McIntosh MAC1500 Receiver Service Manual.pdf

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1、WARRANTY STATION SERVICE MANUAL STEREO RECEIVER CONTENTS INTRODUCTION 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 Chambe

2、rs St., Binghamton, N. Y. 13903 *IH VYi 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 op

3、eration, especially when tubes have been replaced, it may be desirable to realign the tuner 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 proper

4、ly 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) Oscillosc

5、ope (Hewlett-Packard 120B or equivalent) Harmonic Distortion Analyzer (Hewlett-Packard 330B or equivalent) If the necessary test equipment is not available, alignment should not be attempted. You may contact the McIntosh Customer Service Department for additional information. Customer Service McInto

6、sh Laboratory, Inc. 2 Chambers Street Binghamton, New York Our telephone number is 723-5491 The direct dial area code is 607 1 MAC 1500 TUNER SIGNAL GENERATOR STEPS DIAL SETTING FREQ. COUPLING MODULATION Point of no interference and no signal 10.7MC Through external .01 MFD capacitor to mixer grid (

7、pin 4 or 6DS4, V2) cw SAME SAME SAME SAME SAME SAME SAME SAME 105MC 105MC 300 ohm antenna terminals with matching network* 400 cycles 75KC deviation (100% modulation) 90MC 90MC SAME SAME 105MC 105MC SAME SAME 90MC 90MC SAME SAME 90MC 90MC SAME SAME 105MC and 90MC 105MC and 90MC SAME 50 cps 150KC dev

8、iation Approx. 5 microvolts at antenna terminals 90MC 90MC SAME 400 cycles 75KC deviation (100% modulation) 90MC 90MC SAME SAME INDICATOR TYPE CON CONNECTED TO VTVM TP# 1 SAME Pin 1 of T4 SAME TP#2 METHOD OF CONNECTING EQUIPMENT TO DISPLAY OVERALL RESPONSE CURVE ON SCOPE SCOPE AUDIO OSC. EM CiNiRATO

9、R VTVM connected to TP#2 and scope connected to L or R tape output SAME SAME SAME VTVM connected to TP#2; scope and distortion analyzer connected to L or R tape output See note * at bottom of page Scope connected to L or R tape output VTVM connected to TP#1; scope and distortion analyzer connected t

10、o L or R tape output ADJUST I00K POT TOt PHASING OF THE DISPLAY ON THE SCOPE FM ALIGNMENT ADJUST TEST LIMITS REMARKS 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 ligh

11、t adjust maximum CW. Top (secondary) and bottom (primary) of Tl, T2, T3 Maximum pos sible negative voltage Shunt to ground the winding not being adjusted. Do this with a .01 MFD capacitor in series with a IK resistor. Attenuate signal generator until output voltage at TP#1 is less than 1.5 volts wit

12、h one IF trans former winding shunted. IF transformers have terminal #1 marked with a green dot and are numbered clockwise. Primary and secondary of T4 Maximum pos sible negative voltage (should be 20 to 30 volts) Muting pot. MUST be maximum CW. Secondary (top) of T-5 Adjust for 0 volts The primary

13、(bottom) of T-5 should be adjusted only if a distortion analyzer is available. C-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-l, L-2,

14、 L3 SAME Repeat steps 6 and 7 until output is as high as possible. Primary (bottom) of T-5 0.5% distortion or less Use a strong signal from the FM generator. Adjust T-5 primary for minimum distortion. IF A DISTORTION ANALYZER IS NOT AVAILABLE, OMIT THIS STEP. DO NOT ADJUST T-5 PRIMARY. L-2, C-3 Mini

15、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 90MC) and L-3 (at 105MC) for minimum tilt. Check tilt again at 100MC. Muting t

16、hreshold 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 3% total noise and distortion Step 11 is an overall sensitivity chec

17、k. It requires a distortion analyzer and FM signal generator with attenuator. With 2.5 microvolts input at the 300 ohm terminals, TP#1 voltage should be .45 volts or more. 3 MAC 1500 MULTIPLEX STEPS TUNER DIAL SETTING SIGNAL GENERATOR INDICATOR FREQ. COUPLING MODULATION TYPE CONNECTED TO 1 Point of

18、no interference or signal Audio gener ator set to 67KC 0.5 volts out put or less TP#2 Audio VTVM L or R tape output z SAME MPX generator with 19KC pilot attenuated to approx. 5% level. (5% level is V2 of normal 10% level). 19KC pilot MUST be at tenuated for correct align ment SAME DC VTVM Pin 9 of 6

19、EA8 L. 3 100MC 100MC modu lated by MPX generator. 19KC pilot at normal output 300 ohm antenna termi nals with matching net work. (See * previous page) 1KC 100% modu lation (34KC deviation) modu lating left or right only Audio VTVM Pin 1 or 2 of T-7 4 SAME SAME SAME SAME Audio VTVM and scope L or R t

20、ape output 5 SAME SAME SAME SAME SAME SAME 6 SAME SAME SAME SAME SAME SAME 7 SAME SAME SAME Turn off 1 KC audio modulation SAME SAME 8 SAME Tune to a strong mono FM station SAME MPX stereo indi cator light on receiver 4 DECODER ALIGNMENT ADJUST TEST LIMITS REMARKS 67KC Trap (L-6) Adjust for mini mum

21、 voltage Stereo light must be on. This is done by adjusting the MPX Light Adj. control, R-l 2. 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 scope display 1. Turn off 19KC pilot on

22、 MPX generator. 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 or more Modulate left channel and measure right channel output. Adjust L-5 for minimum righ

23、t 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 sho

24、uld be at least 40db below modulated output. MPX light adjust control R-l 2 Turn control until light comes on. Then back off just enough to cause the light to go off. Then back off about Va of a turn more. Light should operate ONLY on a MPX signal. 5 PREAMP/AMP TESTS AND ADJUSTMENTS All adjustments

25、should be made after a minimum of a 10 minute warm-up. 1 Remove the 12AX7 (V-9). 2 Measure the voltage at TP#3. Voltage should be 0.7 volts positive. If it is not 0.7 volts, ad just R-8. 3 Do likewise with TP#4 and R-9, TP#5 and R-10, TP#6 and R-l 1. 4 Re-insert the 12AX7. 5 Feed a 1 KC signal into

26、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 oscillate. If channels are un balanced, adjust R-55. This control is found on the left preamp printec, circuit board. It will

27、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 adjus

28、t 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

29、output. 8 MAC 1500 PARTS LIST TUBES ITEM NO. USE TUBE NUMBER PART NUMBER V-l RF Amplifier 6DS4 165-013 V-2 Mixer 6DS4 165-013 V-3 1st IF Amplifier 6AU6 165-004 V-4 2nd IF Amplier 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 Ampli

30、fier, Indicator Control 6EA8 165-044 V-8 MPX 38KC Oscillator 12AU7 165-018 V 9 Voltage Amplifier 12AX7 165-019 V-10 Left Channel Driver 12AU7 165-018 V-ll Right Channel Driver 12AU7 165-018 V-12 Left Channel Output 7591 165-022 V-13 Left Channel Output 7591 165-022 V-l 4 Right Channel Output 7591 16

31、5-022 V-l 5 Right Channel Output 7591 165-022 ITEM NO. TRANSISTORS USE TRANSISTOR NUMBER PART NUMBER Q-l Local Oscillator TA2556/40244 132-008 Q-2 Control Amplier 2N3638 132-007 Q-3 MPX Lamp Control 132-010 Q-4 Oscillator On-Off Control 2N3391A 132-004 Q-5 Left Channel Audio Amplifier 2N3391A 132-00

32、4 Q-6 Right Channel Audio Amplifier 2N3391A 132-004 Q-7 Left Channel Audio Amplier 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-l 1 Left Channel Emitter Follower 2N3391A

33、 132-004 Q-l 2 Right Channel Emitter Follower 2N3391A 132-004 Q-l 3 Left Channel Low Level Amplifier 2N720A 132-002 Q-l 4 Right Channel Low Level Amplifier 2N720A 132-002 Q-l 5 Left Channel Emitter Follower 2N3391A 132-004 Q-l 6 Right Channel Emitter Follower 2N3391A 132-004 Q-l 7 Left Channel Emitt

34、er Follower 2N3391A 132-004 Q-l 8 Right Channel Emitter Follower 2N3391A 132-004 Q-l 9 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-l Diode FD100 070-022 D-2 Diode FD100 070-022 D-3 Diode FD10

35、0 070-022 D-4 Diode FD100 070-022 D-5 Diode FD100 070-022 D-6 Diode (Matched pair 1 N542) IN542 070-003 D-7 Diode (Matched pair 1N542) IN542 070-003 D-8 Diode (Matched pair 1 N542) IN542 070-003 D-9 Diode (Matched pair 1N542) IN542 070-003 D-10 Diode (Matched pair 1 N542) 070-003 D-l 1 800 PIV 750MA

36、 Silicon Rectifier 070-017 D-l 2 600 PIV 750MA Silicon Rectifier 070-016 D-l 3 600 PIV 750MA Silicon Rectifier 070-016 D-l 4 800 PIV 750MA Silicon Rectifier 070-017 D-l 5 400 PIV 750MA Silicon Rectifier 070-015 D-l 6 10 V 400 MW Zener Rectifier 070-011 CONTROLS ITEM PART NO. FUNCTION RESISTANCE NUMB

37、ER R-1 Balance Control 500K-500K 134-165 R-2 Ba$s Control 1M-1M 134-117 R-3 Treble Control 500K-500K 134-118 R-4 Volume Control 60K-60K 134-164 R-5 Muting Adjust Control 100K 134-102 R-6 Driver Balance Control 5K 134-103 R-7 Driver Balance Control 5K 134-103 R-8 Bias Adjust Control 100K 134-102 R-9

38、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 t SWITCHES ITEM PART NO. FUNCTION DESCRIPTION NUMBER S-l Rotary Switch Input Selector 146-096 SS-26 19/32

39、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 (5 used) Stereo/Mono, Tape Monitor, LF and HF Filters, Loudness. 148-007 TRANSFORMERS ITEM PART NO. FUNCTION NUMBER T-l FM-IF 162-005 T-2 FM-IF 162-004 T-3 FM-IF 162-004

40、 T-4 IF (Muting) 162-029 T-5 FM Discriminator 162-027 T-6 19KC Amplifier 162-010 T-7 38KC Oscillator 162-009 T-8 Baiun 076-006 T-9 Output (Left) 159-062 T-10 Output (Right) 159-062 T-l 1 Power 159-061 CAPACITORS ITEM PART NO. DESCRIPTION CAPACITANCE TOLERANCE NUMBER C-l Variable FM 059-006 C-2 Trimm

41、er (Ceramic) 1-8 PF 060-001 C-3 Trimmer (Ceramic) 1-8 PF 060-001 C-4 Trimmer (Glass) 060-002 C-5 Ceramic Disc. .005MFD +80-20% 061-040 C-6 Ceramic Disc. .001 MFD 061-035 C-7 Ceramic Disc. .001 MFD 061-035 C-8 Ceramic Feed-Thru .001 MFD 061-036 C-9 Ceramic Feed-Thru .001MFD 061-036 C-10 Ceramic Disc.

42、 10PF 20% NPO 061-009 c-u Ceramic Tubular 5PF .25PF N150 061-005 C-l 3 Ceramic Disc. .005 +80-20% 061-040 C-l 6 Ceramic Disc. I0PF 20% NPO 061-009 C-l 7 Ceramic Tubular 3PF .25PF 061-003 C-l 8 Ceramic Disc. 10PF 20% NPO 061-009 C-l 9 Ceramic Feed-Thru .001 MFD 061-036 C-20 Ceramic Feed-Thru .001 MFD

43、 061-036 C-21 Ceramic Feed-Thru .001 MFD 061-036 C-22 Ceramic Disc. .005MFD +80-20% 061-040 C-23 Ceramic Disc. 10PF 20% NPO 061-009 C-24 Ceramic Disc. .005MFD +80-20% 061-040 C-27 Ceramic Feed-Thru .001MFD 061-036 C-28 Ceramic Feed-Thru .001 MFD 061-036 C-29 Ceramic Disc. 005MFD +8020% 061-040 C-30

44、Ceramic Disc. 01MFD +80-20% 061-043 10 CAPACITORS ITEM NO. DESCRIPTION CAPACITANCE VOLTAGE TOLERANCE PART NUMBER C-31 Ceramic Disc. 12PF 20% NPO 061-010 C-32 Ceramic Disc. .1MPD +80-20% 061-049 C-33 Ceramic Disc. .005MFD +80-20% 061-040 C-34 Ceramic Disc. .005MFD +80-20% 061-040 C-35 Ceramic Disc. 0

45、1MFD +8020% 061-043 C-36 Ceramic Tubular 15PF .75PF 061-012 N150 C-37 Flat Foil .IMFD 40V 20% 064-027 C-38 Ceramic Feed-Thru .001 MFD 061-036 C-40 Ceramic Feed-Thru 001MFD 061-036 C-41 Ceramic Feed-Thru .001 MFD 061-036 C-42 Ceramic Feed-Thru .001 MFD 061-036 C-43 Ceramic Disc. . 1MFD +80-20% 061-04

46、9 C-44 Ceramic Disc. 005MFD +80-20% 061-040 C-45 Ceramic Disc. .005MFD +80-20% 061-040 C-46 Ceramic Disc. 6.8PF 20% NPO 061-008 C-47 Ceramic Disc. 12PF 20% NPO 061-010 C-48 Ceramic Disc. 47PF 20% N470 061-019 C-49 CeramicFeed-Thru 100PF 20% 061-021 C-50 Ceramic Disc. .02MFD +80-20% 061-045 C-51 Silv

47、er Mica .0027MFD 100 V 5% 063-004 C-52 Ceramic Disc. 100PF 10% N1500 061-023 C-53 Ceramic Disc. .001 MFD 061-035 C-54 Ceramic Disc. .001 MFD 061-035 C-55 Ceramic Disc. .02MFD +80-20% 061-045 C-56 Silver Mica 0012MFD 100 V 5% 063-002 C-57 Silver Mica 0012MFD 100 V 5% 061-002 C-58 Electrolytic 100MFD

48、3V 066-047 C-59 Ceramic Disc. .1MFD +80-20% 061-049 C-60 Ceramic Disc. 220PF 20% 061-028 C-61 Silver Mica .0047MFD 5% 063-005 C-62 Silver Mica .0047MFD 5% 063-005 C-63 Ceramic Disc. .005MFD +80-20% 061-040 C-64 Ceramic Disc. .005MFD +80-20% 061-040 C-65 Ceramic Disc. 005MFD +80-20% 061-040 C-66 Ceramic Disc. .005MFD +80-20% 061-040 C-67 Ceramic Disc. 330PF 10% 061-029 C-68 Ceramic Disc. 330PF 10% 061-029 C-69 Ceramic Tubular 430PF 5% 0