mac 1500 stereo receiver
Contents
1. WARRANTY STATION SERVICE MANUAL MAC 1500 STEREO RECEIVER AOLELE esee ERREBAL CONTENTS INTRODUCTION 1 FM ALIGNMENT CHART 2 3 MULTIPLEX DECODER ALIGNMENT CHART _ 4 5 SCHEMATIC 6 7 TESTS AND ADJUSTMENTS 8 DIAL STRINGING 8 PARTS LIST 9 14 TOP AND BOTTOM VIEWS 15 SPECIFICATIONS 16 BLOCK DIAGRAM 16 McINTOSH AUDIO COMPANY 2 Chambers St Binghamton N Y 13903 00S LOVIN MAC 1500 STEREO RECEIVER INTRODUCTION All McIntosh tuners are carefully aligned and tested at the factory using the finest available test equipment All McIntosh tuners will meet their published specifica tions when shipped from the factory After extensive operation especially when tubes have been replaced it may be desirable to realign the timer circuits for best performance This manual gives complete information on the circuit realignment procedure for the MAC 1500 receiver The test equipment listed below or its equivalent is necessary to properly align a MAC 1500 The accuracy of the alignment will be directly related to the accuracy and calibration of the test equipment used FM Signal Generator Measurements 210A or equivalent VTVM Multiplex Generator RCA WR514A or equivalent 107 MC Generator Preferably crystal controlled Oscilloscope Hewlett Packard 120B or equivalent Harmonic Distortion Analyzer Hewlett Packard 330B or equivalent If the necessary test equipment is not availabl2. McINTOSH AUDIO COMPANY 2 Chambers St Binghamton N Y 13903 Made InU S A Phong Area Code 607 723 5491 Design subject to change without notice 038 133 Printed in U S A 062003
3. 036 C 9 Ceramic Feed Thru 001MFD 061 036 C 10 Ceramic Disc 10PF 20 NPO 061 009 C 11 Ceramic Tubular 5PF 25 061 005 150 13 Ceramic Disc 005 80 2096 061 040 C 16 Ceramic Disc 10PF 20 NPO 061 009 C47 Ceramic Tubular 25PF 061 003 C 18 Ceramic Disc 10PF 2096 NPO 061 009 C 19 Ceramic Feed Th ru 001 MFD 061 036 C 20 Ceramic Feed Thru 001MFD 061 036 C 21 Ceramic Feed Thru 1001 MED 061 036 C 22 Ceramic Disc 005MFD 80 20 061 040 23 Ceramic Disc 10PF 2096 NPO 061 009 C 24 Ceramic Disc 005 80 20 061 040 27 Ceramic Feed Thru 001 061 036 C 28 Ceramic Feed Thru 001MFD 061 036 C 29 Ceramic Disc 005MFD 80 20 061 040 C 30 Ceramic Disc 01 MFD 80 209 061 043 HEM CAPACITORS PART NO DESCRIPTION CAPACITANCE VOLTAGE TOLERANCE NUMBER C 31 Ceramic Disc 12PF 2096 NPO 061 010 32 Ceramic Disc 1MPD 80 20 061 049 C 33 Ceramic Disc 005MFD 80 2095 061 040 34 Ceramic Disc 005MFD 80 20 061 040 35 Ceramic Disc 01MFD 80 20 061 043 36 Ceramic Tubular 15PF 75 061 012 150 37 Flat Foil 40V 2096 064 027 C 38 Ceramic Feed Thru 001 MFD 061 036 C 40 Ceramic Feed Thru 001 MFD 061 036 C 41 Ceramic Feed Thru 001 MFD 061 036 42 Ceramic Feed Thru 001 MFD 061 036 C 43 Ceramic Disc 1MFD 80 20 061 049 44 Ceramic Disc 005MFD 80 20 061 040 45 Ceramic Disc 005MFD 80 2096 061 040 C 46 Ceramic Disc 6 8PF 2096 NPO 061 008 C 47 Ceramic Disc 12PF
4. 064 020 119 Electrolytic 60 40MFD 500V 500V 066 026 C 120 Electrolytic 40 40 40 MFD 450V 300V 150V 066 032 C 121 Tubular 50MFD 50V 066 014 C 122 Tubular 100MFD 12V 066 018 C 123 Tubular 50MFD 50V 066 014 C 124 Electrolytic 50 50 50 200V 200V 066 036 50MFD 200V 200V C 125 Ceramic Disc 001 061 035 C 126 Ceramic Feed Thru 001 MFD 061 036 C 127 Ceramic Disc 005MFD 80 20 061 040 C 128 Fixed Composition 18PF 1096 069 001 C 129 Fixed Composition 18PF 1095 069 001 C 130 Ceramic Tubular 430PF 596 061 031 C 131 Ceramic Disc 02MFD 80 2095 061 045 C 132 Ceramic Tubular 5PF 25 061 007 220 133 Ceramic Disc 1SOPF 2096 061 025 C 134 Ceramic Disc 150PF 2095 061 025 C 135 Ceramic Disc 4 7PF 2096 NPO 061 004 COILS ITEM PART NO DESCRIPTION VALUE NUMBER L 1 Antenna Coil 122 035 L2 R F Coil 1 22 054 L 3 Mixer Coil 122 055 L 4 OSC Coil 122 056 L 5 Peaking Coil 19KC 122 008 L 6 Filter Coil 67KC Trap 122 009 L 7 Neutralizing Choke 2 5 Micro H 3 122 033 L 8 Parasitic Choke 122 028 L 9 RF Choke 1 2 Micro H 122 011 L 10 RF Choke 1 2 Micro H 122 011 L 11 RF Choke 1 2 Micro H 122 011 L 12 RF Choke 1 2 Micro H 122 011 L 13 RF Choke 1 2 Micro H 122 011 L 14 RF Choke 1 2 Micro H 122 011 L 15 RF Choke 1 2 Micro H 122 011 L 16 RF Choke 1 2 Micro H 122 011 L 17 RF Choke 1 2 Micro H 122 011 L 16 RF Choke 75 Micro H 122 013 L 19 Peaking Coil 38 Micro H 122 014 L 20 Filter Coil Lo Pass 122 015 L 21 Filler Coil Lo Pass 122 015
5. 20 NPO 061 010 C 48 Ceramic Disc 47PF 20 470 061 019 C 49 Ceramic Feed Thru 100PF 20 061 021 50 Ceramic Disc 02MFD 80 20 061 045 C 51 Silver Mica 0027MFD 100V 596 063 004 52 Ceramic Disc 100PF 1096 N1500 061 023 C 53 Ceramic Disc 001MFD 061 035 C 54 Ceramic Disc 001MFD 061 035 C 55 Ceramic Disc 02MFD 80 20 061 045 56 Silver Mica 0012MFD 100V 596 063 002 C 57 Silver Mica 0012MFD 100V 596 061 002 C 58 Electrolytic 100MFD 3V 066 047 C 59 Ceramic Disc _1MFD 80 20 061 049 60 Ceramic Disc 220PF 2096 061 028 C61 Silver Mica 0047MFD 5 063 005 C 62 Silver Mica 0047MFD 5 063 005 C 63 Ceramic Disc 005MFD 80 20 061 040 64 Ceramic Disc 005MFD 80 2096 061 040 C 65 Ceramic Disc 005MFD 80 20 061 040 66 Ceramic Disc 005MFD 80 2096 061 040 C 67 Ceramic Disc 330PF 10 061 029 68 Ceramic Disc 330PF 10 061 029 69 Ceramic Tubular 430PF 5 061 031 70 Ceramic Tubular 430PF 596 061 031 C 71 Ceramic Disc 01MFD 80 20 061 043 72 Ceramic Disc 01 MFD 80 20 061 043 C 73 Flat Foil 22MFD 40V 20 064 024 74 Flat Foil 22MFP 40V 2096 064 024 C 75 Ceramic Disc 10PF 20 NPO 061 009 C 76 Flat Foil 22MFD 40V 20 064 024 77 Flat Foil 22MFD 40V 20 064 024 C 7B Ceramic Disc AMFD 80 20 061 049 79 Ceramic Disc AMFD 80 20 061 049 C 80 Electrolytic 100MFD 12V 066 018 C 81 Electrolytic 100MFD 12V 066 018 C 82 Ceramic Disc AMFD 80 20 061 049 C 83 Ceramic Disc 1MFD 80
6. 36 339 R 68 150K 5 VN 136 371 R 69 150 5 VAN 136 371 R 70 1M 10 VW 136 303 R 71 1M 10 VN 136 303 R 72 4 7M 1096 VN 1 36 374 R 73 4 7M 10 VN 136 374 R 74 6 8K 1096 VN 136 368 R 75 6 8K 10 VAN 136 368 76 1 8 10 VAN 136 381 77 1 8K 1096 VAN 136 381 R 78 470K 1096 VN 136 373 R 79 470K 1095 VAN 136 373 R 80 1M 1096 VAN 136 303 R 81 1M 1096 VW 1 36 303 R 82 47M 10 VAN 136 374 R 83 47M 1096 VN 136 374 R 84 1K 1096 VW 136 296 R 85 1K 1096 VW 136 296 R 86 1M 1096 VAN 136 303 R 87 1M 10 VN 1 36 303 R 88 1 2K 5 VAN 136 394 R 89 12K 596 VAN 136 394 R 90 100K 1096 VN 136 301 R 91 100K 10 VN 136 301 R 92 27K 10 VAN 136 379 R 93 27K 1096 VN 136 379 H 94 220K 1096 VAN 136 372 R 95 220K 1096 VN 1 36 372 R 96 680 ohms 10 WW 136 378 R 97 630 ohms 1095 VAN 136 378 R 98 15K 10 VAN 136 377 R 99 15K 1096 VAN 136 377 R 100 3 3M 10 VN 136 380 R 101 3 3M 1096 VAN 136 380 R 102 I30K 596 VAN 136 387 R 103 180K 596 VN 136 387 R 104 47K 1096 VN 136 339 R 105 47K 10 VAN 136 339 R 106 22K 1096 VN 136 369 R 107 47K 1096 VAN 1 36 339 R 108 22K 10 VAN 1 36 369 R 109 47K 10 VAN 136 339 R 110 47K 5 VN 136 388 R 111 47K 5 VN 136 388 R 112 1M 1096 VAN 136 303 R 113 1M 10 YANN 136 303 R 114 1M 1096 VN 136 303 R 115 1M 10 VAN 136 303 116 27 10 VN 136 379 R 117 27K 1096 VAN 136 379 R 118 100K 10 VN 136 301 R 119 100K 1096 VAN 136 301 R 120 470K 1096 VAN 136 373 R 121 470K 10 VAN 136 373 R 122 18K 10 136 386 123
7. Audio Amplifier 2N3391A 132 004 Q 7 Left Channel Audio Amplifier 2N3391A 132 004 Q 8 Right Channel Audio Amplifier 2N3391A 132 004 Q 9 Left Channel Low Level Amplifier 2N3391A 132 004 Q 10 Right Channel Low Level Amplifier 2N3391A 132 004 Q 11 Left Channel Emitter Follower 2N3391A 132 004 Q 12 Right Channel Emitter Follower 2N3391A 132 004 Q 13 Left Channel Low Level Amplifier 2N720A 132 002 Q 14 Right Channel Low Level Amplifier 2N720A 132 002 Q 15 Left Channel Emitter Follower 2N339IA 132 004 0 16 Right Channel Emitter Follower 2N3391A 132 004 Q 17 Left Channel Emitter Follower 2N3391A 132 004 Q18 Right Channel Emitter Follower 2N3391A 132 004 Q 19 Left Channel Voltage Amplifier 2N720A 132 002 Q 20 Right Channel Voltage Amplifier 2N720A 132 002 DIODES ITEM DIODE PART NO DESCRIPTION NUMBER NUMBER D 1 Diode 1 070 022 D2 Diode 5 022 0 3 Diode FD100 070 022 D 4 Diode FD100 070 022 D 5 Diode FD100 070 022 Diode Matched pair 1N542 IN542 070 003 0 7 Diode Matched pair 1N542 1N542 070 003 D 8 Diode Matched pair 1N542 1N543 070 003 D 9 Diode Matched pair 1N542 IN542 070 003 D 10 Diode Matched pair 1N542 070 003 D 11 800 PIV 750MA Silicon Rectifier 070 017 D 12 600 PIV 750MA Silicon Rectifier 070 016 D 13 600 PIV 9 750MA Silicon Rectifier 070 016 D 14 800 PIV 750MA Silicon Rectifier 070 017 D 15 400 PIV 9 750MA Silicon Rectifier 070 015 D 16 10 V 400 MW Zener Rectifier 070 011 10 CONTROLS ITEM PART NO FUN
8. R 173 18K 10 VAN 136 163 R 174 220 ohms 10 5W 139 009 R 175 220 ohms 1096 5W 139 009 R 176 220 ohms 10 5W 139 009 R 177 1 5K 20 2W 136 329 R 178 1M 10 VAN 136 303 R 179 1M 1096 VAN 136 303 R 180 1K 10 VAN 136 110 MSI 1K 1096 VAN 136 110 R 182 470K 1096 VAN 136 222 R 183 27K 1096 VAN 136 379 R 184 27K 10 VAN 136 379 R 185 1M 10 VAN 136 303 R 186 1M 1096 VAN 136 303 R 187 1K 10 VW 136 110 R 188 10K 10 VAN 136 382 R 189 100 ohms 10 YAN 136 068 R 190 1K 10 VAN 136 296 R 191 470K 10 VAN 136 373 MISCELLANEOUS Lamp MPX 1850 058 006 Knob 4 without index Tuning 043 479 Lamp Incandescent 1866 058 014 Knob 1 with index Volume Dial Glass 016 052 Selector Balance 043 480 Extrusion Glass 016 053 Knob 1 amp with index Bass Treble 090 070 End Cap 018 080 Knob 34 with index Bass Treble 090 071 Lower Panel Extrusion 018 094 Upper Panel Extrusion 018 095 Fuse 3 2 Amp Slo Blo 089 006 Tuning Meter 124 006 Tone Control Module 130 007 Rumble and HF Module 130 025 MAC 1500 TOP and BOTTOM VIEWS V 15 V 14 V13 BIAS ADJUST CONTROLS V12 V4 j OUTPUT POWER TRANSFORMERS TRANSFORMER LEFT RIGHT V10 v9 OSCILLATOR V11 COIL TRIMMER V2 COIL 12AU7 V8 MISER TRIMMER 6EA8 V7 LEFT AND RIGHT PRE AMP PRINTED CIRCUIT BOARDS TRIMMER COIL BE 9 2 Vi ANTENNA 42 gt COIL TUNING CONDENSER COVER V4 MUTE ADJUST CONTROL 2 13 3RD IF TRANSFORMER 4TH IF TRANSFORMER
9. 1 2db per octave BLOCK DIAGRAM TUNING Filler cutoff frequency 5KC attenuation rale 1 2db per octave SPECIAL FEATURES a Loudness control for full fidelity listening levels b Tape monitor switch for listening to recorded tope program white recording c Tone controls are clutched for tracking opera of left and right channels or independent operation Headphone output fed from special tap on output transformer for maximum signal to noise ratio Speakers may be automatically muted when head phone plug is inserted by use of rear mounted Switch Silicon transistors used in all preamplifier stages for low noise and hum free operation f High quality epoxy circuit boards for reliable long life performance g High quality conservatively operated components ore used throughout for long life h Zener regulated power supply is used for critical circuits i Equalization and tone control circuits are feed back type for lowest distortion and greatest accu racy d I MISCELLANEOUS FINISH Gold anodized panel and knobs black finished chassis DIMENSIONS 16 wide 5 high 16 deep WEIGHT 40 Ibs shipping weight 54 Ibs POWER CONSUMPTION 180 watts 120 volts 60 cps TRANSISTOR AND TUBE COMPLEMENT 19 silicon transistors 1 germanium transistor 15 tubes 1 6 diodes rectifier and zener diode 38 OSCILLATOR MAC 1500 STEREO RECEIVER BLOCK DIAGRAM
10. 18 10 VN 136 386 13 14 RESISTORS ITEM PART NO RESISTANCE TOLERANCE WATTAGE NUMBER R 124 7 5 5 YAW 136 376 R 125 4 7K 10 VAN 136 298 R 126 7 5K 596 136 376 R 127 4 7K 1096 VAN 1 36 298 R 128 150 ohms 10 YAW 136 294 R 129 150 ohms 10 YAW 136 294 R 130 5 6K 5 VAN 136 397 131 5 6 5 VAN 136 397 R 132 3 3K 10 VAN 136 131 R 133 3 3K 1096 VAN 136 131 R 134 100 ohms 595 VAN 136 067 R 135 100 ohms 596 VW 136 067 R 136 330K 1096 VAN 136 215 R 137 330K 1096 VAN 136 215 R J3S 15K 10 VW 136 159 R 139 15K 1096 136 159 R 140 1 2M 1096 VAN 136 240 R 141 1 2M 1096 VAN 136 240 R 142 18K 10 1W 136 313 R 143 18K 10 1W 136 313 R 144 27K 10 1W 136 316 R 145 27K 10 1W 136 316 R 146 30K 596 1W 136 317 R 147 30K 596 1W 136 317 R 148 220K 10 YAW 136 372 R 149 220K 10 YAW 136 372 R 150 220K 10 VN 136 372 R 151 220K 10 VAN 136 372 R 152 22K 1096 136 166 R 153 4 7K 10 136 138 R 151 4 7K 10 VW 136 138 R 155 4 7K 10 VAN 136 138 R 156 4 7K 10 136 138 157 15ohms 596 1W 139 034 R 158 15ohms 5 1W 139 034 R 159 15 ohms 596 1W 139 034 R 160 15 ohms 5 1W 139 034 R 161 1 8K 595 VAN 136 120 R 162 1 8 5 VAN 136 120 R 163 47 ohms 20 2W 1 36 323 R 164 47 ohms 20 2W 1 36 323 R 165 2 2M 1096 VW 136 250 R 166 900 ohms 10 5W 139 012 R 167 3 6 10 5W 139 013 R 168 33K 10 YN 136 173 R 169 33K 10 VAN 136 173 R 170 6K 10 5W 139 033 R 171 6K 1096 5W 139 033 R 172 8 2K 1096 1W 136 31 1
11. 20 061 049 C 84 Ceramic Disc 0012MFD 10 061 051 85 Ceramic Disc 0012MFD 1096 061 051 C 86 Ceramic Tubular 430PF 596 061 031 C 87 Ceramic Tubular 430PF 596 061 031 C 88 Flat Foil 22MFD 40V 20 064 024 89 Flat Foil 22MFD 40V 20 064 024 90 Flat Foil 22MFD 40V 2096 064 024 C 91 Flat Foil 22MFD 40V 20 064 024 C 92 Molded Film 22MFD 200V 20 064 013 C 93 Molded Film 22MFD 200V 20 064 013 C 94 Electrolytic 100MFD 12V 066 018 C 95 Electrolytic 100MFD 12V 066 018 C 96 Mylar 47MFD 100V 10 064 019 97 Mylar 7MFD 10CV 10 064 019 C 98 Ceramic Disc 0015MFD 10 061 038 C 99 Ceramic Disc 0015MFD 1096 061 038 C 100 Flat Foil 047MFD 40V 2096 064 036 C 101 Flat Foil 047MFD 40V 2096 064 036 C 102 Electrolytic 100MFD 3V 066 047 C 103 Electrolytic 100MFO 3V 066 047 C 104 Ceramic Disc 47PF 20 N470 061 019 C 105 Ceramic Disc 47PF 20 N470 061 019 C 106 Mylar 25MFD 400V 10 064 016 C 107 Mylar 25MFD 400V 10 064 016 C 108 Mylar 600V 10 064 012 109 600V 10 064 012 lt 1 9 Mylar AMFD 600V 1096 064 012 11 Mylar AMFD 600V 10 064 012 C 112 Ceramic Tubular 430 PF 596 061 031 C 113 Ceramic Tubular 430PF 596 061 031 12 CAPACITORS ITEM PART NO DESCRIPTION CAPACITANCE VOLTAGE TOLERANCE NUMBER C 114 Mylar AMFD 125V 1096 064 028 C 115 Mylar 125V 1096 064 028 C 116 Ceramic Disc 005MFD 1400V 061 052 117 Ceramic Disc 005MFD 1400V 061 052 118 Mylar A7MFD 200 10
12. CTION RESISTANCE NUMBER R 1 Balance Control 500K 500K 134 165 R2 Bass Control IM 1M 134 117 R 3 Treble Control 500K 500K 134118 4 Volume Control 60K 60K 134 164 R 5 Muting Adjust Control 100K 134 102 R 6 Driver Balance Control 5K 134 103 R7 Driver Balance Control 5K 134 103 R 8 Bias Adjust Control 100K 134 102 R 9 Bias Adjust Control 100K 134 102 R 10 Bias Adjust Control 100K 134 102 R 11 Bias Adjust Control 100K 134 102 R 12 MPX Light Adjust Control 100K 134 102 R 55 Left Channel Gain Control 5K 134 120 SWITCHES ITEM PART NO FUNCTION DESCRIPTION NUMBER 5 1 Rotary Switch Input Selector 1 46 096 SS 26 19 32 Trigger Slide Switch Muting On Off 148 003 SS 50 7 32 Trigger Slide Switch Speaker On Off 148 006 SS 50 19 32 Trigger Slide Switch S used Stereo Mono Tape Monitor 148 007 LF and HF Fillers Loudness TRANSFORMERS ITEM PART NO FUNCTION NUMBER T 1 FM IF 162 005 T 2 FM IF 162 004 T 3 FM IF 162 004 T 4 IF Muting 162 029 T 5 FM Discriminator 162 027 T 6 19KC Amplifier 162 010 T 7 38KC Oscillator 162 009 T8 Balun 076 006 T 9 Output Left 159 062 T 10 Output Right 159 062 MI Power 159 061 CAPACITORS ITEM PART NO DESCRIPTION CAPACITANCE TOLERANCE NUMBER C 1 Variable FM 059 006 C 2 Trimmer Ceramic 1 8 PF 060 001 C3 Trimmer Ceramic 1 8 PF 060 001 C 4 Trimmer Glass 060 002 C5 Ceramic Disc OOSMFD 80 20 061 040 C6 Ceramic Disc 001 061 035 7 Ceramic Disc 001 MFD 061 035 C 8 Ceramic Feed Thru 001MFD 061
13. NMENT TEST REMARKS LIMITS Before making any adjustments set the controls as follows a Input selector switch to FM mono b Volume control maximum CCW c Muting pot maximum CW d Muting OUT e Stereo light adjust maximum CW Top secondary Maximum pos Shunt to ground the winding not being adjusted Do this with a 01 and bottom sible negative MFD capacitor in series with a 1K resistor Attenuate signal generator primary of voltage until output voltage at 1 is less than 1 5 volts with one IF trans T1 T2 T3 former winding shunted IF transformers have terminal 1 marked with a green dot and are numbered clockwise Primary and Maximum pos Muting pot MUST be maximum CW secondary of sible negative T4 voltage should be 20 to 30 volts Secondary Adjust for O volts The primary bottom of T 5 should be adjusted only if a distortion top of analyzer is available T 5 4 Maximum nega tive voltage L 4 SAME Repeat steps 4 and 5 until dial calibration is accurate C 2 C 3 SAME As output increases attenuate signal generator to keep maximum out put at TP 1 to less than 1 volt L 1 L 2 L3 SAME Repeat steps 6 and 7 until output is as high as possible Primary bottom 0 5 distortion Use a strong signal from the FM generator Adjust T 5 primary for of T 5 or less minimum distortion IF A DISTORTION ANALYZER IS NOT AVAILABLE OMIT THIS STEP DO NOT ADJUST T 5 PRIMARY L 2 3 Mini
14. RESISTORS ITEM PART NO RESISTANCE TOLERANCE WATTAGE NUMBER R 13 47K 10 YAN 136 339 R 14 100 ohms 10 TV2VV 136 068 R 15 15K 1096 VW 136 377 R 16 3 3K 10 VN 136 385 R 17 220 ohms 1096 YAW 136 396 R 16 1K 10 VW 136 110 R 19 470K 10 VAN 136 373 R 20 1M 1096 VAN 136 236 21 100 ohms 10 136 068 22 1 10 VAN 136 110 R 23 100 ohms 1096 YW 136 068 R 24 10K 10 VAN 136 152 R 25 10M 1096 136 278 26 47 10 VAN 136 339 R 27 470K 1096 VAN 196 222 25 100K 10 VAN 136 301 R 29 1K 1096 VAN 136 110 R 30 6 8K 1096 VAN 136 145 R 31 220K 10 136 372 R 32 470K 10 YAW 136 373 R 33 47K 10 VAN 136 180 R 34 470K 10 VAN 136 373 R 35 2 2K 10 136 124 RESISTORS ITEM PART NO RESISTANCE TOLERANCE WATTAGE NUMBER R 36 220 ohms 10 VAN 136 082 R 37 10K 1096 VAN 136 382 R 38 10K 1096 VAN 136 382 R 39 22K 10 YW 136 166 R 40 39K 10 VAN 136 370 H 41 2 2K 1096 VAN 136 367 R 42 IK 10 136 110 43 1M 10 VAN 136 303 R44 470 ohms 1096 VAN 136 295 R 45 4 7K 10 VAN 136 298 R 46 2 7K 10 VAN 136 297 47 1M 10 VAN 136 303 48 1 10 VAN 136 303 R 49 1M 1096 vew 136 236 R 50 4 7K 10 VAN 136 298 51 1 2K 1096 VN 136 114 R 52 1K 1096 VW 136 296 R 53 4 7K 10 VAN 136 298 R 54 100K 40 vaN 136 301 R 60 220K 10 VAN 136 372 R 61 100K 1096 YAW 136 301 R 62 6 8K 10 VN 136 145 R 63 22K 1096 VAN 136 369 R 64 47K 1096 136 339 65 47 10 136 339 66 47 10 VN 136 339 R 67 47K 10 VW 1
15. V5 Q3 Q4 Q2 Io IF TRANSFORMER 2 2K V6 DISCRIMINATOR TRANSFORMER 19KC PHASE COIL INJECT 107 MC SIGNAL HERE Q7 Q5 Q8 Q6 LOW PASS FILTER MPX INPUT ac A ANTENNA COIL WHITE WIRE 7 KG LTER RECOIL MIXER COIL 19 KC TRANSFORMER 38 KC TRANSFORMER 15 FM TUNER SECTION USABLE SENSITIVITY lot 10096 modulation 2 5uV LH F Standards SIGNAL TO NOISE AND HUM RATIO 65db HARMONIC DISTORTION Mono less than 5 Stereo less than 8 DRIFT less than 25KC FREQUENCY RESPONSE Flat from 20 cps to 20KC with standard 75 second deemphasis and 19KC pilot frequency filter CAPTURE RATIO Better than 2 0db IMAGE REJECTION Better than 60db STEREO MULTIPLEX SEPARATION Better than 30db at 1 KC SPECIAL FEATURES Automatic stereo switching b Muting IF Injected circuit with at least 50db quieting between stations c Antenna inputs for 300 ohm balanced for twin lead and 75 ohm unbalanced for coaxial cable d Nuvistor RF amplifier Nuvistor mixer e Four stages of IF amplification with AGC used to insure that limiting occurs only in the limiter stages f Two limiter stages used for exceptional capture ratio and smooth muting operation 9 Multiplex filter and SCA filter to suppress 19KC and 38KC signal components at least 40db below program and to suppress 67KC SCA by 60db h Noise immune logic circuit used to activate MPX stereo light and automatic stereo switc
16. e alignment should not be attempted You may contact the McIntosh Customer Service Department for additional information Customer Service McIntosh Laboratory Inc 2 Chambers Street Binghamton New York Our telephone number is 723 5491 The direct dial area code is 607 MAC 1500 TUNER SIGNAL GENERATOR INDICATOR STEPS DIAL SETTING FREQ COUPLING MODULATION Point of no 10 7MC Through external CW VTVM TP 1 interference 01 MFD capacitor 1 and no signal to mixer grid pin 4 6054 V2 SAME SAME SAME SAME SAME Pin 1 of T4 2 SAME SAME SAME SAME SAME 2 3 105MC 105MC 300 ohm antenna 400 cycles VTVM connected to TPZ2 and 4 terminals with 75KC deviation scope connected to LorRtape matching network 100 modulation output 5 90MC 90MC SAME SAME SAME 6 105MC 105MC SAME SAME SAME 7 90MC 90MC SAME SAME SAME 90MC 90MC SAME SAME VTVM connected to TP 2 8 scope and distortion analyzer connected to L or R tape output 105MC and 105MC SAME 50 cps 150KC See note at bottom of page 9 90MC and deviation Approx 90MC 5 microvolts at antenna terminals 90MC 90MC SAME 400 cycles Scope connected to L or R 10 75KC deviation tape output 10096 modulation 90MC 90MC SAME SAME VTVM connected to 1 METHOD OF CONNECTING EQUIFMENT TO DISPLAY OVERALL RESPONSE CURVE ON SCOPE Scope and distortion analyzer 11 connected to L or R tape output FM ALIG
17. hing on 19KC stereo pilot only i D Arsonval tuning meter channel tuning i Flywheel tuning for ease of operation and precise tuning lor accurate center of OUT HD O SPECIFICATIONS AMPLIFIER SECTION POWER OUTPUT 60 watts continuous 30 watts per channel 65 watts total music power I H F Stand ards HARMONIC DISTORTION less than 0 5 30 cps to 20KC both channels operating at rated output at the same time INTERMODULATION DISTORTION Less than 0 5 for any combination of frequencies from 30 cps to 20KC at rated output equivalent RMS watts decreases as output power is reduced FREQUENCY RESPONSE 0 5db 20 cps to 20KC Power amplifier response is 2 cps to 150KC at power bandwidth is 19 cps to 30KC OUTPUT IMPEDANCE 4 8 and 16 ohms Rated out put is delivered by any of these impedances DAMPING FACTOR Greater than 1 0 INPUT SENSITIVITY AND IMPEDANCE Tape Head 2 8MV 1 megohm Phono 1 5 6MV 47K ohms Phono 2 2 8MV 47K ohms Aux 400MV 500K ohms Tape Monilor 400MV 500K ohms TAPE OUTPUT LEVEL Tuner 1 2 volts for other Inputs 400 at rated sensitivity HUM AND NOISE Power Amplifier 90db High Level Inputs 75db Low Level Inputs 60db TONE CONTROL RANGE Bass control 1 5db to 1 8db at 50 cps Treble control 1 5db to 15 db at 10KC L F and H F FILTER L F filter cutoff frequency 50 cps attenuation rate
18. hould be at least 40db below modulated output MPX light adjust control R 12 Turn control until light comes on Then back off just enough to cause the light to go off Then back off about 1 8o0f a turn more Light should operate ONLY on a MPX signal s ts 1 i n 4 ETRAS SOR 2 1 a Y AC aet doen or E 7 Seat ru asse mar were 2 Me mM cr Sentus 00 He m PREAMP AMP TESTS AND ADJUSTMENTS All adjustments should be made after a minimum of a 10 minute warm up 1 Remove the 12AX7 V 9 2 Measure the voltage at Voltage should be 0 7 volts positive If it is not 0 7 volts ad just R 8 3 Do likewise with 4 and 9 5 and R 10 TP 6 and R 11 Re insert the 12AX7 Feed a 1 KC signal into AUX Drive the amp to full 30 watts output Be sure all controls are set for a flat response Check to be sure the channels have equal output with equal drive from the audio oscillator If channels are un balanced adjust R 55 This control is found on the left preamp printed circuit board It will vary the output of the left channel The preamp cover must be removed to gain access to
19. mum tilt Observe direction of tilt of overall response curve at 105MC and 90MC If direction is the same adjust L 2 at 100MC for minimum tilt Re check tilt at 90MC and 105MC If direction is not the same adjust L 2 at 90MO and L 3 at 105 for minimum tilt Check tilt again at 100MC Muting threshold control With FM generator set for 2 5 microvolts output place muting control to IN Adjust the muting threshold control to the point at which the sine wave on the scope becomes erratic IHFM Sensitivity 2 5 microvolts for 396 total noise and distortion Step 11 is an overall sensitivity check It requires a distortion analyzer and FM signal generator with attenuator With 2 5 microvolts input at the 300 ohm terminals 1 voltage should be 45 volts or more MAC 1500 MULTIPLEX TUNER SIGNAL GENERATOR INDICATOR STEPS DIAL SETTING FREQ COUPLING MODULATION CONNECTED Point of Audio gener 2 Audio L or R tape output 4 interference ator setto 67KC VTVM or signal 0 5 volts out put or less SAME MPX generator SAME DC Pin 9 of 6EA8 with 19KC pilot VTVM attenuated to approx 596 level 5 level 2 is Ye of normal 1096 level 19KC pilot MUST be at tenuated for correct align ment 100MC 100MC modu 300 ohm 1KC 100 modu Audio Pin 1 or 2 of T 7 lated by MPX antenna termi lation 34KC VIVM 3 generator nals with deviation modu 19KC
20. pilot at matching net lating left or normal output work See right only previous page SAME SAME SAME SAME Audio L or R tape output VTVM 4 5 5 SAME SAME SAME SAME SAME SAME 6 SAME SAME SAME SAME SAME SAME 7 SAME SAME SAME Turn off 1 KC audio SAME SAME modulation SAME Tune to a strong SAME MPX mono FM stereo 8 station indi cator light on receiver DECODER ALIGNMENT ADJUST TEST LIMITS REMARKS 67KC Trap L 6 Adjust for mini mum voltage Stereo light must be on This is done by adjusting the MPX Light Adj control R 12 T 6 top and bottom L 5 Adjust for maxi mum voltage Stereo light must be off T 7 bottom core SAME Stereo light must be completely on T 7 top core Adjust for stable 1 Turn off 19KC pilot on MPX generator scope display 2 Adjust upper core of T 7 to obtain a stable and uniform 1 KC signal scope display This adjustment may be critical so turn core very slowly 3 Turn 19KC pilot back on L 5 30db separation Modulate left channel and measure right channel output Adjust L 5 for or more minimum right channel output maximum separation Be sure all test leads are removed from TP 2 for separation tests SAME Modulate right channel and measure left channel output Separation in steps 5 and 6 should be at least 30db This step checks the rejection of 19KC and 38KC frequencies Residual output s
21. this control 6 Measure harmonic distortion at 30 cycles Ad just R 6 for minimum distortion on the left channel and R 7 for the right Distortion must be less than 0 5 The bottom cover must be removed to adjust these controls They have blue plastic knobs 7 Now measure distortion at 2KC and 20KC Must be less than 0 5 at full output 8 Next feed a signal thru the phono inputs Check for correct RIAA equalization 9 Remove all inputs Check hum and noise on phono 1 Should be at least 60db below rated output MAC 1500 PARTS LIST TUBES ITEM TUBE PART NO USE NUMBER NUMBER V 1 HF Amplifier 6DS4 165 013 V 2 Mixer 6DS4 165 013 V 3 1st IF Amplifier 6AU6 165 004 V 4 2nd IF Amplifier 6AU6 165 004 V 5 3rd IF Amplifier 1st Limiter 6AU6 165 004 V 6 4th IF Amplifier 2nd Limiter 6CS6 165 011 V 7 19KC Amplifier Indicator Control 6EA8 165 044 v 8 MPX 38KC Oscillator 12AU7 165 018 9 Voltage Amplifier 12AX7 165 019 V 10 Left Channel Driver 12AU7 165 018 11 Right Channel Driver 12AU7 165 018 V 12 Left Channel Output 7591 165 022 V 13 Left Channel Output 7591 165 022 V 14 Right Channel Output 7591 165 022 V 15 Right Channel Output 7591 165 022 TRANSISTORS ITEM TRANSISTOR PART NO USE NUMBER NUMBER Q 1 Local Oscillator TA2556 40244 132 008 Q 2 Control Amplifier 2N3638 132 007 0 3 MPX Lamp Control 132 010 Q 4 Oscillator On Qff Control 2N3391A 132 004 Q 5 Left Channel Audio Amplifier 2N3391A 1 32 004 Q 6 Right Channel
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