XM-N502 - Sony Car Audio Service Manual (repair manual). Page 2

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.

CONFIRMING  THE  OPERATION (E and Indian models)
Please confi rm the car audio unit works even if REM output is not 
connected when you connect this unit with the car audio unit by 
the HIGH LEVEL input.

Thermal Protect
1.  Short across TH501 with the power on.
2.  Verify that the protector is operated and D918 illuminates 

green. When input the signal and verify that there is no output 
on the SP-OUT even when the volume is increased.

3.  Verify that the protector is released and there is an output on 

the SP-OUT when the short is removed.

4.  Likewise, perform items 1 to 3 for TH502, TH503 and TH504.

Over Current Protect
1.  Short between the positive and negative sides of the speaker 

output terminals CN903 with the power on.

2.  Verify that the protector is operated and D918 illuminates red.
3.  Verify that the protector is not released and D918 remains red 

even when the short is removed.

4.  Verify that the protector is released and D918 illuminates 

green when the power is turned off and then on again.

Offset Protect
1.  Short between the +12V terminal of CN903 and the BTL + or 

BTL – of the speaker output terminal CN903.

 

(Short between +12V terminal and BTL + and between +12V 
terminal and BTL –)

2.  Verify that the protector is operated and D918 illuminates red.
3.  Verify that the protector is not released and D918 remains red 

even when the short is removed.

4.  Verify that the protector is released and D918 illuminates 

green when the power is turned off and then on again.

NOTE  FOR  REPLACEMENT  OF  THE  TRANSISTORS
The transistors Q110, 111, 210 and 211 have two different ranks: 
P rank and Y rank.
The rank of these transistors need to be selected properly accord-
ing to each channel. When replacing any one of these transistors, 
check its rank and replace with the appropriate transistor of the 
same rank.

Rank

Q110, 210

Q111, 211

P

2SC5100-P

2SA1908-P

Y

2SC5100-Y

2SA1908-Y