HT-CT550W, SA-WCT550W - Sony Audio Service Manual (repair manual). Page 3

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.