McIntosh MR85 User manual

SERVICE MANUAL
Performance Specifications ........................................ 2
Notes ......................................................................... 2
Rear Panel .................................................................. 3
Section Location ........................................................ 3
Block Diagram ........................................................... 4
Interconnection Diagram ...................................... 5 - 6
Power Supply Schematic and PCB ...................... 7 - 10
Display Schematic and PCB .............................. 11 - 16
Tuner Schematic and PCB ................................. 17 - 19
RAA1 Schematic and PCB........................................ 20
Parts List ............................................................ 21 - 22
Exploded View and Parts List ............................. 24 - 26
Repacking Instructions ............................................. 27
CONTENTS
INCLUDING TM1 TUNER MODULE OPTION
AM/FM TUNER

PERFORMANCE SPECIFICATIONS
2
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
c. Others - Pin 1
5. WARNING
Parts marked with the symbol have critical
characteristics. Use only replacement parts recom-
mended by the manufacturer.
FM Tuner Specifications
Useable Sensitivity
14dBF which is 1.4uV across 75 ohms
50dB Quieting Sensitivity
Mono: 19dBF which is 2.4uV across 75 ohms
Stereo: 35dBF which is 15uV across 75 ohms
Signal To Noise Ratio
Mono: 75dB
Stereo: 70dB
Frequency Response
Mono: + 0, - 1dB from 20 to 15,000Hz
Stereo: + 0, - 1dB from 20 to 15,000Hz
Harmonic Distortion
Mono: 0.3% at 100Hz
0.3% at 1,000Hz
0.3% at 10,000Hz
Stereo: 0.45% at 100Hz
0.45% at 1,000Hz
0.65% at 10,000Hz
IntermodulationDistortion
Mono 0.25%
Stereo0.45%
Capture Ratio
1.2dB
Alternate Channel Selectivity
75dB
Spurious Response
100dB
Image Response
75dB
RF Intermodulation
65dB
Stereo Separation
45dB at 100Hz
45dB at 1,000Hz
35dB at 10,000Hz
SCA Rejection
65dB
AM Tuner Specifications
Sensitivity
20uV External Antenna Input
Signal To Noise Ratio
48dB at 30% modulation
58dB at 100% modulation
Harmonic Distortion
0.5% maximum at 50% modulation
Frequency Response
50Hz to 6kHz NRSC
Adjacent Channel Selectivity
45dB minimum IHF
Image Rejection
65dB minimum from 540 to 1600kHz
IF Rejection
80dB minimum
General Specifications
Rated Output
Fixed output: 1.2 Volts
Variable output: 0 - 1.2 Volts
OutputImpedance
Less than 100 ohms
Power Requirements
100 Volts, 50/60Hz at 20 watts
110 Volts, 50/60Hz at 20 watts
120 Volts, 50/60Hz at 20 watts
220 Volts, 50/60Hz at 20 watts
230 Volts, 50/60Hz at 20 watts
240 Volts, 50/60Hz at 20 watts
Note: Refer to the rear panel of the MR85 for the correct voltage.
Dimensions
17-1/2” (44.5cm) W, 5-3/8” (13.7cm) H, 17-1/2” (44.5cm) D,
(including clearance for connectors)
Weight
25.5 pounds (11.6 kg) net, 43 pounds (19.5 kg) in
shipping carton

REAR PANEL
MR85
SECTION LOCATION
3
TOP VIEW WITH COVER REMOVED

BLOCK DIAGRAM
4

56
MR85
INTERCONNECT

78
2
POWER SUPPLY 049410

910
2
POWER SUPPLY 049410
MR85

11 12
3
DISPLAY 049409 1 0F 2

13 14
3
MR85
DISPLAY 049409 2 0F 2

3
15 16
DISPLAY 049409

17 18
4A
MR85
TUNER 049084
4B

19 20
4A
TUNER 049084
4B 5A
RAA1 049084
5B

PARTS LIST
PART NO DESCRIPTION REF NO
INTERCONNECT
171320 SWITCH CABLE ASSY
117711 AC INPUT LINE FILTER EM1
089101 FUSE, 250mA SLO-BLO 5 X 20 F1
159327 MR85 POWER TRANSFORMER T1
074091 AC TERMINAL BLOCK TB1
049410 POWER SUPPLY PCB
003611 CARD MOUNTING BRACKET BRKT1
BRKT2
061268 MONO CAP .1UF, 50V, Z5U C1 C2 C3
061273 220PF 5% 100V NPO C8
061277 MONO CAP 0.1MF 20% 50V C4 C5 C6 C7
064307 CAP M POLY .0039UF 5% 100/250VDC C21 C22
064312 CAP M POLY .01UF 5% 63VDC C19 C23 C24
064314 CAP M POLY .015UF 5% 63/250VDC C20
064316 CAP M POLY .022UF 5% 63VDC C18
064338 CAP M POLY 0.1MF 100V C16 C17
066161 CAP ELECT 100UF 25V-50V C10 C11 C12
066214 CAP ELECT 22UF 100V RADIAL C13
066215 CAP ELECT 47UF 50V C42
066221 CAP ELECT 10UF 50V SINGLE END C35 C36 C37
066278 CAP ELECT 47MF 100V 20% C32
066344 CAP ELECT 100UF 25V C41
066360 CAP ELECT 3300UF 35V C9
066404 CAP ELECT 1000MF 16V C15
066443 CAP ELECT 4700MF 35V C14
066469 CAP ELECT 470UF 50V C33 C34
066506 CAP ELECT 22UF 100V C46 C48 C49
C50 C51 C52
066510 CAP ELECT 1UF 50V C40
070047 SILICON DIODE 1N4148 T&R D12 D15 D16
D17 D18 D19
D20 D25
070085 DIODE ZENER 6.2V 5% 500MW D11
070121 DIODE ZENER 33V 5% 1/2W D3
070131 DIODE RECTIFIER D1 D2 D4 D5
D7 D8 D9 D10
D13 D14
070132 DIODE ZENER 5V D6
080017 TO-220 HEATSINK IC11
087050 REED RELAY FORM 1A, 5V, 500 OHMS K3 K4 K5 K6
087057 RELAY K1 K2
089088 FUSE 2A SLO-BLO 5 X 20 250VIEC F3
117215 4-PIN CONNECTOR J2- J9-
117217 MALE CONN: 7 PIN J1- J10-
117218 MALE CONN 6-POS FRICTION LK J3- J4- J5- J6-
J7- J8-
117450 PHONE JACK 4P RCA GOLD PLATED J20 J21
117549 HEADPHONE JACK DUAL BLACK 1/8 J22 J23
117708 FASTON BLADE W/FEET J11 J12 J13
J14 J15 J16
J17 J18 J19
132090 TRANSISTOR NPN DAR MPSA25 Q1
132223 TRANSISTOR NPN MPS4124 2K/REEL Q2 Q3
133114 IC AUDIO PROCESSOR U3
133119 IC REGULATOR +12 VOLT IC11
133175 IC AND 2 INPUT X 4 IC2 IC3 IC6
133186 IC SHFT REG SER-PAR IC1
133192 IC NAND SCHMIT 2-IN X 4 IC7
133306 NEG 24V REGULATOR IC10
133342 IC QUAD ANALOG SWITCH HI SPEED IC4 IC5
133365 IC 5V 1.5A REGULATOR LOW DROP IC12
134495 POTENTIOMETER DUAL 20K TAPPED R54 R55
137002 RES FP 1.1 OHM 1/4W 5% R18
137025 FLAMEPROOF RES: 10 OHMS 5% 1/4W R13
139005 WIRE RES: 2 OHMS 10% 5W R52
144053 RES MF 10K 1% 1/4W R16 R22 R27
R28 R30
144090 RES MF 1K 1% 1/4W R5 R24 R50
144097 RES MF 4.75K 1% 1/4W R10 R51
144101 RES MF 11K 1% 1/4W R11
144103 RES 16.5K 1% 1/4W R29 R31
144112 RES MF 82.5K 1% R12
144113 RES MF 100K 1% 1/4W R2 R3 R9 R41
144154 RES MF 12.1K 1% 1/4W R26
144157 RES MF 10 1% 1/4W R1
144172 RES MF 221 1% 1/4W R4 R8
144181 RES MF 18.2K 1% 1/4W R25
144187 RES MF 22.1K 1% 1/4W R15 R23 R49
144191 RES MF 1.21K 1% 1/4W R14
141196 RES CF 100 5% 1/4W R17 R20 R33
R35
144262 RES NETWORK 2X220K ISO R57 R60
144273 RES MF 182 1/4W 1% R6 R7
144323 RESNET 3 X 220K OHM BUSSED R53
144364 RES MF 475K 1% 1/4W R40
144366 RES NETWORK ISOLATED 2X22K R56 R58 R59
R61
144442 RES MF 47.5 1% 1/4W R19 R21 R34
R36
049409 DISPLAY PCB
058109 LED, SQUARE TYPE(RED) DS4 DS5
058150 MX132 12 CHARACTER DISPLAY DS1
058153 INCANDESCENT LAMP 14V 100MA LAMP1 LAMP2
LAMP3 LAMP4
LAMP5 LAMP6
LAMP7 LAMP8
058155 PHOTO MICROSENSOR DETECT1
DETECT2
061262 MON CER 0.001MF 100V NPO C4 C5 C6 C8
C10 C11 C12
C13 C23 C40
061268 MONO CAP: .1UF,50V,Z5U C33 C34 C35
C36 C38
061277 MONO CAP 0.1MF 20% 50V C1 C2 C3
061285 MONO CAP 33PF C45 C46
064320 CAP M POLY .047UF 5% 63/100VDC C41
064325 CAP M POLY .1UF 5% 63VDC C42
064333 CAP M POLY .47UF 5% 50/63VDC C43
066215 CAP ELECT 47UF 50V C27 C28 C32
066221 CAP ELECT 10UF 50V SINGLE END C29 C30 C31
070047 SILICON DIODE 1N4148 T&R D6 D7
070061 ZENER DIODE:15V,1W D4
070093 LED LAMP RED DS2 DS3 DS6
DS7 DS8
117218 MALE CONN 6-POS FRICTION LK J1- J2- J3- J4-
132223 TRANSISTOR NPN MPS4124 2K/REEL Q2
132224 TRANSISTOR PNP Q1
133186 IC SHFT REG SER-PAR IC6
133192 IC NAND SCHMIT 2-IN X 4 IC4
133249 IC CMOS EPROM IC2
133347 VF ALPHANUMERIC CONTROLLER IC5
133366 IC 8 BIT A/D SERIAL OUTPUT IC3
133408 PROGRAMMED MICRO MR85 V1.00 IC14
137042 FLAMEPROOF RES 47 OHM 5% 1/4W R12
144053 RES MF 10K 1% 1/4W R6 R9 R10
144090 RES MF 1K 1% 1/4W R2 R42
144108 RES MF 47.5K 1% 1/4W R19
144113 RES MF 100K 1% 1/4W R25
144157 RES MF 10 1% 1/4W R11 R16 R24
144172 FF RES 221 1% R8
144187 RES MF 22.1K 1% 1/4W R20 R26 R28
144196 RES MF 100 1% 1/4W R7
144250 RES NETWORK 9 X 47K BUS R14 R21 R23
144253 RES NET 10K X8 RES B R5
144254 RES NETWORK 5X47K BUSSED R22
144259 RES NETWORK 4 X 100 ISO R45
144263 RES NETWORK 8X330 ISO R30
144280 RES NETWORK 9X1K ISO R1 R3 R4
144298 RES MF 2.21K 1% 1/4W R27
21
MR85

22
144351 1.74K 1% 1/4W MF RES R17
144366 RES NETWORK ISOLATED 2X22K R31
150058 TACT SWITCH S1 S2 S3 S4
S5 S6 S7 S8
S9 S10
178133 40-PIN IC SOCKET IC14
180051 CRYSTAL 11.0592MHZ Y1
049084 TUNER/RAA1 PCB
060027 TRIM CAP: 2-10PF C59 C60 C62
C63
060029 3-27PF TRIMMER CAPACITOR C61 C64 C65
C106
061002 DISC CAP: 1.8PF+/-.25PF NPO C35
061249 DISC CAP: .47UF 50V MONOLITHIC C50 C70 C71
C72
061256 M.CAP: 470PF,5%,100V C39
061257 360PF 5% 100V C21
061273 220PF 5% 100V NPO C76 C77 C78
C79
061275 MONO CAP: 100PF,5%,100V,NPO C2 C6 C12
C14 C17
061277 MONO CAP 0.1MF 20% 50V C1 C4 C7 C11
C19 C20 C26
C27 C29 C30
C34 C102
C104 C105
061282 22PF 10% 100V CAPACITOR C8 C24
061286 MONO CAP .047UF 10% 50V RADIA C10 C13 C15
C16 C18 C28
C33 C75
061287 MONO CAP .0022UF 10% 50V RADI C5 C23 C25
C31 C74 C103
061288 MONO CAP 10PF 10% 100V C3 C9 C22
C32
064310 M POLY CAP:.0068MF,10%,63V DC C82 C83
064314 M POLY CAP:.015UF,5%,63V DC C36 C40
064316 M POLY CAP:.022UF,5%,63V DC C80 C81
064318 M POLY CAP:.033UF,5%,63V DC C37 C41 C42
C43
064320 M POLY CAP:.047UF 5% 63VDC C38
064329 M POLY CAP 0.22UF 5% C73
066269 CAP ELECT 1UF 10% 50V C57 C58
066445 ELECT CAP 10MF, 50V AMMO PACK C45 C46 C47
C48 C49 C51
C52 C54 C55
066446 ELECT CAP 47MF, 35V AMMO PACK C53
066447 ELECT CAP 100MF 16V AMMO PACK C56 C67 C68
C69
070047 SILICON DIODE 1N4148 T&R D10 D102
D103 D104
070122 (8) DIODE TUNING ALL 8 DIODES USED
ON JAPANESE VERSION D1 D2 D3 D4
(D5 D6 D7 D8)
070125 TUNING DIODE D11 D12 D101
117213 2-PIN MALE CONNECTOR J6
117223 MALE CONN: 6 PIN RT. ANGLE J3
117240 4 PIN RT. ANGLE J5
117319 CONN, RT.ANGLE, MALE, 7 POS J4
117383 DIN CONN 7-PIN J2
117661 GOLD F CONNECTOR RIGHT ANGLE J1
117677 HEADER 5 PIN J101-
122229 RF CHOKE: 3.3UH, 10% L1
122249 ANT. COIL L4 L5
122250 MIXER COIL L2 L3
132178 TRANSISTOR: RF FET, J-310 FET Q102
132220 TRANSISTOR: 1-4V,PNC OFF 250 OH Q8 Q101
132223 TRANSISTOR NPN MPS4124 2K/REEL Q3 Q5 Q6 Q7
Q10 Q11 Q12
132224 TRANSISTOR PNP SI MPS4126 2K/R Q2 Q9
132256 #3SK114Y (Q1) D MOS FET Q1
133147 MC78L08ACP +8V REG IC6
133189 IC OPERATIONAL AMPLIFIER IC4 IC5
133231 LA1175 FM FRONT END IC1
133270 IC DIRECT PLL FREQ SYNTHESIZER IC3
133381 AM-FM MPX TUNER IC IC2
134406 TRIMPOT 22K R70
134414 POTENTIOMETER: 10K OHM R71 R73
141025 RES CF 100 5% 1/4W R4 R14 R21
R60
141033 RES CF 220 5% 1/4W R54 R65
141037 RES CF 330 5% 1/4W R23 R26
141041 RES CF 470 5% 1/4W R103
141049 RES CF 1.0K 5% 1/4W R3 R5 R7 R30
R38
141057 RES CF 2.2K 5% 1/4W R39 R46
141060 RES CF 3.3K 5% 1/4W R63
141064 RES CF 4.7K 5% 1/4W R22 R24 R33
R35 R69
141072 RES CF 10K 5% 1/4W R1 R11 R15
R19 R29 R41
R44 R50 R64
R68 R75 R101
R102 R105
141076 RES CF 15K 5% 1/4W R6 R20 R40
141080 RES CF 22K 5% 1/4W R17 R52 R55
R58
141088 RES CF 47K 5% 1/4W R8 R9 R13
R18
141096 RES CF 100K 5% 1/4W R56 R61 R76
141116 RES CF 680K 5% 1/4W R27 R28
141124 RES CF 2.2M 5% 1/4W R16 R42
141144 RES CF 22 5% 1/4W R67 R104
141152 RES CF 47 5% 1/4W R51 R74
144097 METAL FILM RES: 4.75K 1% 1/4W R32 R43 R45
R53
144121 METAL FILM RES: 2.67K 1% 1/4W R47 R48
144142 METAL FILM RES 2.87K 1% 1/4W R10 R25
162102 TRANSFORMER: QUAD DET PRIM T9
162103 TRANSFORMER: QUAD DET SEC T8
162113 TRANSFORMER (MATCHING) T7
162114 10.7MHZ MIXER TRANSFORMER T10
162115 AM OSC. COIL T11 T101
162117 AM RF TRANSFORMER T12
180036 CRYSTAL 7.2MHZ Y1
180046 CERAMIC RESONATOR 450KHZ Y2
180055 FILTER 450KHZ FN6
180056 FILTER CERAMIC 10.7MHZ FN1 FN2 FN3
049106 SWITCH PCB
117670 CONNECTOR 3-PIN RIGHT ANGLE J1-
146249 SWITCH PULSE ROTARY S1
PARTS LIST

23
NOTES
MR85

EXPLODED VIEW PARTS LIST
24
1 016419 FRONT GLASS
2 171320 C/A SWITCH
3 017531 PUSHBUTTON ASSY RED
4 017517 PUSHBUTTON ASSY
5 078033 O-RING
6 049411 KNOB ASSY
7 104073 BLK FELT WASHER
8 018611 5” ENDCAP
9 101042 TS 4-40 X 1/2 SLOT FILLISTER
10 094360 FOAM TAPE 1/2 X1/2
11 004810 EXTRUSION BRACKET 5”
12 018609 BOTTOM EXTRUSION
13 101172 TCS 6-32 X 1/4 PHIL FLAT U/C
14 100147 MS 6-32 X 3/16 PHIL FLAT U/C
15 018587 TOP EXTRUSION
16 022314 LED SHIELD
17 017806 PLEXIGLAS LOWER
18 017805 PLEXIGLAS UPPER
19 017738 FRONT PANEL FILTER
21 017737 VINYL LOCATOR
22 049409 DISPLAY PCB ASSY
23 100275 MS 6-32 X 1/2 PHIL BLK TRUSS HD
24 078031 GROMMET
25 021030 SPACER: 6 X 1/4
26 110004 M7 X .75 HEX CONTROL NUT
27 104013 LK WASH: 5/16 X .435 X .002 INT STAR
28 049106 SWITCH PCB ASSY
29 021063 STANDOFF: 6-32 X 1-1/8 HEX
30 005077 SUBPANEL
31 104007 LK WASH: 6 X .288 INT STAR
32 100157 MS 6-32 X 1/4 PHIL PAN ZINC
33 005072 TRANSFORMER CAN
34 101054 TS 6-32 X 1/4 PHIL PAN TAPTITE BLK
35 102045 KEP-NUT 6-32 SPECIAL
36 078017 GROMMET 3/4 X 9/16
37 074091 AC TERMINAL BLOCK
38 104001 FLAT STEEL WASH #4 X 9/32 X .025
39 104004 LK WASH: 5 X .255 INT STAR
40 102022 MN 4-40 3/16 X 1/16
41 005073 CHASSIS TRAY
42 178160 FUSE HOLDER
43 100284 SEMS 2-56 X 1/4 PHIL PAN
44 004943 RIGHT SIDE PANEL
45 004942 LEFT SIDE PANEL
46 004940 TOP COVER
47 101078 TS 8-32 X 5/16 PHIL PAN BLK
48 004860 BOTTOM COVER
49 017218 PLASTIC FEET-BLACK
50 104080 FLAT WASHER #10 CLEAR ZINC
51 100159 MS 10-32 X 3/4 PH PAN BLK ZINC
52 049410 POWER PCB ASSY
53 049084 TUNER ASSY/RAA1
54 004903 TUNER COVER
55 101097 TS 6-32 X 3/16 PHIL PAN TAP
56 005070 REAR PANEL
57 117711 AC RECEPT WITH LINE FILTER
58 102001 KEP NUT 4-40 CADMIUM PLATE
59 102020 MACH NUT: 6-32 SELF-LOCK
60 005078 REAR PANEL PLUG
61 100250 SEMS MS 6-32 X 1/4 PHIL PAN
62 101114 SM 4-24 X 1/2 PHIL PAN TYPE A
63 101109 TS 6-32 X 5 /16 PHIL PAN TAPTITE
Ref.
No.
Part
No. Description

2625
EXPLODED VIEW

REPACKING INSTRUCTION
AM/FM TUNER
INCLUDING TM1 TUNER MODULE OPTION
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
informationonly.
McINTOSH LABORATORY, INC., 2 CHAMBERS STREET, BINGHAMTON, NEW YORK 13903 Printed in U.S.A. Part Number 040724
27