Akai AM-2600 User manual

AKAI STEREO INTEGRATED AMPLIFIER
move. AM-2600
SECTION 1 SERVICEMANUAL ..............-00e0000- 1
SECTION 2 PARTS LIST ......... 00 cccccecececeecees 15
SECTION 3 SCHEMATIC DIAGRAM. ...................24

SECTION 1
SERVICE MANUAL
TABLE OF CONTENTS
I. TECHNICAL DATA: g: cs:i Sdn se gehik etd hacen Se eee wae Sard ene die MAE eee LA oe
Il. DISMANTLING OF UNIT 20... cc cc eee reer e eee e nee e ene e nena
Ill. CONTROUS oes 5.8 5G 8 BARE RIS MAAS BD iE are Thales Gd etaes dee EARLY HS
IV PRINCIPAL PARTS LOCATION... 1... occ e een ees
V. LEVEL, DIAGRAM) -)) ei h04 oe tare De cree ew eee eee ee a eee bide dag Co dele ey Rae
VI. MAIN AMPLIFIER ADJUSTMENT... 1. cc en ene n eee e nee eaee
1. IDLING CURRENT ADJUSTMENT oo. eee een eens oe
2. LEVEL METER ADJUSTMENT... eee nnn nee eens
Vil. CLASSIFICATION OF VARIOUS P.C BOARDS ..... 0... e ees
1. RELATION OF P.C BOARD TITLE AND IDENTIFICATION NUMBER .................
2. COMPOSITION OF VARIOUS P.C BOARDS ..... 1... oes
For basic adjustments, measuring methods, and operating principles, refer to GENERAL OPERATING
PRINCIPLES AND ADJUSTMENTS.

|. TECHNICAL DATA
POWER AMPLIFIER SECTION
CONTINUOUS POWER OUTPUT —
2-CHANNELS DRIVEN
with no more than 0.1% total harmonic distortion.
POWER BANDWIDTH (IHF) 7 Hz to 40 kHz/8 ohms (Total Harmonic Distortion: 0.1%) a
SIGNAL TO NOISE RATIO (IHF) a 7 _
PHONO Better than 75 dB
___AUX | _ Better than 95 dB = :
RESIDUAL NOISE __ te | Less than 0.5 mV at 8 ohms -
CHANNEL SEPARATION (IHF)
ee ___ _ PHONO Better than 55 dBat1,000Hz
DAMPING FACTOR _ > More than 60(1kHz,8 ohms)
OUTPUT SPEAKERS A, B (4 to 16 ohms)/A+B ( 8 to 16 ohms)
HEADPHONE 4 to 16 ohms
POWER INDICATOR METERS (2) 3/80W switchable ;
PREAMPLIFIER SECTION
INPUT SENSITIVITY /IMPEDANCE
PHONO
AUX
TUNER
Phono 2: 3 mV/33, 47 or 100 k ohms
Phono 1: 3 mV/50 k ohms
150 mV/100 k ohms
150 mV/100 k ohms
TAPE MONITOR PIN: 150 mV/100 k ohms
; 7 ce DIN: 150 mV/100 k ohms.
OUTPUT LEVEL/IMPEDANCE
TAPE REC | PIN: 150 mV/100 k ohms
DIN: 30 mV/180 k ohms _
FREQUENCY RESPONSE
PHONO (RIAA EQUALIZATION)
TUNER, AUX, TAPE MONITOR
30 Hz to 15 kHz +0.8 dB, —0.8 dB
7 Hz to 70 kHz +0 dB, -1 dB _
TONE CONTROL | BASS +9 dB at 100 Hz
: TREBLE | +9 dBat 10 kHz = :
LOUDNESS CONTROL +10 dB at 100 Hz, +6 dB at 10 kHz (High Position)
+10 dB at 100 Hz (Low Position)
7 (Volume Control set at —30 dB position)
FILTER HIGH —5 dBat 7 kHz (7 kHz position)
—3 dB at 10 kHz (10 kHz position) |
LOW —2 dB at 50 Hz (30 Hz position)
eee —6 dB at 50 Hz (60 Hz position) oe
MISCELLANEOUS
SEMICONDUCTORS Transistors: 35 Diodes: 17
POWER REQUIREMENTS
DIMENSIONS _
CSA, UL and LA models: 120V, 60 Hz
CEE models: 220V, 50 Hz
Other models: 110/220/240V, 50/60 Hz switchable
440(W) x 141(H) x 331(D)mm, (17.3 x 5.6 x 13 inches)
WEIGHT
10 kg (22 lbs)
* For improvement purposes, specifications and design are subject to change without notice.

lt. DISMANTLING OF UNIT
In case of trouble, etc. necessitating disassembly, please disassemble in the order shown in photographs. Reassemble in
reverse order.
I
5
SCREWS
[ 2
CABINET
SCREWS
BOTTOM PLATE
FRONT PANEL SCREWS
SCREWS
CONTROL KNOBS

il. CONTROLS
NRO =
oOnN OO FW
. SPEAKER SYSTEM SELECTOR
. OUTPUT POWER LEVEL METERS
(Left and Right)
. METER SWITCH
. MODE SWITCH
. LOUDNESS SWITCH
. VOLUME CONTROL
. STEREO BALANCE CONTROL
. INPUT SELECTOR
. POWER SWITCH
10.
11.
2s.
13.
14.
15.
16.
17.
18.
HEADPHONE JACK
AUDIO MUTE SWITCH
LOW FILTER SWITCH
HIGH FILTER SWITCH
TONE SWITCH
BASS TONE CONTROL
TREBLE TONE CONTROL
POWER INDICATOR LAMP
TAPE MONITOR SWITCH
Fig. 1 Controls

IV. PRINCIPAL PARTS LOCATION
LEFT ch
HEAT SINK
@
POWER SWITCH
Swg0l
FUSE TERMINAL
POWER TRANSFORMER
CAPACITOR C902 ,903
iIOOOOpF 63V
ara TAPE RC BOARD M2-5435
SPEAKER SYSTEM
sw90
£Q AMP PC BOARD
M2- 5617A
_[e|_-
TONE CONTROL PC BOARD M2-5618
8
Li if it
©
POWER LEVEL METER
LEFT M901
SELECTOR
2
POWER LEVEL METER
RIGHT M902
HEADPHONE JACK
J90I
'__ AUDIO MUTE SWITCH SW4
MAIN AMP RC BOARD
M2- 5432A
RIGHT ch
HEAT SINK
BASS TONE TREBLE TONE
CONTROL VRI
TONE SWITCH SWI
“—-HIGH FILTER SWITCH SW3
=n ————e oa
q } ®
-— PC BOARD M2-5619
Fig. 2 Top View
METER SWITCH SW3
-—MODE SWITCH SWI
-—LOUDNESS SWITCH SW2
BALANCE CONTROL
VRIA
VOLUME CONTROL | INPUT SELECTOR
VRIB swt
LED RC BOARD
TAPE MONITOR SWITCH
M2-5617C sw
CONTROL VR2
POWER INDICATOR
DI
“— LOW FILTER SWITCH Sw2
Fig. 3 Front View
5

V. LEVEL DIAGRAM
LEVEL IN dB
Sa
30
20
~20
-40
-50
AUX
TAPE MONITOR (PIN)
TAPE MONITOR
(DIN)
PHONO
SPEAKER
CONTROL AMP MAIN AMP HEADPHONES
|
_—
TAPE REC(PIN)
TAPE REC(DIN)
SPEAKER OUTPUT
(29dB)
TAPE MONITOR(DIN)!
AUX, TUNER TAPE MONITOR(PIN): 150mA
(-14dB)
(EQ AMP)
|
|
|
a
|
I
|
|
|
|
|
|
|
|
{
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|
|
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|
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|
|
|
|
|
|
|
|
|
22V/8 OHMS
i
|
|
|
!
|
NN
|
av
(MAIN
AMP)
HEADPHONES
(4¢4B)
0.77V/
8
OHMS
:
(0dB)
(CONTROL
AMP)
TAPE
REC
(PIN)
1SOmv (-14dB)
TAPE REC(DIN)
30mv (-28dB)
PHONO 3mvV
FREQUENCY [kHz 4
(-48dB)
Fig. 4 Level Diagram of Model AM-2600

VI. MAIN AMPLIFIER ADJUSTMENT
1. IDLING CURRENT ADJUSTMENT
TESTER
IDLING CURRENT ADJ
(L CHANNEL )
VR |
elie a ~
Connect a tester to Power Amp. P.C Board test point
between Pin-11 and Pin-12, and between Pin-29 and
Pin-28.
Adjust semi-fixed resistors VR-la, VR-1b until the volt-
age is 30 mV.
2. LEVEL METER ADJUSTMENT
SPEAKER
OUTPUT
AC VOLTMETER
Aubio osc °
IKHz
Fig. 6 Level Meter Adjustment
a) Connect instruments as shown in Fig. 6.
b) Turn volume control knob on the front panel until
the AC voltmeter indicates 4.9 volts (3 watts).
c) Adjust VR-3a,b so that level-meter indicates 3 watts.
(Refer to Fig. 7)
TESTER
Ae
IDLING CURRENT ADJ ("
(R CHANNEL) (4)
ui TREb
a TR3b
TRIb tT
28 0
TR4b | |
<<) TR7b 270
026
oO 23 24 25
Fig. 5 Main Amp. P.C Board M2-5432A
Fig. 7 Volume P.C Board M2-5619

Vil.
CLASSIFICATION
OF
VARIOUS
P.C
BOARDS
i
1.
RELATION
OF
P.C
BOARD
TITLE
AND
IDENTIFICATION
NUMBER
7
PC
Board
Title
- ;
7
7
;
PC
Board
Number
a
"Main
Amplifier
PCBoard
_—
M25432
;
2
Tone
Control
P.C
Board
Po
M2-5618
=
Equalizer
P.C
Board
;
M2-5617
~
Volume
P.C
Board
_
Loe
M2-5619
Tape
P.C
Board
M2-5435_
Chart-1

2. COMPOSITION OF VARIOUS P.C BOARDS
1) MAIN AMPLIFIER P.C BOARD M2—5432 2ED
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