McIntosh C27 Preamp Service Information.pdf

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1、ltMntosb C 27 PREAMPLIFIER SERVICE INFORMATION STARTING WITH SERIAL NO. BV1001 McIntosh laboratory inc. Binghamton, new york 13903 39-032 C 2 7 PERFORMANCE LIMITS FREQUENCY RESPONSE +0 -0.5 dB 20Hz to 20,000 Hz DISTORTION Will not exceed 0.05% at rated output level, 20 Hz to 20,000 Hz. INPUT SENSITI

2、VITY AND IMPEDANCE AUXILIARY 1 and 2, TUNER,TAPE 1 and 2: 250 millivolts at 100 000 ohms PHONO 1 and 2: 2 millivolts at 47K ohms and lOOpF HUM AND NOISE AUXILIARY 1 and 2, TUNER, TAPE 1 and 2: 85 dB unweighted; 90 dB 1HF A weighted. PHONO 1 and 2; 80 dB beiow 10 mV input, un weighted; 85 dB 1HF A we

3、ighted. OUTPUT LEVEL AND IMPEDANCE MAIN OUTPUT 2.5 volts with rated input, less than IK ohms source impedance, to operate into 22K ohms load or higher. Maximum out put is greater than 10 volts. TAPE OUTPUT 0.25 volts with rated input, less than 1.5K ohms source impedance, to operate into 22K ohms lo

4、ad or higher. Maximum output is greater than 10 volts. CENTER CHANNEL OUTPUT (L+R) 2.5 volts with rated input to both channels, less than 1.2K ohms source impedance, to operate into 22K ohms load or higher. VOLTAGE AMPLIFICATION IN DECIBELS AUXILIARLY I and 2, TUNER, TAPE 1 and 2 to MAIN OUTPUT 20 d

5、B, to TAPE OUTPUT 0 dB PHONO 1 and 2 to MAIN OUTPUT 62 dB, to TAPE OUTPUT 42 dB POWER REQUIREMENT 120 volts, 50/60 Hz, 15 watts MECHANICAL INFORMATION SIZE: Front panel measures 16 inches wide (40.64 cm) by 5-7/16 inches high (13.81 cm). Chassis measures 15 inches wide (38.1 cm) by 5 inches high (12

6、.7 cm) by 13 inches deep (33.02 cm), including PANL0C shelf and back panel connectors. Knob clearance re quired is 1-1/2 inches (3.81 cm) in front of the mounting panel. FINISH: Front panel is anodized gold and black with special McIntosh gold/teal panel nomen clature illumination. Chassis is black

7、MOUNTING: Exclusive McIntosh developed profes sional PANL0C. WEIGHT: 18 pounds (8.2 kg) net, 33 pounds (15.0 kg) in shipping carton RIGHT CHANNEL-1 (-LEFT CHANNEL INPUTS-1 OUTPUTS OUTPUTS I-INPUTS GAIN = 14 dB AUX 1 AUX 2 TUNER PH 1 PH 2 TAPE 1 TAPE 2 TAPE 1 TAPE 2 TAPE 2 TAPE 1 TAPE 2 TAPE 1 PH 2 P

8、H 1 TUNER AUX 2 AUX 1 GAIN = 14 dB C 2 7 N = 14 dB GAIN = 6 dB HEADPHONE JACK BLOCK DIAGRAM C 2 7 TUNER TUNER YEL. _ LEFT LEFT TAPE 2 IN 1? LEFT V TAPE I OUT BRN/GRYI left TV1 MAIN OUTPUT OT YTo TioJ RIGHT nRED/GRY y TAPE 2 OUT MAIN OUTPUT ) . f/O RIGHT T2-*TI y- YFi Qi, TAPE 2 OUT “PY LED JbV- PUSH

9、 BUTTON SWITCH 0TO4V iRsht 045246 ti-t2 qyorn O TAPE I OUT 400 SER1ES symbol NOS C0#Y LED L-/O TO 4V T RIGHT T2,CRED TAPE 2 IN MONITOR LEO fo 2V 2thn M0NIT0BLpi2)|!i_ 2 0ND 0“ GS7- D/GRY/7* RIGHT Z-TAp -StK/?GND TUNER IN RIGHT AUX 2 OUT lux 2 INPUT 045-247 300 SERIES SYMBOL NOS AUX 1 IN Q 19 Pv I CU

10、RRENT k7Nv SUPPLYk_y 2 TO 6V T2 MONITOR INDICATOR XLE0 045-243 , 500 SERIES SYMBOL NOS SECTION 2 FRONT V V_ RIGHT blu/wht/phono OUTPUT INTERCONNECT LEFT CHANNEL 045-250 100 SERIES SYMBOL NOS RIGHT CHANNEL 045-250 100 SERIES SYMBOL NOS 7 SECTION I SCHEMATIC NOTES C 2 7 1. Unless otherwise specified:

11、Resistance values are in ohms, 1/4 watt, and 5% tolerance; capacitance values smaller than 1 are in microfarads (pF); capacitance values greater than 1 are in picofarads (pF): inductors are in microhenries (pH). 2. Printed circuit board components are outlined on the schematics by dotted lines. The

12、circled numbers around the dotted lines correspond to the numbers on the PC Board layouts. 3. The heavy lines on the schematics denote the left channel primary signal path. The heavy dash lines on the schematics denote the right channel primary signal path. 4. The terminal numbering of rotary switch

13、es is for reference only. 5. All voltages indicated on the schematics are measured under the following conditions: a. Use of an 11 megohm input impedance VTVM. b. All voltages +10% with respect to chassis ground. c. No signal at input terminals. d. AC input at 120 volts, 50/60 Hz. e. Front panel con

14、trols at: Speaker Off F i 1 ter Out Input Selector Phono 1 Mode Selector S tereo T reb1e Flat Bass Flat Vo 1ume ccw Balance Center Detent Loudness Flat Push Switches Out Power Switch On All other controls at normal positions R 203 . -wv g CJ C206 B i *7 r R207 -r C AAAr 0202 R211 R2I0 AW AW * R2!s/W

15、VS_L ft I 2iAAr * WV-o 0205 wv R 209 |C s AAV, 6 R102 5 o AW AW AW- AW Aw _icji6 AAA/- AW AAAr 71 Rl 18 Rl 10 RII2 -)i- -)h -)h -L0-“6- AAAr AAAr A? AAAr AAAr R 146 AAV CI2_3|_ R Id. Q * AAAr AAAf -)h5 R19 Rl 28 R22 CII0 _ 1 0 5 AAA- gir AAV R144 AAAr AAAr Q/-We RI78RI3S R,4 R|84 CV AAA AAA?1 A RI62

16、 cAe AAA?182 - - o A/W - AAV AAV -412. R89 R127 R12 I rinq c|23 ml, | 0h AAV_ CI|9 -V *-d6-=r /; vw AT wv RI43 o AAt AAAr Q,lir-W E RI77RI35 R39r)83 RI45 ciyTE -ww AAAr AAV r,g7B QM5.- p jvaa!81 AW Cl0| AAV 5 Xise FI- . A RIB0 , Rl6 |5VV -l48 AAV 0 E Rl8X8 Tfg AAAr QII3 RI7 c-O-e AW V iCI45 RIT6. A

17、A 040 042 -AAV )r768 Fhl72VVV AW AW Rl7 AAAr -)| R166 ra AVr RI5W c-Q-e wv Cl 29 l VW 2 Y -45 ) “AAAr 5 R185 71 09 |RI5? -)-47 ul_ 3=r 4=3 -)h ./WV 8241=TT“ ! 7 r|5| 039 041 AAAr AAVri53 -)ta67 )1 ritIAAt AAV AW AWR69 )| AAAr Fb 033 Rl65 CI43 oooooooooooo 25 24 23 22 21 20 19 18 17 16 15 14 42 41 40

18、 0 O O 37 36 35 34 33 32 31 30 29 28 27 26 oooooooooooo 25 24 23 22 21 20 19 18 17 16 15 14 oooooooooooo H=3h D20I RJ50J- o C130 -(- HRI70 C142 - | R176 I o Hr74 y CI48 Emu- ci46 B. I- aqI14 c“(he 50116 r“v - QII6 -jRI88 |r 14 5 h C139 Cl 4 H R17 5 f O j R17 3 CI47_ -sQH5 -iRI87 j h -RTeTI =Pll -1 I

19、D- 0 R207J- Q202 C206 I SF0 -IRI28 I- 1r| 22h o Uj uj* 6 iiJT o f. O I Rl! 4 l31 0 Cl 04 - |rI27 - f RI2I | RI3 I _ jO q Tjij TuJO tuj _ a (Rt 13 U c Q 00 S 0 C mni loi .a I In 1 in 1 (111. f I 0: I ml? I i I m i m li I m i O |RI02 W jR125 I- o o -TrizsI 4 3 MAIN PC BOARD 045250 C 2 7 MAIN 330 K C 2

20、 7 PUSHBUTTON SWITCH C 2 7 o4 -l5325h d. 0* -|R3Q7h -lR3M SI u P I ; - ft E Q ? 7 C301 O * C303Q 1 C305Q Jf 3 AAV R3IS C305 r if AAV f .RfejlCfJ. C303 6 if AA/V 04 LEFT INPUT TERMINAL PC BOARD 045-247 40 Hsasihj, Ol -|R308h X 02 -TRTm- 1 S 03 cvjI o 6 Isl 6 to! 1- c Q C302Q 1 C304Q T c3oe(_) r 50 .A

21、AV Z0 I AAV *0 1 AAV 0 o R3I2 R308 N R304 to C306 7 -It C304 6 -It fO C3025 it RIGHT INPUT TERMINAL PC BOARD 045-247 0)5 o4 03 o2 : 0* FRONT PANEL & TRIM McIntosh Laboratory, Inc. Customer Service Department F ront Panle Glass 016-165 2 Chambers Street End Caps 018-160 Binghamton, New York 13903 (te

22、lephone 607-723-3512) Knob - Volume 090-017 CAPAC1 TORS Knob - Mode 090-156 Symbo1 Part Knob - Input 090-156 Number Description Number Knob - Filters 090-200 C9 Elect. 10pF 50V 066-221 Knob - Speakers 090-201 C 1 3 Elect. 80/80/150/150pF 066-095 Knob - Loudness 090-186 DIODES Knob - Balance 090-187

23、D1,2 Si. Signa1 diode 070-031 Knob - Bass Right 090-200 D3 Si. Signa1 Diode 070-031 Knob - Bass Left 090-201 D20 1 Zener 75V 070-025 Knob - T reb1e Right 090-200 D501,502 LED Lamp 070-093 Knob - Treble Left 090-201 D503.504 LED Lamp 070-093 D505 LED Lamp 070-093 FUSES MlSCELLANE0US FI Fuse 0.5A Norm

24、 Bio 089-009 Sh i pp ing Carton 045-338 TRANS 1ST0RS Mounting Temp #100 038-178 Q101,102 S i . PNP Transistor 132-176 Hardware Package 045-142 Ql03,104 S i . NPN Transistor 132-175 Fuseholder 178-099 Q105,106 S i . NPN Transis tor 132-175 L i ne Cord 170-019 801Z010 S i . NPN Transistor 132-175 Audi

25、o Cab 1 e 170-015 Q1 09, 110 $ i . PNP Transistor 132-176 Owners Manual 039-033 Ql 1 1 , 1 12 S i . NPN Transistor 132-175 Short ing Phono Plug 127-021 Ql 13, 1 14 Si. NPN Transistor 132-175 Ql15, 116 S i . NPN Transistor 132-175 Q20 1 NPN Power Transistor 132-028 Q202 Si NPN Transistor 132-175 POTE

26、NTIOMETERS R3 Volume Control 134-319 R4,5 Ba1./Loudness Control 134-320 SWITCHES SI Input Selector 146-193 S 2 Mode Selector 146-196 S3 LF-HF Filter 146-194 S4 Bass Switch 146-195 S5 Treb1e Switch 146-195 S6 Speaker Filter Switch 146-194 S401 Pushbutton Switch 150-026 039-032 20C1028S7-M7032-1 S.B.

27、No SERVICE BULLETIN REDUCE RFI & ELIMINATE OSCILLATION MODEL: C 27 Preamplifier PURPOSE OF MODIFICATION: To reduce sensitivity to RF interference and to eliminate oscillation when using a moving coil phono cartridge. WHEN MODIFICATION SHOULD BE MADE: Whenever customer is complaining of: A. Undersire

28、d reception of CB, ham apparatus and man made noise in the phono mode. B. Oscillations, when a moving coil cartridge is used. PARTS REQUIRED: QUANTITY PART NUMBER DESCR1PTI0N 2 061 1039 Disc. cap. .003pF, Cl 03, 104 20% 2 14 1090 Film res. 56k, 5%, 1 / 4w 4 141 1041 Film res. 470ft, 5%, 1 / 4w PROCE

29、DURE: All changes are on the main PC board (045250), except step 4. 1. Change C103 and C104 from 470pF 10% to .003pF 20% 2. Remove and replace R115 and R116, 120ft, 5%, 1/4W with wire jumpers. 3. Locate capacitor C109, Disconnect the lead on C109 that connects to R121. Connect a 56, 5%, 1/4w resisto

30、r in series with the disconnected C109 lead and the circuit board where the C109 lead formerly connected. Do likewise for capacitor C110. 4. Connect right at the phono jacks a film resistor = 470ft, 5%, 1/4W in series with the leads connected to these phono jacks. (OVER) Mrlntnsh lahnratorv Incorporated 2 Chambers Street Binghamton, New York 13903 Phone: Area Code 607-723-3512 039-105