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McIntosh MAC1500 - SERVICE 1, Service Manual

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McIntosh MAC1500 - SERVICE 1 Service Manual Download Page 5

MAC 15 00 MULTIPLEX

STEPS

1

2

3

4

5

6

7

8

TUNER

DIAL

SETTING

Point of no

interference
or signal

SAME

100MC

SAME

SAME

SAME

SAME

SAME

SIGNAL GENERATOR

FREQ.

Audio gener-
ator set to 67KC

0.5 volts out-

put or less

MPX generator
with 19KC pilot

attenuated to
approx. 5%

level. (5% level

is ½ of normal

10% level).
19KC pilot

MUST be at-
tenuated for
correct align-

ment

100MC modu-

lated by MPX

generator.

19KC pilot at

normal output

SAME

SAME

SAME

SAME

Tune to a strong

mono FM
station

COUPLING

TP#2

SAME

300 ohm
antenna termi-

nals with

matching net-

work. (See *
previous page)

SAME

SAME

SAME

SAME

SAME

MODULATION

1KC 100% modu-

lation (34 KC
deviation) modu-
lating left or
right only

SAME

SAME

SAME

Turn off 1 KC audio
modulation

INDICATOR

TYPE

Audio

VTVM

DC
VTVM

Audio

VTVM

Audio
VTVM
and

scope

SAME

SAME

SAME

MPX
stereo

indi-

cator

light on
receiver

CONNECTED

TO

L or R tape output

Pin 9 of 6EA8

Pin

 1 or 2 of T-7

L or R tape output

SAME

SAME

SAME

4

Summary of Contents for MAC1500 - SERVICE 1

Page 1: ...TOSH AUDIO COMPANY 2 Chambers St Binghamton N Y 13903 MAC 1500 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 ...

Page 2: ...alent 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 WR51A or equivalent 10 7 MC Generator Preferably crystal controlled Oscilloscope Hewlett Packard 120B or equivalent Harmonic Distortion Analyzer Hewlett Pack...

Page 3: ...AME SAME SAME SAME SAME MODULATION cw SAME SAME 400 cycles 75KC deviation 100 modulation SAME SAME SAME SAME 50 cps 150KC deviation Approx 5 microvolts at antenna terminals 400 cycles 75KC deviation 100 modulation SAME INDICATOR TYPE VTVM SAME SAME CONNECTED TO TP 1 Pin 1 of T4 TP 2 VTVM connected to TP 2 and scopeconnected to Lor Rtape output SAME SAME SAME VTVM connected to TP 2 scope and distor...

Page 4: ... clockwise _ Muting pot MUST be maximum CW The primary bottom of T 5 should be adjusted only if a distortion analyzer is available Repeat steps 4 and 5 until dial calibration is accurate As output increases attenuate signal generator to keep maximum out put at TP 1 to less than 1 volt Repeat steps 6 and 7 until output is as high as possible Use a strong signal from the FM generator Adjust T 5 prim...

Page 5: ...u lated by MPX generator 19KC pilotat normal output SAME SAME SAME SAME Tune to a strong mono FM station COUPLING TP 2 SAME 300 ohm antenna termi nals with matching net work See previous page SAME SAME SAME SAME SAME MODULATION 1KC 100 modu lation 34KC deviation modu lating left or right only SAME SAME SAME Turn off 1 KC audio modulation INDICATOR TYPE Audio VTVM DC VTVM Audio VTVM Audio VTVM and ...

Page 6: ...iform 1 KC signal scope display This adjustment may be critical so turn core very slowly 3 Turn 19KC pilot back on Modulate left channel and measure right channel output Adjust L 5 for minimum right channel output maximum separation Be sure all test leads are removed from TP 2 for separation tests Modulate right channel and measure left channel output Separation in steps 5 and 6 should be at least...

Page 7: ...6 ...

Page 8: ...7 ...

Page 9: ... 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 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...

Page 10: ...t Channel Emitter Follower Right Channel Emitter Follower Left Channel Voltage Amplifier Right Channel Voltage Amplifier DIODES DESCRIPTION Diode Diode Diode Diode Diode Diode Matched pair 1N542 Diode Matched pair 1N542 Diode Matched pair 1N542 Diode Matched pair 1N542 Diode Matched pair 1N542 800 PIV 750MA Silicon Rectifier 600 PIV 750MA Silicon Rectifier 600 PIV 750MA Silicon Rectifier 800 PIV 7...

Page 11: ...nator 19KC Amplifier 38KC Oscillator Balun Output Left Output Right Power PART NUMBER 162 005 162 004 162 004 162 029 162 027 162 010 162 009 076 006 159 062 159 062 159 061 CAPACITORS 10 ITEM NO C 1 C 2 C 3 C 4 C 5 C 6 C 7 C 8 C 9 C 10 C 11 C 13 C 16 C 17 C 18 C 19 C 20 C 21 C 22 C 23 C 24 C 27 C 28 C 29 C 30 DESCRIPTION Variable FM Trimmer Ceramic Trimmer Ceramic Trimmer Glass Ceramic Disc Ceram...

Page 12: ...c Tubular CAPACITANCE 12PF 1MPD 005MFD 005MFD 01MFD 15PF 1MFD 001 MFD 001 MFD 001MFD 001MFD 1MFD 005MFD 005MFD 6 8PF 12PF 47PF 100PF 02MFD 0027MFD 100PF 001MFD 001MFD 02MFD 0012MFD 0012MFD 100MFD _1MFD 220PF 0047MFD 0047MFD 005MFD 005MFD 005MFD 005MFD 330PF 330PF 430PF 430PF 01MFD 01MFD 22MFD 22MFP 10PF 22MFD 22MFD 1MFD 1MFD 100MFD 100MFD 1MFD 1MFD 0012MFD 0012MFD 430PF 430PF 22MFD 22MFD 22MFD 22M...

Page 13: ... 200V 200V 200V VALUE 19KC 67KC Trap 2 5 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 1 2 Micro H 75 Micro H 38 Micro H Lo Pass Lo Pass TOLERANCE 10 10 10 80 20 10 10 5 80 20 25PF N220 20 20 20 NPO 3 PART NUMBER 064 028 064 028 061 052 061 052 064 020 066 026 066 032 066 014 066 018 066 014 066 036 061 035 061 036 061 040 069 001 069 001 0...

Page 14: ... 10 10 10 10 10 10 10 10 10 J0 10 10 10 10 10 10 10 10 5 5 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 5 5 10 10 10 10 10 10 10 10 10 10 10 10 5 5 10 10 10 10 10 10 5 5 10 10 10 10 10 10 10 10 10 10 10 10 WATTAGE W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W PART NUMBER...

Page 15: ...0 10 WATTAGE W W W W W W W W W W W W W W W W W W 1W 1W 1W 1W 1W 1W W W W W W W W W W 1W 1W 1W 1W W W 2W 2W W 5W 5W W W 5W 5W 1W W 5W 5W 5W 2W W W W W W W W W W W W W W W PART NUMBER 136 376 136 298 136 376 1 36 298 136 294 136 294 136 397 136 397 136 131 136 131 136 067 136 067 136 215 136 215 136 159 136 159 136 240 1 36 240 136 313 136 313 136 316 136 316 136 317 136 317 136 372 136 372 136 372 ...

Page 16: ...2ND IF TRANSFORMER 1ST IF TRANSFORMER INJECT 10 7 MC SIGNAL HERE MIXER COIL 15 TUNING CONDENSER COVER ANTENNA COIL V14 V15 V12 V13 V1 TRIMMER COIL V 2 V10 V 9 V11 LEFT RIGHT OSCILLATOR COIL TRIMMER 6EA8 V7 12AU7 V8 COIL RFCOIL LOW PASS FILTER ANTENNA COIL 67 KC FILTER 38 KC TRANSFORMER 19 KC TRANSFORMER MPX INPUT WHITE WIRE Q7 Q5 Q8 Q6 19KC PHASE COIL DISCRIMINATOR TRANSFORMER V 5 Q3 Q4 Q 2 2 2K V...

Page 17: ...b 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 400MV at rated sensitivity HUM AND NOISE P...

Page 18: ...MclNTOSH 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 Printed in U S A 038 133 BE062003 ...

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