STR-DH720, STR-DH720HP - Sony Audio Service Manual (repair manual). Page 3

 ...................................................... 3

2-1. Case 

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

2-2. D-VIDEO 

Board 

................................................................. 6

2-3.  Front Panel Section ............................................................. 6
2-4.  Back Panel Section ............................................................. 7
2-5. DIGITAL 

Board 

.................................................................. 7

2-6.  MAIN Board Section .......................................................... 8
2-7. MAIN 

Board 

....................................................................... 8

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

 ....................................11

5-1.  Block Diagram – TUNER/AUDIO Section – ................... 13
5-2.  Block Diagram – DIGITAL Section – .............................. 14
5-3.  Block Diagram – STANDBY-A VIDEO PC Section–...... 15
5-4.  Block Diagram – D-VIDEO Section – ............................. 16
5-5.  Block Diagram – KEY/DISPLAY/USB Section – ........... 17
5-6.  Block Diagram – POWER KEY Section – ....................... 18
5-7.  Printed Wiring Board – DIGITAL Board (Side A) – ........ 20
5-8.  Printed Wiring Board – DIGITAL Board (Side B) – ........ 21
5-9.  Schematic Diagram – DIGITAL Board (1/4) –................. 22
5-10.  Schematic Diagram – DIGITAL Board (2/4) –................. 23
5-11.  Schematic Diagram – DIGITAL Board (3/4) –................. 24
5-12.  Schematic Diagram – DIGITAL Board (4/4) –................. 25
5-13.  Printed Wiring Board – MAIN Board – ............................ 26
5-14.  Schematic Diagram – MAIN Board (1/4) – ...................... 27
5-15.  Schematic Diagram – MAIN Board (2/4) – ...................... 28
5-16.  Schematic Diagram – MAIN Board (3/4) – ...................... 29
5-17.  Schematic Diagram – MAIN Board (4/4) – ...................... 30
5-18.  Printed Wiring Board – D-VIDEO Board (Side A) – ....... 31
5-19.  Printed Wiring Board – D-VIDEO Board (Side B) – ....... 32
5-20.  Schematic Diagram – D-VIDEO Board (1/4) – ................ 33
5-21.  Schematic Diagram – D-VIDEO Board (2/4) – ................ 34
5-22.  Schematic Diagram – D-VIDEO Board (3/4) – ................ 35
5-23.  Schematic Diagram – D-VIDEO Board (4/4) – ................ 36
5-24.  Printed Wiring Board –
 

STANDBY-A VIDEO PC Board – ................................... 37

5-25.  Schematic Diagram –
 

STANDBY-A VIDEO PC Board – ................................... 38

5-26.  Printed Wiring Boards – PANEL Section – ...................... 39
5-27.  Schematic Diagram – PANEL Section – .......................... 40
5-28.  Printed Wiring Board – DCDC Board – ........................... 41
5-29.  Schematic Diagram – DCDC Board – .............................. 42
5-30.  Printed Wiring Board – USB Board – .............................. 43
5-31.  Schematic Diagram– USB Board – .................................. 44
5-32.  Printed Wiring Board – HEADPHONE Board – .............. 45
5-33.  Schematic Diagram – HEADPHONE Board – ................. 45
5-34.  Printed Wiring Board – TEMP-SENSOR Board – ........... 45
5-35.  Schematic Diagram – TEMP-SENSOR Board – .............. 45

6-1. Case 

Section 

...................................................................... 65

6-2. DCDC 

Board 

..................................................................... 66

6-3.  Front Panel Section ........................................................... 67
6-4.  Back Panel Section ........................................................... 68
6-5. Chassis 

Section 

................................................................. 69

 ..................................... 70

STR-DH720: US

4-261-825-3[]

STR-DH720: Canadian

4-261-825-4[]

STR-DH720: AEP

4-261-825-5[]

STR-DH720HP: US

4-261-825-7[]

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.

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)

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 confi dentielles.
Suivre scrupuleusement les instructions chaque fois qu’un com-
posant est remplacé et / ou réparé.

Note: Refer to supplement-1 for the printed wiring board, 

schematic diagram and electrical parts list of D-VIDEO 
board (Suffix-21), DIGITAL board (Suffix-21), DCDC 
board (Suffi x-21), MAIN board (Suffi x-24) and STANDBY-
AVIDEO MT PC Board (Suffi x-24).