Sony STR-DB900 User manual

STR-DB900
AEP Model
UK Model
E Model
SERVICE MANUAL
FM STEREO FM/AM RECEIVER
Sony Corporation
Audio Group
Published by Sony Engineering Corporation
9-879-123-01
2004H0278-1
© 2004.08
SPECIFICATIONS
Ver 1.0 2004.08
Manufactured under license from Dolby Laboratories.
“Dolby”, “Pro Logic” and the double-D symbol are
trademarks of Dolby Laboratories.
“DTS” and “DTS Digital Surround” are trademarks of Digital
Theater Systems, Inc.
Amplifier section
POWER OUTPUT
Rated power output in stereo mode
(8 ohms, 1 kHz, DIN) 120 W + 120 W
Reference power output
(8 ohms, 20 Hz – 20 kHz, THD 0.7%)
FRONT*: 100 W + 100 W
CENTER*: 100 W
SURROUND*:100 W + 100 W
SURROUND BACK*:100 W
* Depending on the sound field settings and source being used, there
may be no sound output.
Inputs (Analog) Sensitivity: 500 mV
Impedance: 50 kilohms
Inputs (Digital)
DVD (Coaxial) Impedance: 75 ohms
Outputs
LINE (subwoofer) Voltage: 2 V
Impedance: 1 kilohm
FM tuner section
Tuning range 87.5 – 108.0 MHz
Antenna terminals 75 ohms, unbalanced
Intermediate frequency 10.7 MHz
AM tuner section
Tuning range 531 – 1,602 kHz
Antenna Loop antenna
Intermediate frequency 450 kHz
General
Receiver
Power requirements 230 V AC, 50/60 Hz
Power consumption 130 W
Dimensions (w/h/d) 430 ×85 ×400 mm
including projecting parts and
controls
Mass (approx.) 6.2 kg
Remote control
Remote control system Infrared control
Power requirements 3 V DC with two R6 (size-AA)
batteries
Dimensions 210 ×49 ×25 mm
Mass (approx.) 85 g excluding batteries
Supplied accessories
FM wire antenna (1)
AM loop antenna (1)
Remote commander (1)
R6 (size AA) batteries (2)
Design and specifications are subject to change without notice.

STR-DB900
2
Unleaded solder
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
•Unleaded solder melts at a temperature about 40°C higher than
ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350°C.
Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0OR DOTTED LINE
WITH MARK 0ON THE SCHEMATIC DIAGRAMS AND IN THE
PARTS LIST ARE CRITICAL TO SAFE OPERATION. REPLACE
THESE COMPONENTSWITH SONY PARTSWHOSE PART NUM-
BERS APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLE-
MENTS PUBLISHED BY SONY.
•Strong viscosity
Unleaded solder is more viscous (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
•Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
Notes on chip component replacement
•Never reuse a disconnected chip component.
•Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
TABLE OF CONTENTS
1. SERVICING NOTES
1-1. AMP Board, DIGITAL Board Service Position .............. 3
1-2. Note on Checking AMP Board or DIGITAL Board
While Turning on Electricity ........................................... 3
1-3. Note on AMP Board Removal......................................... 4
1-4. Note on Heat Sink Installation ........................................ 4
1-5. Note on Checking POWER Board While Turning on
Electricity 1 ..................................................................... 5
1-6. Note on Checking POWER Board While Turning on
Electricity 2 ..................................................................... 5
2. GENERAL ................................................................... 6
3. TEST MODE ............................................................... 7
4. DIAGRAMS
4-1. Block Diagram — INPUT/TUNER Section — ............. 13
4-2. Block Diagram — AUDIO DSP Section —................... 14
4-3. Block Diagram — DAMP Section — ............................ 15
4-4. Block Diagram — DISPLAY Section — ....................... 16
4-5. Schematic Diagram — DIGITAL Section (1/3) —........ 17
4-6. Schematic Diagram — DIGITAL Section (2/3) —........ 18
4-7. Schematic Diagram — DIGITAL Section (3/3) —........ 19
4-8. Printed Wiring Board — DIGITAL Board (Side A) —.. 20
4-9. Printed Wiring Board — DIGITAL Board (Side B) —.. 21
4-10. Printed Wiring Board — AMP Board (Side A) — ......... 22
4-11. Printed Wiring Board — AMP Board (Side B) — ......... 23
4-12. Schematic Diagram — AMP Board (1/4) — ................. 24
4-13. Schematic Diagram — AMP Board (2/4) — ................. 25
4-14. Schematic Diagram — AMP Board (3/4) — ................. 26
4-14. Schematic Diagram — AMP Board (4/4) — ................. 27
4-15. Printed Wiring Board
— VIDEO, ANALOG IN Board — ................................ 28
4-16. Schematic Diagram
— VIDEO, ANALOG IN Board — ................................ 29
4-17. Printed Wiring Board — DISPLAY Section — ............. 30
4-18. Schematic Diagram — DISPLAY Section — ................ 31
4-19. Printed Wiring Board — POWER Section — ................ 32
4-20. Schematic Diagram — POWER Section — .................. 33
5. EXPLODEDVIEWS
5-1. Case Section .................................................................... 43
5-2. Front Panel Section ......................................................... 44
5-3. Chassis Section................................................................ 45
6. ELECTRICAL PARTS LIST .................................. 46

3
STR-DB900
SECTION 1
SERVICING NOTES
1-1. AMP BOARD, DIGITAL BOARD SERVICE POSITION
In case of checking AMP board or DIGITAL board from bottom side, please remove those with back panel.
1-2. NOTE ON CHECKING AMP BOARD OR DIGITAL BOARDWHILETURNING ON ELECTRICITY
In case of checkingAMP board or DIGITAL board while turning on electricity, please connect with an crocodile clip connector between back
panel and chassis.
AMP board
back panel DIGITAL board
insulating sheet
AMP board
DIGITAL board
chassis
back panel
crocodile clip connector

4
STR-DB900
1-3. NOTE ON AMP BOARD REMOVAL
1-4. NOTE ON HEAT SINK INSTALLATION
Be sure to install it in the direction as shown in the figure.
AMP board
In case of removing AMP board,
remove these 6 screws first, it is
easy to remove it.
heat sink
AMP board
insulating sheet

5
STR-DB900
1-5. NOTE ON CHECKING POWER BOARDWHILETURNING ON ELECTRICITY 1
In case of checking POWER board while turning on electricity, please connect with crocodile clip connectors between two ground terminals
(EP902, 904) and chassis.
1-6. NOTE ON CHECKING POWER BOARDWHILETURNING ON ELECTRICITY 2
Do not touch the capacitor (C916) on POWER board while turning on electricity, because of the voltage becomes 350VDC (Max.).
EP902
chassis
EP904
POWER board
crocodile clip connector
crocodile clip connector
C916
BOARDPOWER (SIDE B)

STR-DB900
6
SECTION 2
GENERAL This section is extracted
from instruction manual.
Main unit
DIRECT qa
DISPLAY 6
Display window 4
INPUT MODE 5
INPUT SELECTOR 7
MULTI CH IN qs
PHONES jack qg
POWER (power) switch 2
PRESET TUNING +/– qf
SOUND FIELD q;
STANDBY indicator 3
SURROUND BACK
DECODING qd
VOLUME 8
(remote sensor) 1
2CH 9
List of button locations and reference pages
ALPHABETICAL ORDER NUMBERS AND SYMBOLS
2 8
9
65371
qg qf qd qs qa q;
4

7
STR-DB900
SECTION 3
TEST MODE
[FLTEST MODE]
Fluorescent segments display test
Procedure:
1. Press the [POWER] button to turn the set off.
2. To enter the test mode, while pressing the two buttons [DISPLAY] and [SOUND FIELD], press [POWER] button.
3. All segments turn on.
4. To exit from this mode, press the [POWER] button to turn the set off.
[VERSION CHECK]
Firmware Version Check
Procedure:
1. Press the [POWER] button to turn the set off.
2. To enter the test mode, while pressing the two buttons [DIRECT] and [SOUND FIELD], press [POWER] button.
3. The message version “ DB9 CE 1.05 ” is displayed.
4. To exit from this mode, press the [POWER] button to turn the set off.
[KEY CHECK]
Check the buttons operate normally or not.
Procedure:
1. Press the [POWER] button to turn the set off.
2. To enter the test mode, while pressing the two buttons [DIRECT] and [SURR BACK DECODING], press [POWER] button.
3. The message “ RESET ** ” is displayed.
**: Number of buttons
4. Every time you press the button, ** counts down one by one.
5. In case of every buttons are pressed, the finished indication “ RESET 00 ” appears.
6. To exit from this mode, press the [POWER] button to turn the set off.
[SWAP ALL MODE]
Outputs of speakers checking mode. The L/R channel signals output from all of the speakers.
Procedure:
1. Press the [POWER] to turn the set off.
2. To enter the test mode, while pressing the two buttons [INPUT MODE] and [MULTI CH IN], press [POWER] button.
3. The message “ SWAPMODE ” is displayed.
4. The L/R channel signals output from all of the speakers.
5. In this mode, every time pressing [PRESET +] button, VOLUME LEVEL changes.
6. To exit from this mode, press the [POWER] button to turn the set off.
[HISTORY MODE]
Display of the internal information on the protector being activated.
(SF, Volume level value, Tone setting, Operating time)
Procedure:
1. Press the [POWER] button to turn the set off.
2. To enter the test mode, while pressing the two buttons [INPUT MODE] and [SURR BACK DECODING], press [POWER] button.
VOL MIN VOL 34 VOL MAX

8
STR-DB900
3. Select the display contents with cursor [ / ] buttons on the remote commander.
Note: In case of pressing buttons except for cursor [ / ] buttons, the Test Mode is released.
HISTORY
button
Display item number
* * * * * * * *
f
button
F
00
button
* * * * * * * *
f
button
F
10
button
* * * * * * * *
f
button
F
20
button
* * * * * * * *
f
button
F
30
button
* * * * * * * *
f
button
F
40
button
* * * * * * * *
f
button
F
01
button
VOL * *
f
button
F
11
Volume level (-40dB and below) operating time
Volume level (From -20dB to -39dB) operating time
Volume level (From -10dB to -19dB) operating time
Volume level (From 0dB to -9dB) operating time
Power ON total time
Operating time on the protector being activated
Volume level display value on the protector being activated
button
* * * * * * * *
f
button
F
21
button
* * * * * * * *
f
button
F
31
button
* * * * * * * *
f
button
F
41
button
f
button
F
Sound Field name display on the protector being activated
Input Selector name display on the protector being activated
Input Mode display on the protector being activated
* * * * * * * * 51
button
f
button
F
Input signal format type display on the protector being activated
* * * * * * * * 61
button
* * * * * * * *
f
button
F
71
button
* * * * * * * *
f
button
F
81
button
f
button
F
Configuration (Channel) display on the protector being activate
d
Speaker setting display on the protector being activated
Bass level display on the protector being activated
* * * * * * * * 91
Treble level display on the protector being activated
F f
F f
**---* : Each data display or numerical value.
Operating time display : Display in units of 5 minutes (Unit: Minutes)
(Ex.: 27 minutes - “25”, 10 minutes - “10”, 38 minutes - “35”, 20 hours - “1200”,
1 year - “525600”, 5 years - “2628000”

9
STR-DB900
(Display example on the protector being activated.)
•Item Number 01:
•Item Number 11:
•Item Number 21:
•Item Number 31:
•Item Number 41:
•Item Number 51:
•Item Number 61:
•Item Number 71:
•Item Number 81:
•Item Number 91:
•In case of the protector has never activated.:
4. To exit from this mode, press the [POWER] button to turn the set off.
Item Number
25 01
Operating Time
On 27 minutes operating time
25 11VOL
Volume level "25" display
PL 21DOLBY
Sound Field name display;DOLBY PRO LOGIC
31DVD
Input selector display;DVD
41AUTO IN
In using AUTO mode
41DIGITAL
NET MEDIA
41COAX IN
COAX FIX
41OPT IN
OPT FIX
41ANALOG
ANALOG FIX
51DOLBY D
DOLBY DIGITAL signal input
613/2 +LFE
[3/2.1] signal input
71HP IN
Headphones is inserted.
71SP ON
Headphones is not inserted
81BASS -06
Tone Bass Level is -6dB
91TREB -03
Tone Treble Level is -3dB
YZ________
All segments are "-"
Item Number

10
STR-DB900 SECTION 4
DIAGRAMS
•Circuit Boards Location
DISPLAY board
AC SW board
HP board
VOL board
VIDEO board
POWER board
AMP board
DIGITAL board
REG board
ANALOG IN board
tuner unit
LED board

11
STR-DB900
Note on Schematic Diagram:
•All capacitors are in µF unless otherwise noted. (p: pF)
50WV or less are not indicated except for electrolytics and
tantalums.
•All resistors are in Ωand 1/4W or less unless otherwise
specified.
• % : indicates tolerance.
• f: internal component.
•2: nonflammable resistor.
•C: panel designation.
•A: B+ Line.
•B: B– Line.
•Voltages and waveforms are dc with respect to ground un-
der no-signal conditions.
No mark : FM
*: Impossible to measure
•Voltages are taken with aVOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal production
tolerances.
•Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production
tolerances.
•Circled numbers refer to waveforms.
•Signal path.
F: FM
g: VIDEO
•Abbreviation
SP : Singapore model
MY : Malaysia model
NOTE FOR PRINTEDWIRING BOARDS AND SCHEMATIC DIAGRAMS
(In addition to this necessary note is printed in each block.)
Note on PrintedWiring Board:
•X: parts extracted from the component side.
•a: Through hole.
•: Pattern from the side which enables seeing.
•Abbreviation
SP : Singapore model
MY : Malaysia model
Caution:
Pattern face side: Parts on the parts face side seen from
(Side A) the parts face are indicated.
Parts face side: Parts on the pattern face side seen from
(Side B) the pattern face are indicated.
Note: The components identified by mark 0or dotted
line with mark 0are critical for safety.
Replace only with part number specified.

12
STR-DB900
•Waveforms
– DIGITAL Board –
80 nsec
1V AC/DIV, 50 nsec/DIV
3 Vp-p
1 IC217 qd CKOUT (O)
0.33 µ sec
1V AC/DIV, 0.2
µ sec/DIV
3.3 Vp-p
2 IC217 qf BCK (O)
21 µ sec
1V AC/DIV, 10
µ sec/DIV
3.3 Vp-p
3 IC217 qg LRCK (O)
80 nsec
1V AC/DIV, 50 nsec/DIV
3.1 Vp-p
4 IC217 w; XMCK (O)
80 nsec
1V AC/DIV, 50 nsec/DIV
3.3 Vp-p
5 IC217 wa XOUT (O)
74 nsec
1V AC/DIV, 50 nsec/DIV
3.3 Vp-p
6 IC206 qs MCLK2
80 nsec
1V AC/DIV, 50 nsec/DIV
3.3 Vp-p
7 IC206 qf SCKOUT
21 µ sec
1V AC/DIV, 10
µ sec/DIV
3.3 Vp-p
8 IC206 ql LRCKO
0.33 µ sec
1V AC/DIV, 0.1
µ sec/DIV
3.3 Vp-p
9 IC206 w; BCKO
80 nsec
1V AC/DIV, 50 nsec/DIV
3.5 Vp-p
0 IC202 <zvc X-OUT
– AMP Board –
20 nsec
2V AC/DIV, 20 nsec/DIV
5.2 Vp-p
1IC325 4
20 nsec
1V AC/DIV, 20 nsec/DIV
1.8 Vp-p
2IC301 wk XFSOIN
0.33 µ sec
1V AC/DIV, 0.1
µ sec/DIV
4 Vp-p
4CN315 wa BCKO
1V AC/DIV, 10 µ sec/DIV
5CN315 wd LRCKO
2V AC/DIV, 50 nsec/DIV
6CN315 wg CSCK
21 µ sec 3.3 Vp-p
80 nsec 4.7 Vp-p
20 nsec
1V AC/DIV, 20 nsec/DIV
3.3 Vp-p
3IC301 uj XFSOOUT
80 nsec
1V AC/DIV, 50 nsec/DIV
3.3 Vp-p
1 IC108 4
2.3 µ sec
1V AC/DIV, 1
µ sec/DIV
2.0 Vp-p
1 IC802 5OSC
– ANALOG IN Board – – DISPLAY Board –

1313
STR-DB900
STR-DB900
4-1. BLOCK DIAGRAM — INPUT/TUNER SECTION —
11
15
13 3 1
10
9
14
12
1
7
1
2
3
12
J701
J702
VIN1
VIN3
VOUT1
VOUT2
VIN2
VSEL-A VSEL-B
D807
NC
D806
10
5
2 13 114
1
3
7 3 16
14
2
10
11
12
13
6
5
4
3
9
1
IR RECEIVER
IC213
BUFFER
IC106
BUFFER
IC104
A/D CONVERTER
IC107
A/D CONVERTER
IC105
A/D CONVERTER
IC103
DIR
IC217
BUFFER
IC102
INPUT SELECT
IC101
IR TRANSMITTER
IC212
IR RECEIVER
IC218
IR RECEIVER
IC214
VIDEO INPUT SELECT
IC701
INPUT SELECT
IC211
3
1
1
5
12
11
10
15
7
12
13 1
11
10
15
7
12
1
11
10
15
7
22
20
21
14
15
13
34
10
35
36
37
38
47
48
24
J101
J201
R-CH
R-CH
X3
TU-TUNED
R-CH
8
10
6
7
11
3
2
1
4
13
15
14
TU-STEREO
TU-MUTE
TU-DATA
TU-DO
TU-CLK
TU-LATCH
RDS-SIG
RDS-DATA
RDS-INT
X
L CH
R CH
MUTE
STEREO
TUNED
CLK
FM SIG OUT
RDS-DATA
RDS-INT
CE
ST-DI/MC-DO
ST-DI/MC-DI
A
B
X2
X1
X0 ASEL-A
ADC-DATA-L/R
ADC-DATA-SL/SR
ADC-DATA-C/SW
DIR-DATA
BCK
LRCK
CONT-1
VINL DOUT
BCK
LRCK
SCKI
PDWN
DOUT
BCK
LRCK
SCJI
PDWN
+10V
ASEL-B
VINL
VINR
ADC-MCK
ADC-RST
+12V
1Y
A
B
2C0
2C1
2C2
2C3
1C0
1C1
1C2
1C3
DATA(O)
MCK
DIR-AUDIO
DIR-XMODE
DIR-CKSEL
DIR-CLK
DIR-CE
DIR-DI
DIR-DO
DIR-ERR
BCK(O)
CKOUT(I)
LRCK(O)
AUDIO-(O)
XMODE(I)
CKSEL1(I)
CL(I)
CE(I)
DI(I)
DO(O)
ERROR(O)
DIN0(I)
XMCK(O)
XIN(I)
XOUT(O)
X203
12.288MHz
DSEL-A
DSEL-B
2Y
Q202
IC108
41
Q201
R-CH
R-CH
J102
AEP,UK MODEL
Q102
Q101
L
FRONT
R
L
R
ANTENNA
AM
FM/AM TUNER
TM101
COAXIAL
FM
75Ω
MULTI
CH IN
SURROUND
CENTER
SUB WOOFER
L
R
L
R
ANALOG
DVD IN
DVD IN
OPTICAL
DIGITAL
VIDEO
VIDEO
IN
DVD IN
COAXIALIN
HDD/MD
IN
HDD/MD
OUT
VIDEO
IN
MONITOR
OUT
TV/SAT
IN
TV/SAT
IN
DVD
IN
CONT-2
3 1
+10V REG.
IC109
DELAY
Q203,204
LPF(0)
3 2
WAVE
SHAPER
IC216
VINL DOUT
BCK
LRCK
SCKI
PDWN
AAUDIO DSP
SECTION
(Page 14)
: FM
: VIDEO
• R-ch is omitted due to same as L-ch.
• Signal path

1414
STR-DB900
STR-DB900
4-2. BLOCK DIAGRAM — AUDIO DSP SECTION —
SEL
SDI2
DIR-DATA
ADC-DATA-L/R
ADC-DATA-SL/SR
ADC-DATA-C/SW
BCK
LRCK
6
Y5 30
+3.3V
SDO1
SDO3
SDO2
SDO4
BCKO
23
25
24
26
20
LRCKO 19
SCKOUT 14
HACN 32
HDIN 33
HCLK 34
HDOUT 35
HCS 36
GP12 37
GP9 68
PM 113
XRST 2
KFSIO 22
GP8
MCK
DIR-AUDIO
69
EXLOCK 59
DSP-HACN
5
DSP-DI
174
DSP-CLK
173
1
4
9
7
3
DSP-RST
DSP-PM
DSP-GP9
DSP-GP12
DSP-CS
DSP-DO
2
DIR-ERR
14
TUN-TUNED
155
TUN-STEREO
156
TUN-MUTE
157
TUN-DATA
153
TUN-DO
152
RDS-SIGNAL
53
RDS-DATA
158
RDS-INT
AEP,UK MODEL
102
TUN-CLK
151
TUN-LAT
154
ASEL-A
ASEL-B
DSEL-A
DSEL-B
VSEL-A
VSEL-B
ADC-RST
170
169
44
43
73
74
171
DIR-DI
11
DIR-CE
15
DIR-CLK
12
DIR-CKSEL1
22
XDIR-SEL
20
DIR-DO
TU-TUNED
DIR-ERR
TU-STEREO
TU-MUTE
TU-DATA
TU-DO
RDS-SIG
RDS-DATA
RDS-INT
TU-CLK
TU-LATCH
ASEL-A
ASEL-B
DSEL-A
DSEL-B
VSEL-A
VSEL-B
ADC-RST
DIR-DI
DIR-CE
DIR-CLK
DIR-CKSEL
DIR-XMODE
DIR-DO 21
DSP-BSTSEL
8
SDI2-SEL
19
DSP-BST
DATA-L/R
DATA-C/SW
DATA-SL/SR
DATA-SB
BCKO
LRCKO
SCK
EN
I-LIMIT
AMP
CONT
6XDAMP-RST 26
XDAMP-NSMUTE 27
XDAMP-EN 32
XDAMP-PROTECT 33
DAMP-DATA 24
DAMP-CLK 25
DAMP-CS1-L/R 28
DAMP-CS2-C/SW
DAMP-CS3-SL/SR
DAMP-CS4-SB
29
30
31
HP-SW 37
HP-RY-SO1 39
QS-RY/SW-RY-SO1
INIT
MUTE
SCDT
SHIFT
LATI-L/R
LATI-C/SW
LATI-SL/SR
LATI-SB
HP SW
PH-RY
RELAY
38
BST 56 Y
5A1
B2
SEL
6
SDI1
18
SDI3
114
BCKI1
17
LRCKI1
15
108,105-102,99, 98,80-77, 75-72
7-10,13-16, 29-32,35-38
5-1,44-42, 27-24,21-28
112,110,109, 97-92,82, 85-83,66-62
WEO
45
CSO
44
MCLK1
9
MCLK2
12
A
1
CONT-2
CONT-1
B
2
WE
D0
I
D15
D0
I
D
•
D08/GP0
I
D15/GP7
A0
I
A15
A0
I
A15
17
CS 6
XEPROM-DATA 76
XEPROM-CLK 75
SDA
5
SCL
6
X-IN 141
1
+3.3V
(STBY)
CN202
FLASH ROM
WRITE
X201
12.5MHz
EEPROM
IC209
AUDIO DSP
IC206
DATA SELECT
IC210
SDRAM
IC203
SYSTEM
CONTROL
IC202 (1/2)
BST SELECT
IC204
RESET
IC201
2
3
4
5
6
GND
STOP
+5V
3.3V
RESET
MD2
FLASH-SO
FLASH-SI
X-OUT 143
XRESET
+3.3V
144
MD2 138
FLASH-SO 126
FLASH-SI 125
1 2
+3.3V
REG.
IC205
3 1
RESET
Q301,302
X202
13.5MHz
BDAMP
SECTION
(Page 15)
DISPLAY
SECTION
(Page 16)
C
A
INPUT/
TUNER
SECTION
(Page 13)
: FM
• Signal path

1515
STR-DB900
STR-DB900
4-3. BLOCK DIAGRAM — DAMP SECTION —
DATA
1
7 5 7
5
2
3
OUTL1- 21
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
4
DIGITAL POWER AMP
IC307
OUTL2+ 15
OUTL2- 18
BCK
44
LRCK
45
INIT
XFSIIN
64
NSPMUTE
41
39
SCDT
38
SCSHIFT
37
SCLATCH
DATA
BCK
LRCK
INIT
XFSIIN
NSPMUTE
SCDT
SCSHIFT
SCLATCH
DATA
BCK
LRCK
INIT
XFSIIN
NSPMUTE
SCDT
SCSHIFT
SCLATCH
DATA
BCK
LRCK
INIT
XFSIIN
NSPMUTE
SCDT
SCSHIFT
SCLATCH
DATA-L/R
BCK
LRCK
INIT
DATA-L/R
DATA-C/SW
DATA-SL/SR
DATA-SB
BCKO
LRCKO
SCK
EN
AMP
CONT
P-STOP
I-LIMIT
BCK17
35
62
IC326
LRCK
SCK
SCK
MUTE
SCDT
SHIFT
LATI-L/R
DATA-C/SW
BCK
LRCK
INIT
SCK
MUTE
SCDT
SHIFT
LATI-C/SW
DATA-SL/SR
BCK
LRCK
INIT
SCK
MUTE
SCDT
SHIFT
LATI-SL/SR
DATA-SB
BCK
LRCK
INIT
SCK
MUTE
SCDT
SHIFT
LATI-SB
36
FSOI
FSOI
FSOI
FSOI
74
FSOCKO R-CH
73
43
44
45
64
44
45
64
41
39
38
37
36
41
39
38
37
36
44
45
64
43
41
39
38
37
36
43
I.PROTECT
Q356
RELAY DRIVER
Q305,306
V.PROTECT
Q317,318
TEMP.DETECT
Q346,347
DEAD TIME
IC303
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
OUTL1+ 10
77
OUTL1- 7
OUTL2+ 1
OUTL2- 4
4
BOOSTER
Q313,328
FRONT
R
TM302
TM305
R-CH
X300
49.125MHz
R-CH
R-CH
OUTL1+ DEAD TIME
IC309
BOOSTER
Q334,335
DIGITAL POWER AMP
IC319
24
28
LPF
15V-53V
TM303
LPF
D321
D315
THP303
OUTL1- 21
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
4
DIGITAL POWER AMP
IC328
WOOFER AMP
IC311
OUTL2+ 15
OUTL2- 18
74
I.PROTECT
Q360
V.PROTECT
Q321,322
TEMP.DETECT
Q350,351
DEAD TIME
IC310
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
77
OUTL2+ 10
OUTL2- 1
51
4
BOOSTER
Q336,337
OUTL1+ DEAD TIME
IC314
PCM/PWM
PROCESSOR
IC308
PCM/PWM
PROCESSOR
IC313
PCM/PWM
PROCESSOR
IC605
BOOSTER
Q338,339
DIGITAL POWER AMP
IC329
24
28
LPF
15V-53V
TM304
LPF
D323
D317
THP304
OUTL1- 21
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
4
DIGITAL POWER AMP
IC330
OUTL2+ 15
OUTL2- 18
74 R-CH
I.PROTECT
Q362
V.PROTECT
Q323,324
TEMP.DETECT
Q352,353
DEAD TIME
IC315
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
OUTL1+ 10
77
OUTL1- 7
OUTL2+ 1
OUTL2- 4
4
BOOSTER
Q340,341
D601
THP601 TEMP.DETECT
Q608,610
OUTL1+
XFSOIN
DEAD TIME
IC601
BOOSTER
Q601,602
DIGITAL POWER AMP
IC603
24
28
LPF
15V-53V
SURROUND
BACK
+12V
(GATE)
AVDD
(+5V)
DVDD
(+3.3V)
TM601
LPF
Q329
Q316 Q315 Q314
Q327
Q609
D602
OUTL1- 21
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
4
DIGITAL POWER AMP
IC604
OUTL2+ 15
OUTL2- 18
74
I.PROTECT
Q612
V.PROTECT
Q602,606
DEAD TIME
IC602
5 HIN
LIN
HOUT
HSCT
LOUT
6
3
8
4
1
6
4
BOOSTER
Q603,604
SURROUND
R
SURROUND
L
RELAY RELAY DRIVER
Q307,308
PROTECT
CONTROL
IC327
3 1
+5V
REG.
IC322
DELAY
BUFFER
IC324(1/2), Q310
DELAY
BUFFER
IC324(2/2), Q311 3 1
+3.3V
REG.
IC323
J301
RY302
AUDIO OUT
J401
RY301 PHONES
CENTER
SUB WOOFER
6
B
AUDIO DSP
SECTION
(Page 14)
D
DISPLAY
SECTION
(Page 16)
SPEAKERS
IMPEDANCE USE
4-16Ω
43 OUTL1+
XFSOIN
XFSOOUT
XFSOIN
XFSOOUT
XFSOIN
XFSOOUT
DEAD TIME
IC302
LPF
IC320
CLOCK OSC
IC325
PCM/PWM
PROCESSOR
IC301
HEADPHONE AMP
IC321
BOOSTER
Q304,309
DIGITAL POWER AMP
IC306
24
28
1 3
6
LPF
15V-53V
FRONT
L
TM301
LPF
D316
PH-RY
HPSW
D322
THP301
2
4
+12V(DAMP)
+12V(DAMP)
: FM
• R-ch is omitted due to same as L-ch.
• Signal path

1616
STR-DB900
STR-DB900
4-4. BLOCK DIAGRAM — DISPLAY SECTION —
7
123
10013
VOUT
KEY NETWORK
S802-806
S807-810
122 121
45
638
21
BUFFER
IC803
FL DRIVER
IC802
SYSTEM
CONTROL
IC202 (2/2)
T801
+6.5V
D803
VEE
V-CONT
P-CONT1
AC-STOP
+3.3V
+12V
-12V
(DAMP)
+10V
(GATE)
+12V
(DAMP)
+6.5V
+6.2V
+3.3V
(STBY)
15V-53V
SIRCS
KEY1
LED-STANDBY
VOL-UP
VOL-DOWN
INPUT-UP
INPUT-DOWN
KEY2-QS-ONLY
+5V
910
SEG1
I
SEG16
GR1D1
I
GR1D12
FL801
FLUORESCENT
INDICATOR
TUBE
DIN
FL-DATA
FL-CLK
FL-LATCH
8
CLK
9
STB
3 1
47
86
98
P-STOP
GATE
Q920,D931
GATE
Q905,908
Q907
Q902
RECT
D930
RECT
D905
D920
D930
D921
D933 D919
(+5.6V)
116
120
RV801
VOLUME
(ENCODER) 119
51
50
D808
STANDBY
118
RV802
INPUT SELECT
(ENCODER) 117
STOP
30
+3.3V
14
I
29
42
I
31
3 1
1
4 3
5
2
3 2
3 1
1
3
2
+17V REG.
Q901
RECT.
D913
RECT.
D914
RECT.
D915
+10V REG.
IC907
-12V REG.
IC906
+3.3V REG.
IC904
+3.3V REG.
IC910
BUFFER
IC909
SHUNT
REG.
IC905
+3.3V REG.
IC908
SHUNT REG.
IC903
SWITCHING
REGULATOR
IC902
IR RECEIVER.
IC801
SWITCHING
REGULATOR
IC901
FB
AMP
DRAIN
VCC
T902
Q903
DCB/FB
SURCE
GND
3
4
5
DRAIN
D912 D906
D902 D904
D929 D903
T901
VC
FL902
FL901
F901
S1
~
AC IN
POWER
ON/OFF
VCC
1OCP/SYNC
2GND
PB/OLP
+15V REG.
Q912,914
+5V REG.
Q910
+20V REG.
Q904
FEED BACK
ISOLATOR
PC901
AC-STOP
ISOLATOR
PC902
BUFFER
Q906,917
RIPPLE
FILTER
Q990
D801,802
D804,805
RECT.
3 1
8
1
1
3
2 1
4 3
DC/DC
CONVERTER
Q801,802
LED
DRIVER
Q803
REF
IN+ OUT
D932
(5.6V)
D
C
DAMP
SECTION
(Page 15)
AUDIO DSP
SECTION
(Page 14)

1717
STR-DB900
STR-DB900
4-5. SCHEMATIC DIAGRAM — DIGITAL SECTION (1/3) —
IC216
IC211
R379 R390 X203
C291
C292
R381
C293 C294
FB210
R380
R385
R384
R383
R382
R387 FB209
FB212
C295 R378
D202
R386
C286
C285
C288
C289
C290
R372
R369
C282
C284
R374
R371
R349
R348
C266
C281
R368
R362 R364
R361
R353
R352
C264
R351
R350
R370
C279
R366
R355
C273
D201
R358
FB208
R359
R356
R367
C269
C270
R373
C283
C280
R363
J201
IC218
IC214
IC213
IC212
C262
R345
R346
C263
R354
C271
R344
C260
C261
R340
R343
FB207
EP202
L201
Q203
Q204
Q201
Q202
C278
C276
IC217
CN207
TC7WU04F
SN74HC153
1M 330 12.288M
39p
22p
3.3k
0.1 220
10V
0UH
100
100
100
22
22
100 0UH
0
470p 1k
1SS355
1M
0.01
0.1
0.1
10
220
10V
6.8k
47k
2200000p
3.3
50V
100
47k
100
10k
0.01
0.1
3.3k
100 100
4.7k
10k
10k
10
100
100
5.6k
0.1
10k
100k
220
10V
1SS355
0
0UH
470k
47k
470
47
25V
0.1
75
0.1
22
25V
100
1P
TORX141L
TORX141L
TORX141L
TOTX141L
(RED)
0.1
100
100
0.1
100
0.1
0
0.1
10
50V
10k
10k
0UH
DTC114EKA-T146
DELAY
DTC114EKA-T146
DELAY
DTC114EKA-T146
INVERTER
DTC114EKA-T146
INVERTER
47
25V
0.1
LC89056W
25P
BUS
+3.3V
GND
202-43
202-44
207-1
207-2
207-3
207-4
207-5
207-6
207-7
207-8
207-9
207-10
207-11
207-12
207-13
207-15
207-17
207-19
207-21
207-23
207-224
207-225
AUDIO
XSTATE
DATA
LRCK
BCK
CK OUT
202-12
XMCK
202-11
202-21
202-13
202-20
202-22
202-10
202-14
IR TRANSMITTER
IR RECEIVER
IR RECEIVER
IR RECEIVER
INPUT SELECT
WAVE SHAPER
DIR
BOARD
(Page 25)
OPTICAL
DIGITAL
DIGITAL
COAXIAL
AMP
(2/3) (3/3)
DIGITAL DIGITAL
BOARD
BOARD
(Page 18) (Page 19)
• See page 12 forWaveforms. • See page 34 for IC Block Diagrams.

1818
STR-DB900
STR-DB900
4-6. SCHEMATIC DIAGRAM — DIGITAL SECTION (2/3) —
IC210
R331
C250
C249
C256
C254
R322 C258 C259
X202
R323
R329
R337 FB206
R339
FB211
R332
R333
R334
R335
R336
R234
R233
R225
R224
R223
R222
R221
R220
R219
R232
R231
R230
R229
R228
R227
R226
R268
R267
R266
R262
R263
R264
R265
R261
R260
R259
R258
R255
R254
R253
R252
C210
IC203
C212
C214
CN203
IC205
C240 C247
FB203
C248
C241
C228
C234
R298
C233
IC206
R314
R313
R311
R308
R306
R296
R295
C230
C232
C223
R284
C221
IC204
C220
C219
FB202
C222
R289
R277
R278
FB204
C246
C237
C245
R235
TC7WH157FK
100
0.1
0.1
0.1
0.01
10k 22p 22p
13.5MHz
1M
1k
100 0UH
22
0UH
220
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
0.1
IC61LV6416-15TG
100
16V
0.1
23P
NJM2391-26
0.1 1
0UH
0.1
470
10V
0.1
0.1
10k
10
CXD9718Q
100
100
100
100
100
100
100
0.1
0.1
10
10k
0.1
TC7WH157FK
0.1
100
16V
0UH
0.1
100
100
100
0UH
0.1
10
0.1
100
BUS
10V
+3.3V
GND
5V
203-2
203-3
203-4
203-5
203-6
203-7
203-8
203-9
203-10
203-11
203-12
203-13
203-1
207-13
207-15
207-17
207-19
207-21
207-23
207-225
CK OUT
BCK
LRCK
202-3
202-2
XMCK
202-92
202-93
202-94
202-95
202-96
202-97
202-98
202-99
202-96
202-97
202-98
202-99
202-102
202-103
202-104
202-105
202-107
202-108
202-109
202-110
202-112
202-102
202-103
202-104
202-105
202-107
202-108
202-109
202-110
202-112
206-64
206-65
206-66
206-64
206-65
206-66
206-72
206-73
206-74
206-75
206-77
206-78
206-79
206-80
206-82
206-83
206-84
206-85
206-45
206-44
202-8
202-6
202-13
AUDIO
202-7
202-5
DSP DI
DSP CLK
202-1
202-4
202-9
206-45
206-44
202-19
DATA
202-95
202-94
202-93
206-72
206-73
206-74
206-75
206-77
206-78
206-79
206-80
202-92
206-82
206-85
206-84
206-83
AEP,UK DATA SELECT
AUDIO DSP
SDRAM
BAT SELECT
+3.3V REG
BOARD
ANALOG IN
BOARD
(3/3)
DIGITAL DIGITAL
BOARD
(1/3)
(3/3)
DIGITAL
BOARD
(Page 19)
(Page 17) (Page 19)
(Page 29)
• See page 12 forWaveforms. • See page 34 for IC Block Diagrams. • See page 37 for IC Pin Function Description.

1919
STR-DB900
STR-DB900
4-7. SCHEMATIC DIAGRAM — DIGITAL SECTION (3/3) —
JR203
JR201
JR204
R316
C274
C302
R394
D303
C203
R393
R392
D302
D301
C301
R391
C201
IC201
CN202
EP201
C297
FB201
CN201
CN206
C268
CN209
R330
R338
R389
R388
C251
R318
R326
R328
R327
R320 R321
C236
C242
R324 R325
R312
R307
R303
C229
C226
C225
R285
R287
R288 R291
R237
R251 R248 R245 R242
R236
R239
R241
R244
R247
R250
R257
C211
C213
C215
C216
C218
C205
C208
C204
R208
R217
R210
X201
C209
R206
R212
R213
R207
R214
R215
R216
R203
R202
C207
R204
R205
R209
R211
C206
R218
C217
C227
R290
R269
R270
R271
R272
R274
R275
R276
R279
R280
R282
R283
R286
R294
C224
R304
R309
R299
R302
C231
R293
R375
C238
R315 C239 C235
IC202
Q301
Q302
R317
C253
C252
IC209
C267
FB205
R256
R249
R246
R243
R240
R238
0
0
0
10k
10
50V
10k
1SS352-TPH3
0.1
10k
68k
1SS352-TPH3
1SS352-TPH3
0.1
100
0.01
S-80929CMMC-G8Z
6P
0.1
0UH
17P
#SAN11P
47
25V
5P
10k
10k
100
100
0.1
10k
1k
1k
1k
10k 10k
0.1
220
10V
1k 1k
100k
10k
10k
0.1
0.1
0.01
10k
1k
100 100
1k
10k 10k 10k 10k
1k
1k
1k
10k
10k
10k
10k
0.01
0.01
0.01
0.01
0.1
0.1
0.1
0.1
10k
0
3.3k
12.5MHz
0.1
1k
100
100
1k
1k
1k
1k
47k
47k
0.1
1k
1k
10k
10
0.1
10k
0.1
0.1
10k
1k
1k
1k
1k
100
100
100
100
100
100
100
100
1k
0.1
1k
1k
10k
10k
0.1
10k
1k
0.1
0.022 0.1
MB91354APMT
-G-104-BNDE1
DTC114EKA-T146
RESET
2SC2712
RESET
1k
0.022
0.022
BR24L16F-WE2
47
25V
0
1k
1k
1k
1k
1k
1k
BUS
10V
+3.3V
GND
5V
12
2
3
4
5
6
7
8
9
10
11
1
12
2
3
4
5
6
7
8
9
10
11
1
203-2
203-3
203-4
203-5
203-6
203-7
203-10
203-11
203-12
203-13
203-1
207-1
207-4
207-2
207-5
207-6
207-7
207-8
207-9
207-10
207-11
207-12
207-224
207-3
202-44
202-43
DSP CLK
DSP DI
203-8
203-9
202-11
202-10
202-12
202-13
202-14
XSTATE
202-19
202-20
202-21
202-22
202-1
202-2
202-3
202-4
202-5
202-6
202-7
202-8
202-9
*1
*2
SP,MY
SP,MY
SP,MY
SP,MY
*2 R315
2.2k
0
SP,MY
AEP,UK
SP,MY
AEP,UK
*1 C274
100/16V
100/50V
SYSTEM CONTROL
EEPROM
RESET
BOARD
BOARD
BOARD
VIDEO
POWER
DISPLAY
(FOR CHECK)
(2/3)
DIGITAL
BOARD
BOARD
(2/3)
DIGITAL DIGITAL
BOARD
(1/3)
(Page 31)
(Page 33)
(Page 17) (Page 18)
(Page 18)
(Page 29)
• See page 12 forWaveforms. • See page 34 for IC Block Diagrams. • See page 39 for IC Pin Function Description.

2020
STR-DB900
STR-DB900
4-8. PRINTEDWIRING BOARD — DIGITAL BOARD (SIDE A) — •See page 10 for Circuit Boards Location. :Uses unleaded solder.
• Semiconductor
Location
Ref. No. Location
D202 A-6
D303 D-1
IC201 D-1
IC202 C-2
IC203 C-6
IC204 D-5
IC205 D-4
IC206 C-5
IC209 B-3
IC210 D-4
IC211 C-7
IC216 C-7
IC217 B-7
Q201 D-7
Q202 D-7
Q301 D-2
Q302 C-1
1 4
85
13
1
24
48
12
3625
37
1
44
88
132
89
45
133 176
122 44 23
130
9061
31 60
120
91
916 81
E
E
14
8
5
1
13
4
85
58 4
1
1
13
54
52
E
E
6
JR203
C289
R272
R309
R271
IC217
FB212
C211
R381
R318
R241
R270
R236
R325
R324
C291
IC201
C292
X203
R291
R379
R239
C224
C231
R390
R282
FB209
R304
R299
R302
R326 R327
R328
R216 R215
C215
R214
R213
R212
C213
R207
R206
R205
R204
R256
R249
R246
R243
R240
R359
R238
R211
FB204
R356
R344
Q201
Q202
C216
IC216
R339
FB211
R331
R332
R294
R337
R329
C246
R314
R313
R311
C301
R308 R306
R284
C222
C240 C247
R298
R264
R263
R262
R261
R260
R259
R258
R254 R253
R252
R222
R221
R220
R219
R232
R231
R230
R229
R233
R234
R223
R224
R225
R277
R278
R268
R267 R266
R255
IC211
IC205
R265
R323
X202
R368
R364
R362
D202
R383
R387
FB206
R382
R384
R385
R371
C282
C286
C285
R374
R358
R367
IC203
IC204
IC210
CN202 X201
IC209
IC202 IC206
R343
R340
R348
R349 C266
R350
R351
Q302
Q301
R393
D303
(FOR CHECK)
(SIDE A)DIGITAL BOARD
11
(11)
1-862-295-
23 4 5 6 7 8
A
1
B
C
D
E