LC-40LE631E (serv.man2) - Sharp TV Service Manual (repair manual). Page 5

Indicates lead-free solder of tin, silver and copper.

“ALL  PWB” of this model employs lead-free solder. The LF symbol indicates lead-free solder, and is attached on the 
PWBs and service manuals. The alphabetical character following LF shows the type of lead-free solder.
Example:

When fi xing the PWB soldered with the lead-free solder, apply lead-free wire solder. Repairing with conventional lead 
wire solder may cause damage or accident due to cracks.
As the melting point of lead-free solder (Sn-Ag-Cu) is higher than the lead wire solder by 40°C, we recommend you to 
use a dedicated soldering bit, if you are not familiar with how to obtain lead-free wire solder or soldering bit, contact our 
service station or service branch in your area.

As the melting point of lead-free solder (Sn-Ag-Cu) is about 220°C which is higher than the conventional lead solder by 
40°C, and as it has poor solder wettability, you may be apt to keep the soldering bit in contact with the PWB for extended 
period of time. However, Since the land may be peeled off or the maximum heat-resistance temperature of parts may be 
exceeded, remove the bit from the PWB as soon as you confi rm the steady soldering condition.
Lead-free solder contains more tin, and the end of the soldering bit may be easily corroded. Make sure to turn on and 
off the power of the bit as required.
If a different type of solder stays on the tip of the soldering bit, it is alloyed with lead-free solder. Clean the bit after every 
use of it.
When the tip of the soldering bit is blackened during use, fi le it with steel wool or fi ne sandpaper.

Be careful when replacing parts with polarity indication on the PWB silk.

Lead-free wire solder for servicing.

Indicates lead-free solder of tin, silver and nickel.

Sn-Ag-Ni