PN-G655RE (serv.man3). Complete - Sharp Monitor Service Manual (repair manual). Page 2

PN-G655RE   LEAD-FREE SOLDER

■ LEAD-FREE SOLDER

The PWB’ s of this model employs lead-free solder. The “LF” marks indicated on the PWB’s and the Service Manual mean “Lead-Free” solder. The
alphabet following the LF mark shows the kind of lead-free solder. 

When repairing a lead-free solder PWB, use lead-free solder thread. Never use conventional lead solder thread, which may cause a breakdown or an

accident. 

Since the melting point of lead-free solder thread is about 40°C higher than that of conventional lead solder thread, the use of the exclusive-use solder-

ing iron is recommendable. 

Since the melting point of lead-free solder is about 220°C, which is about 40°C higher than that of conventional lead solder, and its soldering capacity
is inferior to conventional one, it is apt to keep the soldering iron in contact with the PWB for longer time. This may cause land separation or may

exceed the heat-resistive temperature of components. Use enough care to separate the soldering iron from the PWB when completion of soldering is

confirmed. 

Since lead-free solder includes a greater quantity of tin, the iron tip may corrode easily. Turn ON/OFF the soldering iron power frequently.  

If different-kind solder remains on the soldering iron tip, it is melted together with lead-free solder. To avoid this, clean the soldering iron tip after com-
pletion of soldering work. 

If the soldering iron tip is discolored black during soldering work, clean

and file the tip with steel wool or a fine filer. 

5mm

Lead-Free

Solder composition 
code (Refer to the 
table at the right.)

Solder composition

Sn-Ag-Cu

Sn-Ag-Bi
Sn-Ag-Bi-Cu

Sn-Zn-Bi

Sn-In-Ag-Bi

Sn-Cu-Ni

Sn-Ag-Sb

Bi-Sn-Ag-P
Bi-Sn-Ag

a

b

z

i

n

s

p

Solder composition code

a