McIntosh MC-2105 Service manual

FROM SERIAL

MclNTOSH LABORATORY INC. 2 CHAMBERS STREET BINGHAMTON, NEW YORK

NO.

10M01

TO

26M07

MC

2105

ELECTRICAL SPECIFICATIONS

POWER OUTPUT:

105 RMS watts continuous per channel into 4, 8, or 16 ohms both channels operating.

HARMONIC DISTORTION:

Less than 0.25% at 105 watts power output from 20 Hz to 20 kHz, both channels operating. Typical performance is less than 0.1% at rated power. Distortion decreases as output

is reduced.

INTERMODULATION DISTORTION:

Less than 0.25% if instantaneous peak power output is 210 watts or less per channel with both channels operating for any combination of frequencies 20 Hz to 20 kHz.

FREQUENCY RANGE:

20 Hz to 20 kHz +0, -0.1 dB at rated power. 15 Hz to 60 kHz +0, -0.5 dB at rated power. 10 Hz to 100 kHz +0, -3.0 dB at rated power.

NOISE AND HUM:

90 dB or more below rated output.

OUTPUT IMPEDANCE:

4, 8, and 16 ohms

OUTPUT VOLTAGES:

25 volts (connect to 8 ohm outputs.)

DAMPING FACTOR:

18 at 4 ohms output 13 at 3 ohms output 10 at 16 ohms output

INPUT IMPEDANCE:

200,000 ohms

INPUT SENSITIVITY:

0.5 volts. Level control provided for higher input voltage.

POWER REQUIREMENTS:

117 volts AC 50-60 Hz, 90 watts at zero signal output, 450

watts at rated output.

INPUT SECTION PRINTED CIRCUIT

BOARD

043-795

LOCATION OF TRANSISTORS NOT ON PRINTED CIRCUIT BOARDS

INPUT

SECTION PRINTED CIRCUIT BOARD

043-795

HEAVY LINE SHOWS PRIMARY SIGNAL PATH

INPUT SECTION

MC

2I05

154-292

LEFT CHANNEL

POWER OUTPUT SECTION PRINTED CIRCUIT BOARD

043-805

RIGHT CHANNEL

POWER OUTPUT SECTION PRINTED CIRCUIT BOARD

043-805

OUTPUT

POWER

366

154-

SECTION

2105

MC

METER SECTION PRINTED CIRCUIT BOARD

METER SECTION

MC

2105

154-294

SCHEMATIC NOTES

1. Unless otherwise specified: Resistance values are in ohms, 1/2 watt, and 10% tolerance; capacitance values smaller than 1 are in microfarads (µf) ; capacitance values greater than 1 are in picofarads (pF); inductors are in microhenries (µH).

2.

Printed

I 3. The heavy lines on the schematics denote the primary signal path.

4. The terminal numbering of rotary switches is for reference only.

5. All voltages indicated on the schematics are measured under the following conditions:

6. R125, R126, R127, and R128 are 2.7K in early units.

7. R215 and R216 are 1.2K and R217 and R218 are 22K in early units.

8. In

9. In

10.

C125

11. R137f R138, R141, and Rl42 are 75ohm 9W 10% (part No. 139-070) and R119 and R120 are 2751

12. In

13. In

14.

R155

15.

R109,

16. In No's from 10M40 to 23M25, C117 and Cll8 are not used.

17. In

circuit

circled

a. Use of an 11 megohm impedance VTVM. b. All voltages ±10% with respect to chassis ground. c. Ho signal at input terminals. d. AC input at 117 volts AC, 50/60Hz. e. Front panel controls at:

C109. and C110 (part No. 064-044) are .047; The emitter of Q113 and Q114 is connected as shown

R147, R148, R149, and R150 are .15W (part Ho. 139-055); pins Ho. 12 and 9 on PC boards are

in early units.

(part No. 076-010) are not used.

connected

numbers

Left Gain

Meter Range

Right Gain Speakers Power

units

with

by the

units with

connected

and

units

with

units

and

R156

110 is 47K in

units

with

units

with

dotted

C126

with

as

board

on the

serial

as

shown

are

serial

shown

are

8.2ohm

serial

components

dotted

FULLY CCW

OFF

FULLY CCW

ON

OH

No's below

line;

R139

No's below 11M93: Rl59

by

used

in

No's below

No's

by

below

dotted

10% in

units

with

No' a

below

No's below

lines

and

dotted

units

line.

serial

are

outlined

correspond

10M40:

Rl40 {part

line.

with

20M01;

20M50

units

10M40;

23M25,

serial

R107, R108, C105,

R161

with No's

C117

C115

on the

C111, C112, C113,

and

No's

and

serial

from

and

to the

Ho.

139-061)

R160

from

R162

No's

11M93

Cll8

C116

schematics

numbers

are not

11M93

are not

from

to

are

by

dotted

on the PC

and

C114,

are

used.

used; R143, R144, R145, R146,

to

13M05.

and

C106

are

used

and pin l4 is

l0M40

to

21M13.

23M25.

.0012.

In

lines.

board

are

used; C107, C108,

used;

units

layouts.

ferrite

with

The

aerial

beads

18. Adjust meter calibration controls R213 (left channel) and R214 (right channel) so output meters indicate +3dB when meter range switch is in the "0" position and the amplifier is delivering 105 watts output.

METER SECTION PRINTED CIRCUIT BOARD 043-711

REPLACEMENT PARTS

All

parts

not

able

from

Replacement by PART NUMBER from:

Symbol

Number Description C1,2 Mylar ,22uF 250V C3,4 Mylar .47uF 250V C5,6 Elect. 500uF 16V C9,10 Elect. l0uF 25V NP C11,12 Elect. 100uF 15V C101,102 Elect. C121,122 Elect. 10uF 50V C201,202 Mylar ..47uF 250V C203,204 C301 Elect. 39,000uF 40V C302

Elect.

C303

Elect. 80/80/l50/50uF

D101,102 Si. signal diode D103,104 Si. reference diode Dl05,106 Si. signal diode D107,108 Si. signal diode D201,202 Ge. signal diode D203,204 Ge. signal diode D301,302 Rectifier Assy (Black) D303,304 Rectifier Assy (Red) D305

Si.

D306

Si.

P301 Fuse 5 ampere Slo-Blo

L101,102 Choke 75uH

M201,202 Meter (power level)

listed

radio

parts

Mclntosh Laboratory Inc.

Customer Service Department 2

Chambers

Binghamton, Hew York 13903

(telephone 607-723-3512)

Elect.

are

parts

may be

CAPACITORS

330uF

100uF

39,000uF

rectifier rectifier

common

jobbers.

obtained

Street

200/200/150/150V

DIODES

PUSES

CHOKES

METERS

items

3V

40V

when

obtain-

ordered

Part

Number

064-043 064-045

066-107 066-005 066-127 066-105 066-113 064-045

066-047 066-119 066-119 066-095

070-022

070-040

070-022

070-003

043-903

043-904

070-031

089-007

122-013

124-013

Q1,2 Q3,4 Q5,6

Q101,102 Q103,104

Q105,106

Q107,108 Q109,110

Q111,112 Q113,114

Q115,116

Q117,118

Q119,120

Q121,122

Q123,124

Q125,126

Q201,202

R1, 2

R213,2l4

R117,118 R137,138

R141,

142

R143,144 R145,146

R147,148 R149,150 R159-160 R301,302

- TRANSISTORS Si. NPN transistor Si. NPN transistor Si. PNP transistor Si. PNP transistor Si. PNP transistor Si. NPN transistor

Si. NPN transistor Si. PNP transistor Si. NPN transistor Si. PNP transistor Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

(Below

Serial

Si. NPN transistor

(Above

Serial

Si. NPN transistor

POTENTIOMETERS Gain controls Meter calibration adjust

Wirewound 3.6K 5% 5W Wirewound .56 ohms 5W Wirewound .56 ohms 5W Wirewound .33 ohms 5W Wirewound .33 ohms 5W Wirewound . 33 ohms 5W

Wirewound . 33 ohms 5W Wirewound .33 ohms 5W Thermistor

No.

RESISTORS

20M01)

132-054 132-054 132-031 132-031

132-031 132-515

132-021 132-032

132-038 132-039

132-518

132-541

132-518

132-541

132-517

132-541

132-517

132-541

132-517

132-542

132-517

132-542

132-054

134-191 134-120

139-065 139-061

139-061 139-071 139-071

139-071 139-071 139-071

144-012

31

S101 S201 S301

S302,303

SWITCHES Input coupling switch Speaker switch Meter range switch Power on-off switch Thermal cut-out

TRANSFORMERS

148-006 146-103

146-109 146-102

153-007

T101,102

T301

Front panel Front panel end caps

Knobs (all controls )

#1866 (for wording) #1888 (for meters)

Shelf bracket (right)

Shelf bracket (left) Mounting template #300 Hardware package

Plastic feet Shipping carton

Owners manual

Line cord

Output transformer Power transformer

FRONT PANEL AND TRIM

LAMPS

PANLOC SYSTEM

MISCELLANEOUS ITEMS

043-649

043-693

043-735 018-112

043-253

058-014 058-029

043-678 043-679

038-161 043-691

017-041 043-793

038-163 170-021

5C01106S-M9321JG

SCHEMATIC PART

NO.

038-321