HT-CT550W, SA-WCT550W - Sony Audio Service Manual (repair manual)

2011E05-1

© 

2011.05

•  SA-WCT550W is the active subwoofer 

in HT-CT550W.

• All of the units included in the HT-

CT550W (SA-WCT550W (main unit)/
SS-CT550W/STR-CT550WT/EZW-
RT50) are required to confi rming opera-
tion of the main unit. Check in advance 
that you have all of the units.

•  For the test modes for this unit, refer to the service manual of STR-CT550WT.

POWER OUTPUT (reference)

134 W (per channel at 
4 ohms, 100 Hz) 

Speaker system

Subwoofer, Bass reflex

Speaker unit

160 mm (6 3/8 in) cone 
type

Rated impedance

4 ohms

Power requirements

120 V AC, 60 Hz

Power consumption

On: 30 W
Standby mode: 0.5 W or less

Dimensions (approx.)

270 mm × 389 mm × 
280.5 mm (10 3/4 in × 
15 3/8 in × 11 1/8 in) 
(w/h/d)

Mass (approx.)

8.8 kg (19 lb 7 oz)

Design and specifications are subject to change without 
notice.

s Standby power consumption 0.5 W or less.
s Over 85 % power efficiency of amplifier block is 

achieved with the full digital amplifier, S-Master.

(US and Canadian models) 
220 - 240 V AC, 50/60 Hz 
(AEP and UK models)
120 V AC, 50/60 Hz
(Taiwan model)

This system incorporates Dolby* Digital and the 
DTS** Digital Surround System.

* Manufactured under license from Dolby 

Laboratories.
Dolby, and the double-D symbol are trademarks of 
Dolby Laboratories.

** Manufactured under license under U.S. Patent #’s: 

5,451,942; 5,956,674; 5,974,380; 5,978,762; 
6,226,616; 6,487,535; 7,212,872; 7,333,929; 
7,392,195; 7,272,567 & other U.S. and worldwide 
patents issued & pending. DTS, DTS-HD and the 
Symbol are registered trademarks, & DTS-HD 
Master Audio, and the DTS logos are trademarks of 
DTS, Inc. Product includes software. © DTS, Inc. 
All Rights Reserved.

This system incorporates High-Definition Multimedia 
Interface (HDMI

™

) technology.

HDMI, the HDMI Logo, and High-Definition 
Multimedia Interface are trademarks or registered 
trademarks of HDMI Licensing LLC in the United 
States and other countries.

“BRAVIA” logo is a trademark of Sony Corporation.

“x.v.Colour (x.v.Color)” and “x.v.Colour (x.v.Color)” 
logo are trademarks of Sony Corporation.

“PlayStation

®

” is a registered trademark of Sony 

Computer Entertainment Inc.

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.

SAFETY  CHECK-OUT
After correcting the original service problem, perform the follow-
ing 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)

0  OR  DOTTED  LINE  

0  ON  THE  SCHEMATIC  DIAGRAMS  AND  IN  

0  SUR  

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

2-1. Disassembly 

Flow 

...........................................................   4

2-2. AMP 

Block 

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

2-3.  Plate Top (AMP), Fuse (F900) ........................................   6
2-4.  SUB MAIN Board ..........................................................   6
2-5. POWER 

Board 

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

2-6.  Loudspeaker (16 cm) (SP100) ........................................   7

3-1. Block 

Diagram 

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

3-2. Printed 

Wiring 

Board 

 

- SUB MAIN Board (Component Side) - .......................   10

3-3. Printed 

Wiring 

Board 

 

- SUB MAIN Board (Conductor Side) - .........................   11

3-4.  Schematic Diagram - SUB MAIN Board - .....................   12
3-5. Printed 

Wiring 

Boards 

 

- LED CONNECT, FRONT LED Boards - ....................   13

3-6. Schematic 

Diagram 

 

- LED CONNECT, FRONT LED Boards - ....................   13

3-7.  Printed Wiring Board - POWER Board - ........................   14
3-8.  Schematic Diagram - POWER Board - ..........................   15

4-1. Speaker 

Section 

...............................................................  20

4-2. AMP 

Section 

...................................................................  21

  ..............................   22

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.

US and Canadian models

- 120V 60Hz 30W

AEP and UK models

- 220-240V 50/60Hz 30W

Taiwan model

- 120V 50/60Hz 30W

ADVANCE  PREPARATION  WHEN  CONFIRMING  OP-
ERATION
All of the units included in the HT-CT550W (SA-WCT550W (main 
unit)/SS-CT550W/STR-CT550WT/EZW-RT50) are required to 
confi rming operation of the main unit. Check in advance that you 
have all of the units.

NOTE  OF  REPLACING  THE  IC104  ON  THE  SUB  MAIN  
BOARD  AND  THE  COMPLETE  SUB  MAIN  BOARD 
When IC104 on the SUB MAIN board and the complete SUB 
MAIN board are replaced, it is necessary to spread the compound 
(THERMAL COMPOUND G747) (Part No. J-2501-221-A) be-
tween the sub main board and the heat sink.
Spread the compound referring to the fi gure below.

CAPACITOR  ELECTRICAL  DISCHARGE  PROCESSING 
When checking the board, for the electric shock prevention, con-
nect the resistors to both ends of respective capacitor (C935 or 
C936) to discharge the capacitor (C935 or C936).

:/2 W

LINK/STANDBY Indicator

You can check the status of wireless transmission between the 
receiver (STR-CT550WT) and the subwoofer (SA-WCT550W: 
main unit).
• Turns green:
  The system is turned on,wireless transmission is activated and 

sound signals are being received.

• Turns amber:
  The system is turned on,wireless transmission is activated with 

the Secure Link function, and sound signals are being received.

• Flashes in green quickly:
  The wireless transceiver is not inserted correctly into the wireless 

transceiver (EZW-RT50/EZW-RT20) slot.

• Flashes in green or amber slowly: 
  Wireless transmission is not activated.
• Turns red:
  The subwoofer is in standby mode
About the standby mode
The subwoofer enters standby mode automatically (the LINK/
STANDBY indicator turns red) when the receiver is in standby 
mode or wireless transmission is not activated. The subwoofer 
turns on automatically (the LINK/STANDBY indicator turns 
green) when the receiver is turned on and wireless transmission 
is activated.
• Turns off:
  The subwoofer is turned off.
• Flashes in red:
  The subwoofer’s protection is activated
If “PROTECTOR” and “PUSH POWER” appear alternate-
ly on the front panel display.
 Press 

?/1

 to turn off the system, and check the following item 

after “STANDBY” disappears.

• Is anything blocking the ventilation holes of the receiver?

If the receiver still does not operate properly after per-
forming the above measures, reset the receiver as fol-
lows:
Use buttons on the receiver for the operation.
1 Press 

?/1

?/1

 

“COLD RESET” appears and the receiver is reset. AMP menu, 
sound fi eld, etc., return to the default settings.

•  This set can be disassembled in the order shown below.