Sharp LC-49CFE4041E, Service Manual

Page: 6 / 64

6
PRECAUTIONS FOR USING LEAD-FREE SOLDER
Employing lead-free solder
• “PWBs” 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:
Using lead-free wire solder
• When fixing the PWB soldered with the lead-free solder, apply lead-free wire solder. Re-
pairing 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.
Soldering
• 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 confirm the steady solder-
ing 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, file it with steel wool or fine sandpa-
per.
Indicates lead-free solder of tin, silver and copper.
L F a
Indicates lead-free solder of tin, silver and nickel.
L F n
Sn-Ag-Ni