McIntosh MX113 Operating and installation instructions

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McIntosh
MX 113
AM/FM TUNER PREAMP
SERVICE INFORMATION
STARTING WITH SERIAL NO. 100H1
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McIntosh laboratory inc. 2 chambers street binghamton, new york
MX
113

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MX 113
SENSITIVITY
75pV IHF (external ant.)
ELECTRICAL SPECIFICATIONS
AM TUNER SECTION
SELECTIVITY, ADJACENT CHANNEL
35 dB minimum IHF in "NORMAL" Position.
1+5 dB minimum IHF in "NARROW" Position.
SIGNAL TO NOISE RATIO
1+5 dB IHF minimum; 55 dB at 100% modulation.
HARMONIC DISTORTION
Does not exceed 1% at 30% modulation.
IMAGE REJECTION
65 dB minimum 5^+0 kHz - 1600 kHz.
FREQUENCY RESPONSE
3.5 kHz - 6 dB, "NORMAL" Position.
2.1 kHz - 6 dB, "NARROW" Position.
FM TUNER SECT ON
USEABLE SENSITIVITY
2.5 microvolts at 100% modulation (+75 kHz
deviation) for 3% total noise and harmonic
distortion IHF.
S IGNAL TO NOISE RAT 10
70 dB below 100% modulation.
CAPTURE RAT 10
1 .5 dB
HARMONIC DISTORTION
Mono: Does not exceed 0.3% at 100%
modulation j+75 kHz deviation.
Stereo: Does not exceed 0.5%
AUDIO FREQUENCY RESPONSE
_+l dB 20 Hz to 15,000 Hz with standard
de-emphasis (75 psec.) and 19,000 Hz
pilot filter.
SELECTIVITY
ADJACENT CHANNEL:
6 dB minimum IHF in "NORMAL" Position.
15 dB minimum IHF in "NARROW" Position.
ALTERNATE CHANNEL:
58 dB minimum IHF in "NORMAL" Position.
88 dB minimum IHF in "NARROW" Position.
SPURIOUS REJECTION
90 dB IHF minimum.
IMAGE REJECTION
95 dB minimum, 88 MHz - 108 MHz.
STEREO SEPARAT ION
35 dB at I,000 Hz.
SCA FILTER
50 dB rejection from 67 kHz to Ik kHz.
275 dB per octave slope.
PREAMPLIFIER SECTION
FREQUENCY RESPONSE
+0.5 dB, 20 Hz to 20,000 Hz.
DISTORTION
Less than 0.1% at 2.5 volts 20Hz to 20 kHz.
INPUT SENSITIVITY (phono 1 and phono 2)
2 millivolts for 2.5 volts output at 1 kHz.
OUTPUT (tape)
0.25 volts with rated input. Phono input
signal of 10 millivolts produces 1.2 volts
output. FM and AM will produce 1.2 volts
output at 100% modulation.
OUTPUT (center channel)
2 volts with rated input to both channels.
BASS CONTROL
INPUT SENSITIVITY (aux, tape)
0.25 volts for 2.5 volts output.
-18 dB to +16 dB at 20 Hz.
TREBLE CONTROL
HUM AND NOISE (phono 1 and phono 2)
72 dB below 10 millivolt input.
+20 dB to 20,000 Hz.
LF FILTER
HUM AND NOISE (aux, tape)
85 dB below rated output.
OUTPUT (main)
2.5 volts with rated input. Up to 10
volts can be developed without distor¬
tion. FM and AM will produce up to 10
volts output at 100% modulation.
Flat or roll off below 50 Hz, down 12 dB
at 20 Hz.
HF FILTER
Flat or roll off above 5000 Hz, down 12 dB
at 20,000 Hz.

MX 113
SCHEMATIC NOTES
1. Unless otherwise specified: Resistance values are in ohms, 1/4 watt, and 10%
tolerance; capacitance values smaller than 1 are in microfarads (pF); capacitance
values greater than 1 are in picofarads (pF); inductors are in microhenries (pH).
?•
3.
4.
5.
6 .
b.
c.
d.
Printed circuit board components are outlined on the schematics by dotted lines.
The circled numbers around the dotted lines correspond to the numbers on the PC
Board layouts.
The heavy lines on the schematics denote the primary signal path.
The terminal numbering of rotary switches is for reference only.
All voltages indicated on the schematics are measured under the following conditions:
a. Use of an 11 megohm input impedance VTVM.
All voltages +10% with respect to chassis ground.
No signal at input or antenna terminals.
AC input at 120 volts, 50/60 Hz.
Front panel controls at:
Tuning indicator 100 MHz (no signal)
Fully CCW
Stereo
Out
AM (to measure AM section)
FM (to measure FM section)
Panel Lights Bright
Selectivity Out
f. Voltages shown in rectangles are measured with selectivity switch in the
"In" position.
In units with serial no.'s below 187H5 R219 and R225 are used.
Volume
Mode
Muting
Input Selector
7. In units with serial no.'s below 190H0 R329 and R330 are 15K; C8 js 12pF
R528 is used; D505 and D506 are not used and R530 is connected as shown by dotted
line.
8. In units with serial no.'s below 178H9 C38 is 3pF; C527 and C528 are not used and
dial glass is McIntosh part no. 044-359.
9. In units with serial no.'s below 189H4 C505 is .02pF.
10. In units with serial no.'s from 175HO to 190H0 C527 and D504 are used.
11. In units with serial no.'s below 199H9 C124 is used and C402 is lOOpF.
12. In units with serial no.'s from 167H5 to 178H8 C101 and C108 is not used.
13. In units with serial no.'s below 182H5 R408 is 680fi; R411 is 10K; R412 and R418 are
used.
14. In units with serial no.'s from 238H2 to 282H6 C213 is used. In units with serial no.'s
below 282H6 R203 is used and L201 is not used.
15. In units with serial no.'s below 322H6 R337 and R338 is 1.8k.
16. In units with serial no.'s below 269H6 the MPX Lamp is a #1828 bulb and r 419 is used.
17. In units with serial no.'s below 262H1 C214 is not used.
18. In units with serial no.'s below 400H 1 : R399 and R400 are 1M; C303, C304, C3 1 3 & C3 i 4 are
used; C346, C347, C348, C349, C350, C351, R399-2 and R399-3 are not used and c4 1 5 is ,22pF.
19. In units with serial no.'s below 282H6: C413 is .lpF; R415 and R416 are used; Q407 is not
used and D407 is connected as shown by dotted lines.
20. In units with serial no.'s below 334H9 R530 is 7.5k and D505 is McIntosh Part No. 070047.
21. In early units R526 is not used.
22. In early units CIO and C35 are .OOlpF.

TUNING
CONDENSER
DRUM
113
(TO
IDLER
PULLEY
AND
TUNING
SHAFT)
BLACK

MX 113

R F CHASSIS
IF PC BOARD 044-277
/-NOTE 12
RI06

IF OUT
TO
PREAMP
SECTION
TUNER SECTION
154-647

LEFT
CHANNEL
INPUTS
TAPE <
AUX. (
TAPE OUT (
RIGHT
CHANNEL
INPUTS
TAPE (
AUX. <
TAPE OUT (
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LEFT CHANNEL PREAMP. PRINTED CIRCUIT BOARD 044-554

MX 113
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TO PIN 5 S30I- I REAR
<FM SECTION)
IN -NARROW

MX 113
MPX PC BOARD 044-299

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R407
25K
I MUTING APJI
-I.5V JL GRY/WHT
- (|4>-
MPX PC BOARD 044-299
C409
FROM FM OUTPUT
OF TUNER SECTION
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R404
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R414
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100
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22 K
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R413
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