Akai AM 2650 Service Manual

Page 2

SECHONI

SERVICE MANUAL

TABLE OF CONTENTS

I. TECHNICAL DATA ...................................................... 2
1. MODEL AT-2650 ................................................... 2
2 MODEL AM»265O .................................................. 3
II. DISMANTLING OF UNIT ................................................... 4
1, MODEL AT72650 ................................................... 4
2. MODEL AM-2650 S
III CONTROLS ..................... 6
1. MODEL AT-2650 ..................................................... 6
2, MODEL AM-2650 .................................................... 7
IV, PRINCIPAL PARTS LOCATION .............................................. 8
11 MODEL AT-26SO ..................................................... 8
2. MODEL AM-2650 .................................................... 9
V. OPERATING PRINCIPLES OF QUADRATURE DETECTION SYSTEM .................... 10

VI. OPERATING PRINCIPLES OF PLL CIRCUIT EMPLOYED IN
STEREO DEMODULATION CIRCUIT ........................................ 12

1. PLL CIRCUIT OPERATION ............................................. 1

I, STEREO DEMODULATION CIRCUIT ............................ 13
VII, OPERATING PRINCIPLES OF FM NOISE CANCELLER CIRCUIT ....................... 15
1. BASIC CIRCUIT FOR PULSE NOISE SUPPRESSION .............................. 15
2. OPERATION PRINCIPLE WITH STEREO SIGNALS ............................... 15
3. ADJUSTMENT METHOD FOR THE PILOT SIGNAL GENERATING CIRCUIT ............. 16
VIII LEVEL DIAGRAM .......................................... I . 17
IX. TUNER ADJUSTMENT (AT-2650) ............................................. 18
I, FM TUNER SECTION ADJUSTMENT ........................................ 19
21 AM TUNER SECTION ADJUSTMENT ....................................... 20
X. AMPLIFIER ADJUSTMENT (AM-2650) ......................................... 21
1. IDLING CURRENT ADJUSTMENT .......................................... 21
2. LEVEL METER INDICATION ADJUSTMENT ................................... 22
XII TUNING CORD THREADING ................................................ 23
XII. CLASSIFICATION OF VARIOUS P.C BOARDS .................................. 24
1, PC BOARD TITLE AND IDENTIFICATION NUMBER ............................. 25
21 MODEL AT-2650 COMPOSITION OF VARIOUS P,C BOARDS ....................... 28
3, MODEL AM<2650 COMPOSITION OF VARIOUS PIC BOARDS ........................ 52

SC HEMATIC DIAGRAM

For basic adjustments, measuring methods, and operating principles, Iefer to GENERAL TECHNICAL
MANUAL