McIntosh MI-3 Service manual

MI-3

MAXIMUM PERFORMANCE

INDICATOR

SERVICE INFORMATION

STARTING WITH SERIAL NO, 10E01

MclNTOSH LABORATORY INC. 2 CHAMBERS STREET BINGHAMTON, NEW YORK

MI-3

MI-3

SCHEMATIC NOTES

I. Unless otherwise specified: Resistance values are in ohms, 1/2 watt, and 10% tolerance;

capacitance values a re in microfarads (µF).

2 . Printed circuit board components are outlined on the schematics by dotted lines. The

circIed numbers around the dotted lines correspond to the numbers on the PC Board

layouts.

3. The terminal number ing of rotary switches is for reference only.

4. All voltages indicated on the schema tics 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 or antenna terminals.
d. AC

Input

at 117

e. Mode selector at test position.

5. In

6. In units with Serial No's from 10E26 to 15E00, R60 and R61 are used.

7. In units with Serial No's below 13E00, a 6W4 rectifier tube (Mclntosh Part No. 165-016)

8. In

units with

used in place of R59 •

is used in place of SR7 •

early units,

connected directly to pin No. 2 of S1 and the arm of R48B is connected directly to C7.

volts,

Serial

PC

Board

No's

50/60

below

043-984

Hz.

10E26,

two

neon

bulbs (Mclntosh Part

and R43 and R50 are not

used.

No.

058-002)

The arm of

R48A

are

is

AUDIO DRIVER

P.C. BOARD 043-984

VERTICAL AMPLIFIER

043-984

8

AUDIO DRIVER

NOTE

P.C. BOARD

HORIZONTAL AMPLIFIER

C.R.T. CIRCUIT

MI-3

Ml-3 154-434

MI-3

REPLACEMENT PARTS

All parts not listed are common items obtain­able from radio parts jobbers.

Replacement parts may be obtained when ordered
by PART NUMBER from:

Mclntosh Laboratory, Inc.
Customer Service Department
2 Chambers Street
Binghamton, New York 13903

(telephone [phone])

CAPACITORS

Symbol
Number

C3
C4

C5
C6

C7

C9, 10
C11

SR1,2

SR3,4
SR5,6

SR7

F1

Q1,2

T1

R1
R2
R3

R4
R5

R6

R29
R30
R32

MI-3

SCHEMATIC PART

Mylar .01 µF 400V

Elect. 20/20µF

Mylar -5µF 1000V
Elect. 8µF 475V
Mylar .22µF 200V
Mylar .22µF 250V
Mylar .1 µF 200V

Se. rectifier
Se. rectifier
Se. rectifier
Se. rectifier

Fuse 1 A slo-blo

Si . NPN transistor

NE2H Neon tube

Power transformer

Signal strength cal.
Deviation cal.

Left gain
Right gain
Vertical position

Horizontal position
Astigmatism

Intensity

Focus

Description

500/500V

DIODES

FUSES

TRANSISTORS

LAMPS

TRANSFORMERS

POTENTIOMETERS

NO.

038-462

Number
064-002

066-025

064-023
066-052

064-013
064-043
064-011

070-005
070-005
070-005
070-026

089-001

132-057

058-009

159-068

134-206
134-206

134-206
134-206
134-206
134-044
134-047
134-041
134-041

Part

R45
R48

R41
R42

S1
S2

V1 ,2

V3,4

V5
V6

V7,8

Vertical audio position

Audio gain

RESISTORS
Wirewound 15k 10% 10W
Wirewound 20k 10% 10W

SWITCHES

Selector switch

Power on-off

TUBES
6EA8
6EA8

3RP1 (CRT)

6EA8

OB2

FRONT PANEL & TRIM
Front panel
Front panel end cap: right

Front panel end cap: lef t
Power knob

Audio display knob

Intensity knob

Focus knob

Vertical position knob

Horizontal position knob

Scope test knob

MOUNTING SYSTEM
Shelf bracket: right
Shelf bracket: left
Mounting template #100
Hardware package

MISCELLANEOUS ITEMS

Fuseholder

AC power cord

Shipping carton
Owners manual

Audio cable

10C0819S7-M0462

134-206
134-171

139-040
139-018

146-100
146-040

165-044
165-044
165-028
165-044

165-027

043-697

018-132
018-133
043-253
043-253

043-478

043-478

043-478

043-478

043-806

043-427

043-428

038-179

043-458

178-001
170-021

043-943
038-142

170-015