SERVICE MANUAL
Ref. No. 3677
SAFETY-RELATED COMPONENT
WARNING!!
COMPONENTS IDENTIFIED BY MARK
ON THE
SCHEMATIC DIAGRAM AND IN THE PARTS LIST ARE
CRITICAL FOR RISK OF FIRE AND ELECTRIC SHOCK.
REPLACE THESE COMPONENTS WITH ONKYO
PARTS WHOSE PART NUMBERS APPEAR AS SHOWN
IN THIS MANUAL.
MAKE LEAKAGE-CURRENT OR RESISTANCE
MEASUREMENTS TO DETERMINE THAT EXPOSED
PARTS ARE ACCEPTABLY INSULATED FROM THE
SUPPLY CIRCUIT BEFORE RETURNING THE
APPLIANCE TO THE CUSTOMER.
052001
A-905TX
INTEGRATED STEREO AMPLIFIER
A-905TX
UDT
120V AC, 60Hz
UPT
230-240V AC, 50Hz
STANDBY/ON
PHONES
STANDBY
A-905TX
INTEGRATED STEREO AMPLIFIER
TREBLE
BASS
BALANCE
POWER
OFF/1/2
--
+
--
+
L
R
PRESENCE
ACOUSTIC
CD
MD
TUNER
LINE/ DVD
TAPE
CDR/PC
SOURCE DIRECT
DIRECT
DIRECT
TONE
INPUT
ON
OFF
VOLUME
WIDE RANGE AMP TECHNOLOGY
CLOCK
SLEEP
EFFECT
GRAPHIC EQ
MODE
1
2
3
4
5
6
7
8
9
10/0
--/---
VOLUME
PRESET
FM
AM
PLAY MODE
PLAY MODE
REPEAT
CLEAR
SCROLL
MEMORY
REPEAT
CLEAR
DISC
REPEAT
CLEAR
ACOUSTIC
PRESENCE
TONE
RANDOM
TIMER
UP/DOWN
ENTER
MUTING
INPUT
TUNER
M D
DVD
C D
CDR
TAPE
REC
REC
PAUSE/STEP
STANDBY/ ON
REMOTE CONTROLLER
RC-
456S
A-905TX
SPECIFICATIONS
PART-XX
SERVICE PROCEDURES
PART-XX
Replacing the fuses
REF.NO.
PART NO.
DESCRIPTION
This symbol located near the fuse indicates that the
fuse used is show operating type, For continued protection against
fire hazard, replace with same type fuse , For fuse rating, refer to
the marking adjest to the symbol.
Ce symbole indique que le fusible utilise est e lent.
Pour une protection permanente, n'utiliser que des fusibles de meme
type. Ce demier est indique la qu le present symbol est apposre.
F901
252158
1.6A-UL/T-237, Fuse <DT>
252069
0.8A-SE-EAK, Fuse <PT>
F902-F904
2.5A-SE-EAK, Fuse <PT>
252075
NOTE:
<DT> : Asian model only for 120V
<PT> : Asian model only for 230V
A-905TX
CHASSIS EXPLODED VIEW
############
A51
A65
A66
A11
A10
A10
A11
A10
A61
A64
A63
A52
A58
A50
A67
U9
A1
A13
A55
A53
A54
A56
A73
A73
A16
U4
F901
A43
A43
A25
A26
E860
A34
A34
T901
Q523
Q525
Q526
Q524
Q528
Q527
A28
A10
P701
A10
A10
A10
U3
U2
P402
P402
A46
A49
A49
A49
A49
U7
U1
U8
U5
A41
A27
A27
P801
A81
A40
A11
A11
A11
P901
P584A
U10
F903
F904
F902
A47
A-905TX
CHASSIS EXPLODED VIEW PARTS LIST
############
REF NO.
PART NO.
DESCRIPTION
REF NO.
PART NO.
DESCRIPTION
A1
27111123
Front bracket
P402
27190011
KGLS-6S, Holder
A10
838130088
3TTB+8B, Self tapping screw
P584A
880009
Plastic rivet, NRP-345 <PT>
A11
838430088
3TTB+8B(BC), Self tapping screw
P701
27191106
UAMS-05S-2, Holder
A13
28198862
Facet, VOL
P801
25055436 or
NPLG-2P418, Shorted plug
A16
27100375D
Chassis
25055945
A25
27160451B
27160452B
A26
29110083
Adhesive tape, CROSS-16U
Q523,Q524
2202303 or
*
2SC4512-O or
A27
801525
3TTB+8B(BC), Special screw <PT>
2202304 or
*
2SC4512-Y or
838430088
3TTB+8B(BC), Self tapping screw <DT>
2202305
*
2SC4512-P, Transistor
A28
801433
3SMS8W.SW+14B(BC), special screw
Q525,Q526
2202313 or
*
2SA1726-O or
A34
27141530A
Retainer, HS-2
2202314 or
*
2SA1726-Y or
A40
27300750
Bussing cord
2202315
*
2SA1726-P, Transistor
A41
27122831
Rear panel <DT>
Q527,Q528
2212654 or
*
2SC3421-Y or
27122832
Rear panel <PT>
2212653
*
2SC3421-O, Transistor
A43
830440089
4TTC+8C(BC), Self tapping screw
A46
28184759-1
A47
29362571
Label, WARNING <DT,PT>
2301423
NPT-1374D, Power transformer <DT>
A49
838930088
Heat sink <DT>
P901
253277MIL
AS-UC-2#18, Power supply cord <DT>
Heat sink <PT>
253193HIT
AS-CEE, Power supply cord <PT>
Top cover
T901
3TTB+8B(UN), Self tapping screw
2301424
NPT-1374P, Power transformer <PT>
A50
838430107
3TTB+10S(BC), Self tapping screw
U1
1A905530-4B
NADG-6630-4B, Main circuit PC board ass'y <DT>
A51
27212298
Front panel
1A905530-4C
NADG-6630-4C, Main circuit PC board ass'y <PT>
A52
28198894
Facet 7P
U2
1A905531-4B
NAAF-6631-4B, Preamplifier circuit PC board ass'y <DT>
A53
28198895
Facet 1P
1A905531-4C
NAAF-6631-4C, Preamplifier circuit PC board ass'y <PT>
A54
28198925
Facet A
U3
1A905532-4B
NAAF-6632-4B, Acoustic circuit PC board ass'y <DT>
A55
27268037
Guide A
1A905532-4C
NAAF-6632-4C, Acoustic circuit PC board ass'y <PT>
A56
28325133
Knob, FM
U4
1A905533-4B
NAPS-6633-4B, Power supply circuit PC board ass'y <DT>
A58
28191798
Clear plate, RE
1A905533-4C
NAPS-6633-4C, Power supply circuit PC board ass'y <PT>
A61
28325926
Knob, INPUT
U5
1A905534-4B
NADIS-6634-4B, Display circuit PC board ass'y <DT>
A63
28135247Y
Badge
1A905534-4C
NADIS-6634-4C, Display circuit PC board ass'y <PT>
A64
28325925
Knob, VOL
U7
1A905536-4B
NAETC-6636-4B, Speaker terminal PC board ass'y <DT>
A65
28325674
Knob, TD
1A905536-4C
NAETC-6636-4C, Speaker terminal PC board ass'y <PT>
A66
28325927
Knob, TONE
U8
1A905537-4B
NAETC-6637-4B, Terminal PC board ass'y <DT>
A67
28325673
Knob, POWER
1A905537-4C
NAETC-6637-4C, Terminal PC board ass'y <PT>
A73
27175323
Leg AS
U9
1A905539-4B
NAETC-6639-4B, Power switch PC board ass'y <DT>
A81
29362630
Label, PROCESSOR
1A905539-4C
NAETC-6639-4C, Power switch PC board ass'y <PT>
F901
252158
1.6A-UL/T-237, Fuse <DT>
U10
1A905540-4C
NAETC-6640-4C, Fuse PC board ass'y <PT>
252069
0.8A-SE-EAK FSBFUSE, Fuse <PT>
F902-F904
2.5A-SE-EAK FUSE <PT>
NOTE:
<DT> : Asian model only for 120V
<PT> : Asian model only for 230V
NOTE: THE COMPONENTS IDENTIFIED BY MARK
ARE CRITICAL FOR RISK OF FIRE AND
ELECTRIC SHOCK. REPLACE ONLY WITH
PART NUMBER SPECIFIED.
CAUTON :
Replacement of the transistor of mark * ,if necessary,
must be made from the same beta group(HFE) as the
original type.
252075
SCHEMATIC DIAGRAM-1
U7
U9
U4
U10
U1
U8
SPEAKER TERMINAL PC BOARD
A-905TX
POWER SWITCH PC BOARD
POWER SUPPLY CIRCUIT
PC BOARD
FUSE PC
BOARD
MAIN CIRCUIT
PC BOARD
TERMINAL PC BOARD
-1.2
1.2
5.6
12.2
-12.2
12.4
11.8
-24.6
24.6
-1.2
1.2
-24.1
-24.6
24.6
24.1
-24.1
-24.6
24.6
24.1
E LENT. POUR UNE PROTECTION PERMANENTE,N'UTILISER
CE SYMBOLE INDIQUE QUE LE FUSIBLE UTLISE EST
INDIQUE LA QU LE PRESENT SYMBOL EST APPOSE.
QUE DES FUSIBLES DE MEME TYPE. CE DARNIER EST
RATING REFER TO THE MARKING ADJACENT TO THE SYMBOL
FOR CONTINUED PROTECTION AGAINST FIRE
HAZARD,REPLACE WITH SAME TYPE FUSE. FOR FUSE
THIS SYMBOL LOCATED NEAR THE FUSE INDICATES
THAT THE FUSE USED IS SLOW OPERATING TYPE
ATTENTION
V
A
ET CALIBRATION COMME INDIQUE.
D'INCENDIE, REMPLACER UNIQUEMENT
PERMANENTE CONTRE LES RISQUES
AFIN D'ASSURER UNE PROTECTION
PAR UN FUSIBLE DE MEME TYPE
V
A
AGAINST FIRE HAZARD, REPLACE
FOR CONTINUED PROTECTION
AND RATING INDICATED.
ONLY WITH FUSE OF SAME TYPE
CAUTION
P910
P307
D914-D917
GP104003E
+
JL702B
S951
S951
S951
P910
P910
*C312
221K
*C311
221K
*C308
101K
*C307
101K
*C304
101K
*C303
101K
*C302
101K
*C301
101K
*C320
101K
*C319
101K
*C316
101K
C315
101K
*C314
101K
*C313
101K
C712
104J
P951
P952
P902A
P911A
P912A
P951
P952
P951
P952
P911A
P912A
P951
P952
P902A
P951
P952
P912C
P911C
P911A
P912A
P914A
P913A
P951
P952
P902A
P911B
P902B
P912B
P586B
P585B
P586A
P585A
P501A
P401A
Q713
M51943B
G I
O
Q911
78M56
G I
O
R576
500B
R575
500B
R713 100K*7
R712
100K*4
JL901A
JL901A
JL901A
JL582B
P461B
JL901B
P405C
P502A
P403A
JL701B
Q704
DTA124ES
Q451
DTA114ES
Q702
TA7291S
1
2
3
4
5
6
7
8
9
X701
CST4.00MGW
D912
MTZJ12C
D913
MTZJ12C
D745
MTZJ5.1B
D705
MTZJ5.6B
D707
MTZJ5.1B
Q714
DTC144ES
Q912
DTC123JS
Q703
DTC144ES
RL901
RL901
D918
GP104003E
D706
D919
D702
D701
D704
D708
D722
D703
D911
RBV402
D3SBA30
P901
P901
P901
AC230-240V/50HZ
P901A
P901A
P901A
F901
1.6A/125V
F901
1.6A/125V
F902
T2AL250V
F904
T2.5AL250V
F903
T2.5AL250V
F901
Q701
HD404316-E30H
27
28
29
30
34
35
39
44
905/909
10
AVCC
15
AVSS
6
CE
43
CLK
40
DATA
42
DIRECT
14
GND
5
HP-IN
13
INPMUTE
26
KEYIN
9
LAT
41
MUTELED
20
NC
22
POFF
17
21
POWER2
25
PROTECT
36
REMIN
18
RESET
2
RIIN
12
RIOUT
11
SBASS1
31
SBASS2
32
SBASS3
33
SBASSLEDA
37
SBASSLEDB
38
SELIN1
7
SELIN2
8
SP-RELAY
19
TEST
1
VCC
16
VOLDOWN
24
VOLUP
23
X1
3
X2
4
L506
L502
L504
L501
L505
L503
JL581C
JL581A
P405B
P582
P584
R562
0.22*2
(2W)
R561
0.22*2
(2W)
C917
330/16
C916
330/16
C922
10/16
C919
47/16
C516
10/16
C515
10/16
C703
100/6.3
C701
0.1/5.5
C914
3300/35
C915
3300/35
C920
2200/16
C708
2.2/50
C322
10/16
C321
10/16
C451
2.2/50
C452
2.2/50
C711
1/50
Q533
2SA992
Q706
2SA933S-R
Q526
2SA1726
Q518
2SA992
Q520
2SA965
Q525 2SA1726
Q517
2SA992
Q519
2SA965
Q530
2SC1740S
Q528
2SC3421
Q527
2SC3421
Q529
2SC1740S
Q705
2SC1740S-R
Q532
2SC1845
Q522
2SC2235
Q524
2SC4512
Q516
2SC1845
Q531
2SC1845
Q523
2SC4512
Q521
2SC2235
Q515
2SC1845
P311A
P306
C951
0.01
C951
0.01
C309
101
C582
471
C581 471
C951
0.01
C921
223Z
C918
103J
C923
223Z
C913
104J
C912
104J
C517
473
C704
223Z
C707
223Z
C533
223Z
C702
474
C518
473
C532
223Z
C710
223Z
C709
223Z
C531
223Z
R916
0.47
(1/2W)
R916
0.47
(1/2W)
R554
2.2 (1/2W)
R552
2.2
(1/2W)
R551
2.2
(1/2W)
R353
1M
R916
0.47
(1/2W)
R543
100
(1/2W)
R550
15
(1/2W)
R582
10K
R581
680
R556
82
(1/2W)
R555
82
(1/2W)
R351
2.2K
R354
1M
R352
2.2K
R308
1M
R307
1M
R306
330
R305
330
R304
1M
R303
1M
R302
330
R301
330
R316
1M
R315
1M
R314
330
R313
330
R312
1M
R311
1M
R310
2.2K
R309
2.2K
R324
1M
R323
1M
R322
330
R321
330
R320
1M
R319
1M
R318
2.2K
R317
2.2K
R572
220
R568
1.8K
R570
1.2K
R574
220
R571
220
R567
1.8K
R569
1.2K
R573
220
R593
10
(1/2W)
R595
10
(1/2W)
R328
1M
R332
1M
R331
1M
R327
1M
R330
330
R326
330
R329
330
R325
330
R560
10
(1/2W)
R601
1K
R583
10K
R565
8.2
(1/2W)
R745
1K
R738
3.3K
R718
100K
R719
100K
R740
10K
R739
22K
R610
10K
R705
22K
R914
270
(1/2W)
R915
220
(1/2W)
R913
220
(1/2W)
R912
270
(1/2W)
R917
10
(1/2W)
R708
2.2K
R709
1K
R707
220K
R706
47K
R471
2.2K
R472
220K
R336
1M
R335
1M
R334
2.2K
R333
2.2K
R340
1M
R339
1M
R338
330
R337
330
R714
68K
R716
12K
R715
68K
R717
22K
R596
10
(1/2W)
R608
10K
R566 8.2
(1/2W)
R602
1K
R606
820
R604
680
R564
4.7
(1/2W)
R546
100
(1/2W)
R558
10
(1/2W)
R548
15
(1/2W)
R544
100
(1/2W)
R594 10 (1/2W)
R742
100K
R736
100K
R701 1M
R710
3.3K
R711
4.7K
R7351K
R7341K
R7331K
R605
820
R607
10K
R603
680
R563
4.7
(1/2W)
R553
2.2 (1/2W)
R559
10 (1/2W)
R549
15
(1/2W)
R545
100
(1/2W)
R547
15
(1/2W)
R557
10 (1/2W)
P305
P301
P302
P303
P304
Q301
TC9273N-010
10
11
12
17
18
19
20
21
22
23
24
25
26
27
CD
3
CDR-P
2
CK 15
DATA16
GND
13
L/DVD
5
MD-P
7
MD-R
6
ST
14
T-P
9
T-R
8
TU
4
VDD 28
VEE
1
UJJ
NAETC-6639
NAPS-6633
NPT-1374J
/60Hz
AC100V/50Hz
T901
UDT
NAETC-6639
AC120V/60Hz
NAPS-6633
NPT-1374D
T901
+B5
-B2
+B2
+B4
+B3
-B1
+B1
NAETC-6640
UPT
T800mAL250V
R
L
SPEAKERS
CDR/PC
NAETC-6636
D918
Acoustic Presence
AMP&VR
UPT
UJJ,UDT
NAETC-6639
ONE TIME ONLY
R742
R712,R713,R718,R719
USE
NO USE
PARTS
NUMBER
C301-C304,C307,C308
C311-C316,C319,C320
C581,C582
NPT-1374P
NAPS-6633
T901
TO
NADIS-6634
TO
NADIS-6634
TO
NADIS-6634
TO
NADIS-6634
TO NAAF-6631
TO NAAF-6631
TO NAAF-6632
TO NAAF-6632
TO NAAF-6631
NAETC-6637
NADG-6630
LINE/DVD
TUNER
MD
REC
REC
PLAY
PLAY
RIGHT
LEFT
RIGHT
LEFT
RIGHT
LEFT
CD
LEFT
LEFT
RIGHT
RIGHT
LEFT
RIGHT
RIGHT
LEFT
IN
OUT
PROCESSOR
*
+B1
+B1
MUTING
S.BASS1
S.BASS2
S.BASS3
POWER2
R
L
E
NF-R
NF-L
POWER2
E
E
L
L
R
R
E
E
E
R
R
L
L
+B2
-B2
*
*
-B1
+B1
HP-IN
DIRECT
KEYIN
MUTELED
+5.6V
E
REMIN
LED A
LED B
+5.6V
E
SELIN2
SELIN1
CLK
LAT
DATA
Lch
E
Rch
SUBWOOFER PREOUT
L-OUT
R-OUT
E
*
RI
P311B
P311B
TAPE
RIGHT
LEFT
RIGHT
LEFT
RIGHT
LEFT
RIGHT
LEFT
PLAY
REC
*
E
-B1
-B1
BY MARK
ARE CRITICAL FOR SAFETY
IDENTIFIED
NOTE
THE COMPONENTS
REPLACE ONLY WITH PART NUMBER SPECIFIED.
.
. VOLTAGE (MEASURED WITH VOLTMETER)
IS DC VOLTAGE. (NO INPUT SIGNAL)
. ALL PNP TRANSISTORS ARE EQUIVALENT
. ALL NPN TRANSISTORS ARE EQUIVALENT TO 2SC1815-GR UNLESS OTHERWISE NOTED.
. ALL DIODES ARE EQUIVALENT TO 1SS133 UNLESS OTHERWISE NOTED.
. ELECTROLYTIC CAPACITORS (
) ARE IN
F/WV.
. ALL CAPACITORS ARE IN pF/50WV UNLESS OTHERWISE NOTED.
EX) 030 3pF 330 33pF 331 330pF
u
ALL RESISTORS ARE IN OHMS 1/4WATTS UNLESS OTHERWISE NOTED.
. THE THICK LINES ON PC BOARD ARE THE PRINTING SIDE OF THE PARTS.
EX)
PRINTING SIDE
CIRCUIT IS SUBJECT TO CHANGE FOR IMPROVEMENT.
.
.
TO 2SA1015-GR UNLESS OTHERWISE NOTED.
333
0.033uF
A
1
2
3
4
5
BCD
E
F
G