONNECTOR J3 117244 FRICTION LK CONN 9POS MALE J1 117404 HEADER 2-PIN 0.156 J2 132223 TRANSISTOR NPN MPS4124 2K/REEL Q1 132224 TRANSISTOR PNP Q2 132261 TRANSISTOR PNP Q7 132262 TRANSISTOR NPN Q6 134390 TRIM POT 200 OHM 20% HORIZ AD R13 137093 MET OX 680 5% .5W R2 R9 137094 MET OX 1.8K 5% .5W R6 R11 137095 MET OX 430 5% .5W R7 137096 MET OX 47 5% .5W R12 139177 WIREWOUND RES 0.5 OHM 5W 5% R31 R32 R33 R34 R35

R36 R37 R38 144053 RES MF 10K 1% 1/4W R3 R10 144172 RES MF 221 OHMS 1% 1/4W R1 R8 144279 THERMISTOR 100 OHM RT1 144378 RES MF 2.21 OHM 1/4W 1% R30

049195 CONTROL

058153 INCANDESCENT LAMP 14V 100MA DS13 DS14 DS15DS16

DS17 DS18 061268 MONO CAP .1UF,50V,Z5U C3 C5 C6 C7 C10 061273 220PF 5% 100V NPO C8 C9 061277 MONO CAP 0.1MF 20% 50V C1 066254 CAP ELECT 220UF 50V 20% C2 066330 CAP ELECT 220UF 16V SHORT CAN C4 070093 LED LAMP RED DS1 DS2 DS3 DS4 DS5

DS6 DS7 DS8 DS9 DS10

DS11 DS12 117216 MALE CONN 5-PIN 0.1 POST ASSY J4 117279 11-POS. MALE CONN. J1 117462 PHON JACK 1 1/8” STEREO VER J3 121031 IR SENSOR 38KHZ MT1 133175 IC AND 2 INPUT X 4 IC1 133186 IC SHFT REG SER-PAR IC3 IC4 133191 IC DC MOTOR DRIVER IC2 133241 IC MICROPRCSSR RESET POS IC6 133394 PROGRAMMED DEVICE 144053 RES MF 10K 1% 1/4W R5 R16 144090 METAL FILM RES 1K 1% 1/4W R14 R15 144113 RES MF 100K 1% 1/4W R2 144157 METAL FILM RES:10 OHMS 1% 1/4W R4 144196 METAL FILM RES 100 OHM 1% 1/4W R1 144290 RES NETWORK 3 X 10K BUSSED R6 144338 RES MF 324 OHM 1% 1/4W R7 R8 R9 R10 R11 R12

R13 144378 RES MF 2.21 OHM 1/4W 1% R19 144444 METAL FILM RES 75 1% 1/4W R 3 150058 TACT SWITCH S1 S2 S3 S4 S5 S6 S7 S8

S9 S10 S11S12 178139 IC SOCKET 24-PIN IC5 180039 CERAM RESON 6.0MHZ W/CAP Y1

049235 LAMP

058120 LAMP 14V #7373 DS1 DS2 DS3 117240 4 PIN RT. ANGLE J1 117274 CONN. 2 POS. R-ANGLE J2

049236 POWER GUARD

058133 AMBER LED DS1 DS2 058153 INCANDESCENT LAMP 14V 100MA DS3 DS4 117215 4-PIN CONNECTOR J2 J3 J4 117216 MALE CONN 5-PIN 0.1 POST ASSY J1

049268 TONE

061191 DISC CAP 22PF,10%,NPO 50V C3 C4 061196 DISC CAP 47PF,20%,N470 50V C16 C17 061256 M.CAP 470PF,5%,100V C26 C27 C38 C39 061260 MONOLYTHIC, 220PF C1 C2 061268 MONO CAP .1UF,50V,Z5U C28 C30 C31 C33 C36

C37 064254 M POLY FILM CAP .1MF,10%,100V C5 C6 064318 CAP M POLY .033UF 5% 63/100VDC C18 C19 C20 C21 064329 CAP M POLY .22UF 5% 63VDC C40 C41 C42 C43 066330 CAP ELECT 220UF 16V SHORT CAN C44 C45 066345 CAP ELECT 22UF 50V C9 C12 066378 CAP ELECT 47UF 16V BP C15 066445 ELECT CAP 10MF, 50V AMMO PACK C7 C10 C11 C14 C34

C35 066446 ELECT CAP 47MF, 35V AMMO PACK C22 C2324 C25 070047 SILICON DIODE 1N4148 T&R D1 D2 087050 REED RELAY FORM 1A,5V,500 OHMS K1 K2 K3 117219 MALE CONN 10 POS J1 117707 CONNECTOR MALE 6 POS RT ANGLE J2

133260 DUAL OPERATIONAL AMPLIFIER IC1 IC2 IC3 IC4 134457 POT, EQUAL R33 R34 134464 POTENTIOMETER BALANCE 2KOHM R32 134490 POTENTIOMETER 50KAX2 R1 144015 METAL FILM RES 33.2K 1% 1/4W R23 R25 144053 RES MF 10K 1% 1/4W R9 R27 144086 METAL FILM RES 475 OHM 1% 1/4W R14 R28 144090 METAL FILM RES 1K 1% 1/4W R6 R11 R13 R17 144095 RES MF 3.32K 1% 1/4W R21 R22 144107 METAL FILM RES 40.2K 1% 1/4W R39 R40 144113 RES MF 100K 1% 1/4W R12 R15 R16 R29 R36

R38 144157 METAL FILM RES 10 OHMS 1% 1/4W R8 R10 144160 METAL FILM RES 22.1OH 1% 1/4W R2 R26 144195 MF RES, 681 OHM 1% 1/4W R5 R20 144196 METAL FILM RES 100 OHM 1% 1/4W R35 R37 144298 MF 2.21K 1% 1/4W R30 R31 144304 MF 2.74K 1% 1/4W R3 R18 R19 R24 144364 RES MF 475K 1% 1/4W R4 R7

280

Page 17

EXPLODED VIEW

MA6500

Page 18

EXPLODED VIEW PARTS LIST NOTES

Ref. Part Description No. No.

1 016404 FRONT PANEL GLASS 2 004899 EXTRUSION BRACKET 3 018612 END CAP 4 101042 TS 4-40 X 1/2 SLOT FILLISTER 5 171260 C/A INPUT/POWER SWITCH 6 017531 PUSHBUTTON ASSY RED 7 017517 PUSHBUTTON ASSY 8 017736 HEADPHONE BEZEL 9 078033 O-RING 10 090258 KNOB 25mm INDEX 11 104073 FELT W MPI-4 1/4 X 5/8 12 018605 BOTTOM EXTRUSION 13 101172 TCS 6-32 X 1/4 PHIL FLAT U/C 14 101054 TS 6-32 X 1/4 PHIL PAN TAPTITE 15 018587 TOP EXTRUSION 16 094350 SENSOR GASKET 17 017764 DISPLAY PLEXIGLAS 18 022314 FISHPAPER SHEILD 19 017363 PLEXIGLAS FILTER LIGHT BLUE 20 004966 SUBPANEL 21 049195 CONTROL PCB ASSY 22 129284 TONE PCB ASSY 23 100275 MS 6-32 X 1/2 PHIL BLK TRUSS HD 24 021030 SPACER 6 X 1/4 25 078031 GROMMET 26 049236 POWER GUARD DISPLAY ASSY 27 021094 SPACER 4 X 1/4 28 102001 KEP NUT 4-40 CADMIUM PLATE 29 124074 MC202 METER 30 092341 FILTER AZURE BLUE 31 092342 FILTER PALE BLUE 32 017447 PLASTIC LIGHT BOX 33 049235 LAMP PCB ASSY 34 114072 PLASTIC RIVET 35 159310 POWER TRANSFORMER 36 102007 MACH NUT 1/4-20 W/LOCK 37 004964 TRAY 38 102003 MACH NUT 6-32 W/LOCK 39 004965 CHASSIS 40 017218 PLASTIC FEET - BLACK 41 104080 FLAT WASHER #10 CLEAR ZINC 42 100159 MS 10-32 X 3/4 PHIL PAN ZINC 43 101176 TCS 6-32 X 1/2 PH PAN BLK TYPE F 44 074091 AC TERMINAL BLOCK 45 104001 FLAT STEEL WASHER #4 X 9/32 X .025 46 104004 LK WASHER 5 X .255 INT STAR 47 102022 MN 4-40 3/16 X 1/16 48 112038 STL SPACER 4 X 3/8 L NICKEL PLT 49 021038 SPACER #6 X 3/8 50 084135 THERMAL PAD MC7150 51 106007 SPRING CLIP LATCH TYPE 52 049194 HEATSINK PCB ASSY

53 101059 SM 6 X 5/8 PHIL PAN TYPE A 54 114119 TRANSISTOR CLIP 214 55 114118 TRANSISTOR CLIP 218 56 112087 PCB SPACER 1/4” 57 084194 ISOSTRATE 58 018616 AMPLIFIER HEATSINK 4 INCH 59 017160 MOUNTING TAB W/.140 DIA MTG 60 049193 INPUT/DRIVER PCB ASSY 61 102014 MACH NUT 6-32 W/LOCK 62 110009 NUT M5 X 0.8 BRASS W/GOLD PLATE 63 104130 LW #10 SPLIT PHOS/BRONZE 64 104148 FLAT WASHER BRASS 65 004800 OUTPUT PLATE 66 100250 SEMS 6-32 X 1/4 PHIL PAN 67 102020 MACH NUT 6-32 SELF-LOCK 68 104016 LK WASHER 1/2 X .630 X .022 INT STAR 69 178122 SOCKET FUSEHOLDER UL/CSA 70 117487 MC1000 AC LINE RECEPTACLE 71 117369 COAX RECEPTACLE GOLD TYPE F 72 101197 HI/LO 4-32 X 3/8 PH ROUND BLACK 73 084124 DUAL BINDING POST 74 084112 GROUND POST (GOLD) 4300 75 004962 REAR PANEL 76 101109 TS 6-32 X 5/16 PHIL PAN 77 004798 TOP COVER 78 101078 TS 8-32 X 5/16 PHIL PAN 79 017706 TERMINAL COVER 80 100072 LOCK WASHER 1/4 X .396 INT STAR 81 100126 MS 1/4-20 X 5/8 PHIL PAN BLACK 82 094017 FOAM TAPE 1/4 X 1/4

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REPACKING INSTRUCTIONS

Page 20

INTEGRATED AMPLIFIER

SERVICE MANUAL

The continuous improvement of it’s products is the policy of McIntosh Laboratory Incorporated, who reserve the right to improve design with out 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 040703