DOWNLOAD Sony STR-DH550 / STR-DH750 Service Manual ↓ Size: 5.92 MB | Pages: 80 in PDF or view online for FREE

SAFETY  CHECK-OUT
After correcting the original service problem, perform the following
safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, 
screws, and all other exposed metal parts for AC leakage.
Check leakage as described below.

LEAKAGE  TEST
The AC leakage from any exposed metal part to earth ground and 
from all exposed metal parts to any exposed metal part having a 
return to chassis, must not exceed 0.5 mA (500 microamperes.). 
Leakage current can be measured by any one of three methods.
1.  A commercial leakage tester, such as the Simpson 229 or RCA 

WT-540A. Follow the manufacturers’ instructions to use these 
instruments.

2.  A battery-operated AC milliammeter. The Data Precision 245 

digital multimeter is suitable for this job.

3.  Measuring the voltage drop across a resistor by means of a 

VOM or battery-operated AC voltmeter. The “limit” indication 
is 0.75 V, so analog meters must have an accurate low-voltage 
scale. The Simpson 250 and Sanwa SH-63Trd are examples 
of a passive VOM that is suitable. Nearly all battery operated 
digital multimeters that have a 2 V AC range are suitable. (See 
Fig. A)

Ω

μF

Notes on chip component replacement
• 

Never reuse a disconnected chip component.

•  Notice that the minus side of a tantalum capacitor may be

damaged by heat.

0 OR  DOTTED  LINE  

0 ON  THE  SCHEMATIC  DIAGRAMS  AND  IN  

0 SUR  

 .............................................  

4

2-1. Case 

(Entry) 

....................................................................   5

2-2.  Front Panel Section .........................................................   6
2-3.  Back Panel Section .........................................................   7
2-4.  MAIN Board Section ......................................................   8
2-5. MAIN 

Board 

...................................................................   9

 ............................................................   10

 .............................................   13

5-1.  Block Diagram - ANALOG AUDIO Section - ...............   15
5-2.  Block Diagram - DIGITAL Section - .............................   16
5-3.  Block Diagram - AMP Section - .....................................   17
5-4.  Block Diagram - ANALOG VIDEO/USB Section - ......   18
5-5.  Block Diagram - DIGITAL VIDEO Section - ................   19
5-6.  Block Diagram - DISPLAY/POWER Section - ..............   20
5-7. Printed 

Wiring 

Board 

- MAIN Board (Component Side) - ................................   22

5-8. Printed 

Wiring 

Board 

- MAIN Board (Conductor Side) - ..................................   23

5-9.  Schematic Diagram - MAIN Board (1/7) - .....................   24
5-10.  Schematic Diagram - MAIN Board (2/7) - .....................   25
5-11.  Schematic Diagram - MAIN Board (3/7) - .....................   26
5-12.  Schematic Diagram - MAIN Board (4/7) - .....................   27
5-13.  Schematic Diagram - MAIN Board (5/7) - .....................   28
5-14.  Schematic Diagram - MAIN Board (6/7) - .....................   29
5-15.  Schematic Diagram - MAIN Board (7/7) - .....................   30
5-16. Printed Wiring Board 

- HDMI Board (Component Side) - ................................   31

5-17. Printed Wiring Board 

- HDMI Board (Conductor Side) - ..................................   32

5-18.  Schematic Diagram - HDMI Board - ..............................   33
5-19. Printed Wiring Board 

- STANDBY DCDC Board (Component Side) - ............   34

5-20. Printed Wiring Board 

- STANDBY DCDC Board (Conductor Side) - ..............   35

5-21.  Schematic Diagram - STANDBY DCDC Board - ..........   36
5-22.  Printed Wiring Board - PANEL Section - .......................   37
5-23.  Schematic Diagram - PANEL Section - ..........................   38
5-24.  Printed Wiring Board - FRONT JACK Board - ..............   39
5-25.  Schematic Diagram - FRONT JACK Board - ................   39
5-26.  Printed Wiring Board - TUNER1 Board - ......................   39
5-27.  Schematic Diagram - TUNER1 Board - .........................   40
5-28.  Printed Wiring Board - POWER KEY Board -...............   41
5-29.  Schematic Diagram - POWER KEY Board - .................   41
5-30.  Printed Wiring Board - HEADPHONE Board - .............   42
5-31.  Schematic Diagram - HEADPHONE Board - ................   42

6-1.  Case (Entry) Section .......................................................   57
6-2.  Front Panel Section .........................................................   58
6-3.  Back Panel Section .........................................................   59
6-4. Chassis 

Section 

...............................................................  60

 ..............................   61

DH550: US, Canadian

4-487-917-0[]

DH550: AEP, UK

4-487-917-1[]

DH550: Australian

4-487-917-2[]

DH550: 220 – 240 V AC area in E model

4-487-917-3[]

DH750: US, Canadian

4-448-923-0[]

DH750: AEP, UK

4-448-923-1[]

DH750: Australian

4-448-923-2[]

DH750: Taiwan

4-448-923-3[]

DH750: Mexican

4-448-923-4[]

DH750: Brazillian

4-448-923-6[]

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)

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!

• Strong 

viscosity

 

Unleaded solder is more viscous (sticky, less prone to fl ow) 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.

SPECIAL  COMPONENT  NOTICE
The components identified by mark 

9 contain confidential 

information.
Strictly follow the instructions whenever the components are 
repaired and/or replaced.

NOTICE  POUR  COMPOSANTS  SPÉCIAUX
Les composants identifiés par la marque 

9 contiennent des 

informations confidentielles.
Suivre scrupuleusement les instructions chaque fois qu’un compo-
sant est remplacé et / ou réparé.

NOTE  OF  REPLACING  THE  IC2402  AND  IC2900  ON  
THE  MAIN  BOARD
IC2402 and IC2900 on the MAIN board cannot exchange with 
single. When these parts on the MAIN board are damaged, 
exchange the entire mounted board.

NOTE  OF  REPLACING  THE  IC3514  ON  THE  HDMI  
BOARD
IC3514 on the HDMI board cannot exchange with single. When 
this part on the HDMI board is damaged, exchange the entire 
mounted board.

NOTE  OF  REPLACING  THE  IC902  (DH750)  ON  THE  
STANDBY  DCDC  BOARD
IC902 (DH750) on the STANDBY DCDC board cannot exchange 
with single. When this part on the STANDBY DCDC board is 
damaged, exchange the entire mounted board.

CAPACITOR  ELECTRICAL  DISCHARGE  PROCESSING
When checking the board, the electrical discharge is necessary for 
the electric shock prevention.
Connect the resistor to both ends of respective capacitors.

• Main 

Board

 C930, 

C931

:/2 W

Note:  This set can be disassemble according to the following sequence.

Note:  Follow the disassembly procedure in the numerical order given.

3 three screws
 (+BVTP 

u 8)

4

4

2 three screws
 (B-TYPE 

u 8)

5 case (entry)

1 three screws
 (B-TYPE 

u 8)

6 wire (flat type)
 

4 wire (flat type)
 

9 front panel section

8 five screws
 (+BVTP 

u 8)

3  Wire is removed
 

5  Wire is removed
 

1  Wire is removed
 

2 CN2900
 (5P)

7 CN391
 (4P)