Service Manuals, User Guides, Schematic Diagrams or docs for : . Rare and Ancient Equipment Mc INTOSH Audio MA6900 hfe_mcintosh_ma6900_service
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INTEGRATED AMPLIFIER
CONTENTS
Performance Specifications ........................................ 2 Capacitor Schematic and PCB ........................... 21 - 22
Notes ......................................................................... 2 Control Schematic and PCB .............................. 23 - 26
Rear Panel .................................................................. 3 Lamp Schematic and PCB ................................. 25 - 26
Section Location ........................................................ 4 Tone Schematic and PCB .................................. 27 - 31
Block Diagram ...................................................... 5 - 6 Keyboard Schematic and PCB ........................... 30 - 32
Interconnection Diagram ...................................... 7 - 8 Parts List ............................................................ 33 - 36
Main Schematic and PCB .................................... 9 - 18 Exploded Views and Parts Lists .......................... 37 - 40
Balanced Schematic and PCB .............................. 12, 18 Repacking Instruction .............................................. 41
Heatsink Schematic and PCB ............................. 19 - 20
SERVICE MANUAL
PERFORMANCE SPECIFICATIONS
Power Output Input Impedance
Minimum sine wave continuous average power output per Phono, 47k ohms, 65pF
channel, all channels operating is: High Level, 22k ohms
200 watts into 2 ohm load
200 watts into 4 ohm load Maximum Input Signal
200 watts into 8 ohm load Phono, 90mV
High Level, 8V
Rated Power Band
20Hz to 20,000Hz Preamplifier Maximum Voltage Output
Phono, 8V at tape output
Total Harmonic Distortion High Level, 8V at tape output
Maximum Total Harmonic Distortion at any power level Main Out, 8V at preamp output
from 250 milliwatts to rated power output is:
0.005% for 2, 4 or 8 ohm loads Voltage Gain
High Level to Tape: 0dB
Dynamic Headroom High Level to Main: 20dB
2.4dB
Wide Band Damping Factor
Frequency Response Greater than 40
+0, -0.5dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz Power Requirements
100 Volts, ~ 50/60Hz at 4.8 amps
Sensitivity 110 Volts, ~ 50/60Hz at 4.4 amps
Phono, 2.5mV for 2.5V rated output (0.5mV IHF) 120 Volts, ~ 50/60Hz at 4.2 amps
High Level, 250mV for 2.5V rated output (50mV IHF) 220 Volts, ~ 50/60Hz at 2.0 amps
Power Amplifier Input, 2.5V for rated output 230 Volts, ~ 50/60Hz at 2.0 amps
240 Volts, ~ 50/60Hz at 2.0 amps
Signal To Noise Ratio (A Weighted) Note: Refer to the rear panel of the MA6900 for the correct voltage.
90dB (84dB IHF) below 10mV input, Phono Input
100dB (90dB IHF) below rated output, High Level Overall Dimensions
110dB below rated output, Power Amplifier Front Panel: 17-1/2 inches (44.45cm) wide, 7-1/8 inches
(18.10cm) high. Depth behind front mounting panel is 16-1/2
Intermodulation Distortion inches (41.91cm). Clearance required in front of the Front Panel
Maximum Intermodulation Distortion if instantaneous peak is 1 inch (2.54cm) for knobs.
output per channel does not exceed twice the rated output,
for any combination of frequencies from 20Hz to 20,000Hz, Weight
with all channels operating is: 74.5 pounds (33.8 Kg) net, 92.5 pounds (41.7 Kg) in shipping
0.005% for 2, 4 or 8 ohm loads carton
NOTES
1. The heavy lines on the schematic denote the primary 4. On PC board drawings, Square pad indicates:
signal path. a. Polarized Capacitors - Positive
b. Diodes - Cathode
2. Unless otherwise noted, all voltages indicated on the c. Others - Pin 1
schematics are measured under the following conditions:
a. AC input at 120 volts, 50/60Hz. 5. WARNING
b. All voltages are +/-10% with respect to ground. A Parts marked with the symbol have critical
high impedance (10 megaohm) voltmeter must be used. characteristics. Use only replacement parts recom-
mended by the manufacturer.
3. Unless otherwise specified:
a. Resistor values are in ohms.
b. Capacitor values are microfarads (uF).
c. Inductor values are in microhenries (uH).
2
MA6900
REAR PANEL
3
SECTION LOCATIONS
TOP VIEW WITH COVER REMOVED
BOTTOM VIEW WITH COVER REMOVED
4
MA6900
BLOCK DIAGRAM
5 6
1 INTERCONNECT
TB1
7 8
MA6900
2 MAIN 049688 1 OF 3
9 10 11
2 MAIN 049688 2 OF 3
3 BALANCED
12 13 14
MA6900
2 MAIN 049654 3 OF 3
15 16
2 MAIN 049654
3 BALANCED 049654B
17 18
MA6900
4A 4B HEATSINK 049665
19 20
5 CAPACITOR 049653
21 22
MA6900
6 CONTROL 049655
23 24
6 CONTROL PCB 049655
7A 7B LAMP 049235
25 26
MA6900
8 TONE 049656
27 28 29
8 TONE 049656
9 KEYBOARD 049696
30 31 32
MA6900
PARTS LIST K1 K2 K3 K4 K5 K6 K7 K8 K9 K10 K11 RLY REED FORM 1A 5V 500OHMS 08705000
K12 K13 K14 K15 K16 K17 K18 RLY REED FORM 1A 5V 500OHMS 08705000
Reference No. Description Part No. K19 RELAY POWER TV5 24V 08706900
LDR1 LDR2 LDR NETWORK VTL5C9 14417900
Interconnect Q1 Q2 Q3 Q4 TRANSISTOR N JFET 13222200
F1 FUSE 08910400 Q5 Q6 Q7 Q8 Q19 Q20 TRANSISTOR NPN 13225400
MT1 MT2 METER 12707700 Q9 Q10 Q11 Q12 Q13 Q14 TRANSISTOR PNP 120V 13225500
RT1 RT2 THERMISTOR 05200800 Q15 Q16 Q27 Q28 Q29 Q30 Q37 Q38 Q48 TRANSISTOR PNP 13222400
S1 SWITCH 14807300
T1 POWER TRANSFORMER 04967600 Q17 Q18 Q21 Q22 Q23 Q24 Q25 Q31 Q33 TRANSISTOR NPN 2K/REEL 13222300
T2 T3 OUTPUT TRANSFORMER 04967500 Q34 Q41 Q42 Q43 Q44 Q46 Q52 Q53 TRANSISTOR NPN 2K/REEL 13222300
TB1 TERMINAL BLOCK 07409100 Q35 Q36 TRANSISTOR PNP 2SA32IC 13228600
Q39 Q40 TRANSISTOR NPN 25C3334C 13228500
049654 MAIN PCB Q45 Q47 TRANS POWER N-CHN ENHANCE 13224200
C1 C2 C69 C70 C71 C72 C73 C74 C75 C76 CAP ELECT 10UF 16V 06638200 Q49 IC REGULATOR +5V 13310800
C3 C4 C9 C10 C11 C12 C47 C48 C49 CAP MONO 100PF 100V 10% 06130000 Q50 IC REGULATOR -15V 13315300
C5 C6 C93 C94 CAP ELECT 47UF 35V 06644600 Q51 IC REGULATOR 15V 13315400
C7 C8 CAP DISC .47UF 50V MONO 06124900 Q54 TRANS P CHAN JUNCTION FET 13222600
C13 C14 CAP POLY .15UF 10% 250V 06436300 R1 R2 R23 R24 R26 R61 R62 R91 R92 RES MF 10K 1% 1/4W 14405300
C15 C16 CAP POLY .047UF 10% 250V 06436400 R3 R4 R49 R50 R53 R54 R84 R171 RES MF 3.32K 1% 1/4W 14409500
C17 C18 CAP MPOLY .0068UF 5% 63VDC 06431000 R5 R6 R15 R16 RES MF 475 1% 1/4W 14408600
C19 C20 C21 C22 C23 C24 C27 C28 C31 CAP ELECT 10UF 100VDC 06646200 R7 R8 R93 R94 RES MF 10M 1% 1/4W 14426400
C25 C26 C29 C30 C38 C41 C42 C55 C56 CAP MONO .1UF 50V 20% Z5U 06130500 R9 R10 R11 R12 R113 R114 R170 RES MF 47.5K 1% 1/4W 14410800
C33 C34 C39 C40 C43 C44 C45 C46 C53 CAP ELECT 10UF 50V 06644500 R19 R20 R137 R141 R146 R147 R151 RES MF 1K 1% 1/4W 14409000
C35 C36 CAP ELECT 1UF 50V 06651000 R21 R22 R77 R78 R79 R80 R155 RES MF 100 1% 1/4W 14419600
C50 C51 C52 C59 C60 C91 C92 CAP MONO 100PF 100V 10% 06130000 R25 RES MF 165K 1% 1/4W 14411600
C54 C77 C78 C87 C88 CAP ELECT 10UF 50V 06644500 R27 RES MF 68.1K 1% 1/4W 14408100
C57 C58 C89 C90 CAP MONO 47PF 200V 10% 06129900 R29 R30 R63 64 R101 R102 RES MF 4.75K 1% 1/4W 14409700
C61 C62 CAP M POLY .033UF 5% 63VDC 06431800 R35 R36 R37 R38 RES MF 806 1% 1/4W 14408900
C63 C64 CAP M POLY .01UF 5% 63VDC 06431200 R39 R40 R59 R60 RES MF 187K 1% 1/4W 14440600
C65 C66 C118 C119 CAP ELECT 220UF 25V 06650700 R41 R42 R43 R44 R45 R46 R47 R48 R132 RES MF 221 1% 1/4W 14417200
C67 C68 C95 C96 C97 C98 C99 C103 CAP MONO .1UF 50V 20% 06130500 R51 R52 R55 R56 R57 R58 R65 R66 RES MF 324 OHM 1% 1/4W 14433800
C79 C80 C81 C82 C83 C84 C85 C86 CAP ELECT 10UF 16V 06638200 R67 R68 RES 1.8 OHM 2W 5% WW FP 13923000
C100 C101 C102 CAP MONO 220PF 100V 10% 06130100 R69 R70 RES WW 2.7 OHM 2W 5% FP 13921800
C104 C105 C107 C110 C114 CAP MONO .1UF 50V 20% Z5U 06130500 R71 R72 RES MF 27.4K 1% 1/4W 14414100
C106 CAP ELECT 470UF 50V 06646900 R73 R74 R75 R76 RES FP 47 OHM 5% 1/4W 13704200
C108 C113 CAP ELECT 1000UF 25V 06651300 R81 R83 R166 R167 RES MF 12.1K 1% 1/4W 14415400
C109 C112 C116 CAP ELECT 3300UF 35V 06650900 R82 R87 RES MF 2.1K 1% 1/4W 14429900
C111 C115 CAP ELECT 100UF 25V 06644700 R85 RES MF 20K 1% 1/4W 14410400
C117 CAP M POLY .1UF 10% 100VDC 06425400 R86 R89 R90 R111 R129 R145 RES MF 100K 1% 1/4W 14411300
D1 D2 D3 D4 D5 D6 D7 D8 D11 D12 DIODE SILICON 07004700 R95 R96 RES MF 274K 1% 1/4W 14444100
D9 D10 DIODE ZENER 16V 5% 500MW 07011400 R97 R98 POT TRIM 100K OHM 13450200
D13 D14 D15 D16 D17 D18 D19 D20 DIODE RECTIFIER 07013100 R99 R100 RES MF 2.21M 1/4W 14426500
D21 D23 D24 DIODE SILICON 07004700 R103 R104 R105 R106 RES MF 11K 1% 1/4W 14410100
D22 DIODE ZENER 8.2V 1/2W 07013000 R107 R108 R109 R110 RES MF 5.62K OHM 1% 1/4W 14444700
F1 FUSE 2A SLO-BLO 5X20 08908900 R112 R125 R126 R127 R128 R130 R131 RES NETWORK 2X220K ISO 14426200
F1 F2 F3 HLDR FUSE 5X20MM PCB MNT 17815900 R115 R116 RES MF 47.5 1% 1/4W 14444200
F2 F3 FUSE 5X20 1.6A IEC SLO-BLO 08909600 R117 R118 RES MF 95.3K 1% 1/4W 14412700
IC1 IC NAND 2 INPUT X 4 13316100 R119 R120 R172 RES MF 7.5K 1% 1/4W 14421000
IC2 IC3 IC16 IC OPERATIONAL AMPLIFIER 13302800 R121 R122 RES MF 95.3 1% 1/4W 14422000
IC4 IC5 IC OPRTINL AMP LOW NOISE 13306700 R123 R124 RES MF 2.21 OHM 1/4W 1% 14437800
IC6 IC7 IC17 IC DUAL OPERATIONAL AMP 13326000 R13 R14 R17 R18 R31 R32 R33 R34 RES MF 267K 1% 1/4W 14411800
IC8 IC10 IC12 IC SHFT REG SER-PAR 13318600 R133 R134 R135 R138 R139 RES MF 221 1% 1/4W 14417200
IC9 IC OCTAL DAR TRNS ARRY 13336000 R136 R140 RES NET 2 X 22K ISOLATED 14436600
IC11 IC13 IC 8 LN DRIVER ARRAY 13318000 R142 R143 RES MF 30.1K 1% 1/4W 14422500
IC14 IC15 IC AND 2 INPUT X 4 13317500 R144 R148 RES NETWORK 2X220K ISO 14426200
J1 J2 CONN MALE 7 PIN 11721700 R149 R150 RES MF 22.1 1% 1/4W 14416000
J3 J4 J6 CONN 4 PIN 11721500 R152 R153 RES MF 1K 1% 1/4W 14409000
J5 CONN 23PIN FFC 11771500 R154 RES NETWORK 8X100 ISO 14427500
J7 CONN MALE 3 POS MTS100 NRML 11721400 R156 R157 R158 R159 R160 R161 R162 RES MF 182 1/4W 1% 14427300
J8 CONN 8 POS MALE FRCTION LK 11727500 R163 RES MF 182 1/4W 1% 14427300
J9 J10 J11 J12 J13 BLADE FASTON W/FEET 11770800 R164 R165 RES MF 178K 1% 1/4W 14442000
J14 J15 RECEPTACLE XLR FEMALE 11768500 R168 RES MF 3.65K 1% 1/4W 14418900
J16 J17 J18 RCA JACK 3X2 WHT/RED 14MM 11779000 R169 RES MF 3.16K 1% 1/4W 14419900
J19 J20 J21 J22 J23 J24 JACK HDPHNE DUAL BLACK 1/8 11754900 R173 RES MF 5.11K 1% 1/4W 14408300
J25 CONN GOLD F RIGHT ANGLE 11766100 S1 SWITCH SLIDE 14805900
J26 J27 CONN MALE 5 PIN 0.1 POST 11721600 SP1 SP2 BRACKET PCB CARD MOUNTING 00361100
33 34
PARTS LIST con't R14 R15
R19
RES MF 1K 1% 1/4W
RES MF 2.21 OHM 1/4W 1%
14409000
14437800
Y1 RESONATOR CERAMIC 6.0MHZ W/CAP 18003900
Reference No. Description Part No.
049235 LAMP PCB
DS1 DS2 DS3 LAMP 14V #7373 05812000
J1 4 PIN RT. ANGLE 11724000
049665 HEATSINK PCB J2 CONN. 2 POS. R-ANGLE 11727400
C1 C2 CAP ELECT 47UF 35V 06644600
C3 C5 CAP MONO .1UF 50V 20% Z5U 06130500 049656 TONE PCB
C7 C8 CAP MONO 100PF 100V 10% NPO 06130000 C1 C2 CAP M POLY .1UF 10% 100VDC 06425400
C9 C16 CAP MONO .01UF 50V 20% X7R 06130400 C3 C4 CAP ELECT 10UF 16V (4X5 CASE) 06638200
C10 CAP POLYPROP 0.15UF 10% 250VDC 06436300 C5 C6 CAP MONO 220PF 100V 10% NPO 06130100
D1 D2 D3 D4 D5 DIODE SILICON 07004700 C7 C8 CAP MONO 47PF 200V 10% NPO 06129900
D6 D7 DIODE 200V 6A 07013300 C9 C10 CAP MONO 22PF 200V 10% NPO 06129800
J1- CONN MALE 7 PIN 11721700 C11 C12 CAP ELECT 220UF 25V 06650700
J2- CONN HEADER 2 PIN 0.156 11740400 C13 C14 C33 C34 CAP ELECT 47UF 50V 06621500
J4 BLADE FASTON W/FEET 11770800 C15 C16 C43 C44 C45 C46 C54 CAP ELECT 10UF 50V 06644500
J4- CONN MALE 2 PIN 11721300 C17 C18 CAP M POLY .047UF 5% 63VDC 06432000
Q1 TRANSISTOR NPN SILICON 13217100 C19 C20 CAP ELECT 1.5UF 10% 50V 06627100
Q2 TRANSISTOR PNP SILICON 13217200 C21 C22 CAP M POLY .01UF 5% 63VDC 06431200
Q6 TRANSISTOR NPN 13226200 C23 C24 CAP M POLY .47UF 5% 50/63VDC 06433300
Q7 TRANSISTOR PNP 13226100 C25 C26 CAP MPOLY .0033UF 5% 63VDC 06430600
R1 R8 RES MF 221 1% 1/4W 14417200 C27 C28 CAP M POLY .15UF 5% 63VDC 06432700
R2 R9 RES MET OX 680 5% .5W 13709300 C29 C30 CAP POLY 0.001MF 5% 63VDC 06430000
R3 R10 RES MF 15K 1% 1/4W 14441200 C31 C32 CAP M POLY .033UF 5% 63VDC 06431800
R6 R11 RES MET OX 1.8K 5% .5W 13709400 C35 C36 C37 C38 CAP M POLY .22UF 5% 63VDC 06432900
R7 RES MET OX 430 5% .5W 13709500 C39 C40 C41 C42 CAP MONO 470PF 100V 10% NPO 06130200
R12 RES MET OX 47 5% .5W 13709600 C47 C48 C49 C50 C51 C52 CAP MONO .1UF 50V 20% Z5U 06130500
R13 POT TRIM 200 OHM 20% HORIZ AD 13439000 C53 CAP ELECT 47UF 10V BP 06637800
R30 RES MF 2.21 OHM 1/4W 1% 14437800 D1 D2 DIODE SILICON 07004700
R31 R32 R33 R36 R37 R38 RES WW .5 OHM 5W 5% 13917700 IC1 IC6 IC7 IC DUAL OPERATIONAL AMPLIFIER 13326000
RT1 SENSOR THERMAL 14424900 IC2 IC3 IC4 IC5 IC OPERATIONAL AMPLIFIER 13302800
J1 CONN 8 POS MALE FRICTION LOCK 11727500
049653 CAPACITOR PCB J2 CONN 4 PIN 11721500
C1 C2 CAP ELECT 25000UF 75V 06650400 J3 CONN MALE 6 POS RT ANGLE 11770700
C3 CAP M POLY .22UF 20% 400VDC 06426700 K1 K2 K3 RELAY REED FORM 1A 5V 500 OHMS 08705000
D1 D2 DIODE SILICON 07004700 R1 POT 50KAX2 13449000
D3 DIODE BRIDGE RECTIFIER 07013900 R2 POT BALANCE 2KOHM 13446400
J1 CONN MALE 3 POS MTS100 NORMAL 11721400 R3 R4 R5 R6 R7 POT EQUAL 13445700
J2 J3 CONN HEADER 2 PIN 0.156 11740400 R9 R10 RES MF 2.21K 1% 1/4W 14429800
J4 J5 J6 J7 J8 J9 BLADE FASTON W/FEET 11770800 R11 R12 RES MF 3.32K 1% 1/4W 14409500
K1 K2 RELAY 24V TV8/VDE CERTIFIED 08707200 R13 R14 RES MF 475K 1% 1/4W 14436400
R15 R16 R19 R20 RES MF 1K 1% 1/4W 14409000
049655 CONTROL PCB R17 R18 RES MF 10K 1% 1/4W 14405300
C3 C5 C6 C7 C10 CAP MONO .1UF 50V 20% Z5U 06130500 R21 R22 R45 R46 RES MF 2.74K 1% 1/4W 14430400
C4 CAP ELECT 220UF 25V 06650700 R23 R24 R27 R28 R31 R32 R35 R36 RES MF 681 1% 1/4W 14419500
C8 C9 CAP MONO 220PF 100V 10% NPO 06130100 R25 R26R29 R30 R33 R34 R37 R38 R43 RES MF 100K 1% 1/4W 14411300
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 LED LAMP RED 07009300 R39 R40 RES MF 475 1% 1/4W 14408600
DS10 DS11 DS12 LED LAMP RED 07009300 R41 R42 RES MF 40.2K 1% 1/4W 14410700
DS13 DS14 LED AMBER 05813300 R44 R51 R52 RES MF 100K 1% 1/4W 14411300
DS15 DS16 DS17 DS18 DS19 DS20 LAMP INCANDESCENT 14V 100MA 05815300 R47 R48 RES MF 33.2K 1% 1/4W 14401500
DS21 DS23 LAMP INCANDESCENT 14V 100MA 05815300 R49 R50 RES MF 22.1 1% 1/4W 14416000
IC1 IC AND 2 INPUT X 4 13317500 R53 R54 RES MF 100 1% 1/4W 14419600
IC2 IC DC MOTOR DRIVER 13319100 R55 R56 R57 R58 RES MF 10 1% 1/4W 14415700
IC3 IC4 IC SHFT REG SER-PAR 13318600
IC5 IC PROGRAMMED 13343800 049696 KEYBOARD PCB
IC5 SOCKET IC 24-PIN 17813900 C1 CAP MONO .1UF 50V 20% Z5U 06130500
IC6 IC MICRO RESET POS 13324100 C2 CAP ELECT 47UF 35V 06644600
J1 CONN 23PIN FFC 11771500 J3 JACK PHONO 1/8 STEREO VER 11746200
J6 CONN 12 PIN FFC 11772000 J4 CONN 4 PIN 11721500
J7 J8 CONN 4 PIN 11721500 J5 CONN 12 PIN FFC 11772000
R2 RES MF 100K 1% 1/4W 14411300 MT1 GASKET SENSOR 09437700
R3 RES MF 75 OHM 1% 1/4W 14444400 MT1 RECEIVER IR 12104100
R4 RES MF 10 1% 1/4W 14415700 R1 RES MF 100 1% 1/4W 14419600
R5 R16 RES MF 10K 1% 1/4W 14405300 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 SWITCH TACT 15005800
R6 RES NETWORK 3X10K BUSSED 14429000
R7 R8 R9 R10 R11 R12 R13 R20 R21 RES MF 324 OHM 1% 1/4W 14433800
35 36
MA6900
EXPLODED VIEW
37 38
EXPLODED VIEW EXPLODED PARTS LIST
Item Part
No. No. Description
1 016456 GLASS 50 018691 HEATSINK
2 148073 INPUT POWER SWITCH 51 084194 ISOSTRATE
3 017531 PUSHBUTTON ASSY RED 52 112087 SPACER PCB 1/4
4 017517 PUSHBUTTON ASSY BLK 53 749665 HEATSINK PCB ASSY
5 078033 O-RING 54 414118 CLIP TRANSISTOR 218
6 749695 KNOB ASSY 55 414119 CLIP TRANSISTOR 214
7 104017 WASHER FELT BLK 3/4 X 1/4 X 1/16 56 401059 SCREW SM 6 X 5/8 PH PAN TYPE A
8 749694 KNOB ASSY 57 005188 SUBREAR PANEL
9 104073 WASHER FELT 1/4 X 5/8 MPI-4 58 749653 CAPACITOR PCB ASSY
10 017854 BEZEL HEADPHONE 59 412060 SPACER #4 X 5/16 STEEL
11 018707 BOTTOM EXTRUSION 60 401078 SCREW TAP 8-32 X 5/16 PH PAN
12 400149 SCREW MACH 6-32 X 1/4 FL U/H ST 61 402003 NUT MACH 6-32 W/LOCK
13 018738 TOP EXTRUSION 62 005202 STRAP
14 094016 TAPE FOAM 1/4 X 1/8 63 005185 TOP COVER
15 004899 BRACKET EXTRUSION 64 084135 THERMAL PAD
16 018612 ENDCAP 7" 65 094401 TAPE FOAM 1/4 X 1 3M #4504
17 401042 SCREW TS 4-40 X 1/2 SLOT FILLISTER 66 078034 GROMMET
18 094360 TAPE FOAM 1/2 X 1/2 67 005453 REAR PANEL
19 401172 SCREW TC 6-32 X 1/4 PH FL U/C 68 004800 PLATE OUTPUT
20 017363 PLEXIGLAS FILTER LT BLUE 69 084189 BINDING POST DUAL RED-RED
21 094017 TAPE FOAM 1/4 X 1/4 70 084124 BINDING POST DUAL
22 017864 PLEXI MA6900 71 104148 WASHER FLAT BRASS
23 022314 FISHPAPER SHIELD 72 104130 WASHER LOCK #10 SLIT PHOS/BRNZ
24 749696 KEYBOARD PCB ASSY 73 110009 NUT M5 X 0.8 BRASS W/GOLD PLATE
25 005475 SUBPANEL 74 750156 MAIN PCB ASSY
26 410004 NUT CONTROL M7 X 0.75 HEX 75 404142 WASHER LOCK 2.5mm INT STAR ZINC
27 404013 WASHER LOCK 5/16 X .435 X .002 76 101197 SCREW HI/LO 4-24 X 3/8 PH RD BLK
28 410002 NUT 5 CONTROL M9 X 0.75 77 102006 NUT MACH 10-32 W/LOCK
29 404014 WASHER LOCK 3/8 X .507 X .002 INT STAR 78 078025 GROMMET RUBBER 3/4
30 077032 SLEEVING FIBERGLASS 7/16 79 074091 TERMINAL BLOCK AC
31 401054 SCREW TAPTITE 6-32 X 1/4 PH PAN BLK 80 404001 WASHER FLAT STEEL 4 X 9/32 X .025
32 750510 CONTROL PCB ASSY 81 404004 WASHER LOCK 5 X .255 INT STAR
33 021165 SPACER 4 X 1/4 82 402022 NUT MACH 4-40 X 3/16 X 1/16
34 402001 KEP NUT 4-40 CADMIUM PLATE 83 005194 BRACKET CHASSIS SUPPORT
35 749656 TONE PCB ASSY 84 400256 SEMS MS 4-40 X 3/8 CCA PAN
36 124092 METER 85 117487 RECEPTACLE AC LINE
37 092342 FILTER PALE BLUE 86 178161 HOLDER FUSE 5 X 20mm IEC
38 017447 LIGHT BOX PLASTIC 87 084217 GROUND POST GOLD
39 749235 LAMP PCB ASSY 88 005401 HEATSINK VENT
40 114072 RIVET NYLON POP-IN 89 401250 SCREW TT 6-32 X 1/2 PH PAN
41 005714 DUST COVER 90 017869 SHIELD
42 126819 TOP COVER DECAL 91 094332 TAPE MTG DBL COATED 1/8 THK
43 400287 SCREW MACH 8-32 X 3/8 PH TRUSS HD 92 005634 BOTTOM COVER
44 400250 SCREW MACH SEMS 6-32 X 1/4 PH PAN 93 404072 CORD DIAL .027
45 005702 CHASSIS 94 017218 FOOT BLACK PLASTIC
46 749675 OUTPUT TRANSFORMER 95 404080 WASHER FLAT #10 CLEAR ZINC
47 749676 POWER TRANSFORMER 96 400159 SCREW MACH 10-32 X 3/4 PH PAN
48 166128 DECAL OUTPUT TRANSFORMER 97 402020 NUT MACH 6-32 SELF LOCK
49 166129 DECAL POWER TRANSFORMER 98 104072 WASHER 1/4 IDX .408 X .18
99 104078 WASHER LOCK #8 STAR
100 410014 NUT 4 X .7
101 101222 SCREW TT SEMS 6-32 X 1/4
39 40
MA6900
REPACKING INSTRUCTIONS
41
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 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 040809
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