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