HT-DDW990, STR-K990 - Sony Audio Service Manual (repair manual). Page 3

3

• Never reuse a disconnected chip component.

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

damaged by heat.

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 viscou-s (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.

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

4

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

............................. 13

................................................................. 14

4-1.

Block Diagram – MAIN Section – .................................. 15

4-2.

Block Diagram – DISPLAY/POWER Section – ............. 16

4-3.

Printed Wiring Board  – DIGITAL Board (Side A) – ...... 17

4-4.

Printed Wiring Board  – DIGITAL Board (Side B) – ...... 18

4-5.

Schematic Diagram  – DIGITAL Board (1/5) – .............. 19

4-6.

Schematic Diagram  – DIGITAL Board (2/5) – .............. 20

4-7.

Schematic Diagram  – DIGITAL Board (3/5) – .............. 21

4-8.

Schematic Diagram  – DIGITAL Board (4/5) – .............. 22

4-9.

Schematic Diagram  – DIGITAL Board (5/5) – .............. 23

4-10. Printed Wiring Board  – MAIN Board – ......................... 24
4-11. Schematic Diagram  – MAIN Board (1/4) – ................... 25
4-12. Schematic Diagram  – MAIN Board (2/4) – ................... 26
4-13. Schematic Diagram  – MAIN Board (3/4) – ................... 27
4-14. Schematic Diagram  – MAIN Board (4/4) – ................... 28
4-15. Printed Wiring Boards

– DISPLAY Board, POWER KEY Board – .................... 29

4-16. Schematic Diagram

– DISPLAY Board, POWER KEY Board – .................... 30

4-17. Printed Wiring Boards

– STANDBY Board, DCDC Board – .............................. 31

4-18. Schematic Diagram

– STANDBY Board, DCDC Board – .............................. 32

4-19. Printed Wiring Boards

– DCAC Board, VIDEO3 Board – .................................. 33

4-20. Schematic Diagram

– DCAC Board, VIDEO3 Board – .................................. 34

4-21. Printed Wiring Boards

– VIDEO Board, HEADPHONE Board – ....................... 35

4-22. Schematic Diagram

– VIDEO Board, HEADPHONE Board – ....................... 36

4-23. Printed Wiring Board  – HDMI SW Board – .................. 37
4-24. Schematic Diagram  – HDMI SW Board – ..................... 38

5-1.

Front Panel Section ......................................................... 47

5-2.

Chassis Section ................................................................ 48

.................................. 49

Th

Moreover, it is possible to distinguish the model
by Part No..

e area code of the receiver you purchased is 

shown on the lower right portion of the rear panel 
(see the illustration below).

Any differences in operation, according to the area 
code, are clearly indicated in the text, for example, 
“Models of area code AA only”.

ONT A

SURROUND

CENTER

Area code

Part No.

Model

Part No.

US Model

2-897-800-7

Canadian Model

2-897-800-8