UP-800 (serv.man23). UP-820N, UP-820F Service Manual - Sharp ECR Service Manual (repair manual). Page 2

UP-820N/820F (V)   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 soldering iron is rec-
ommendable. 

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 tem-
perature 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. 

■ SPECIAL CAUTIONS 

Target model : UP-820N/UP-820F
Special cautions for production and servicing are described below.

•  Since transparency is the vital factor of the transparent touch panel, use a great care not to put fingerprints or dirt on the transparent touch panel.

Use clean finger sucks, gloves, and a mask, and never touch the visible area. 

•  Do not apply a pressure to the pressure-inhibit area of the touch panel when assembling and handling. 

•  Since the glass edges are not chamfered and there are some sharp edges, always use finger sucks or gloves when handling. 

•  Never hold the flexible pattern section of the transparent touch panel in order to maintain the reliability.

•  Never put a touch panel over another in order to prevent them from scratching. 

•  Never put a heavy material, a hard material, or a sharp material on the transparent touch panel. 

• To remove dirt from the surface of the transparent touch panel, use soft cloth immersed in ethyl alcohol. If, however, ethyl alcohol soaks into the

attachment section of the film and the glass, separation or malfunction may occur. Use enough care for it. 

•  If there is a scratch or dirt on the platen roller or the platen drive wheel, defective printing may occur. If an external pressure is applied to the plate

section, it may be deformed easily. Use enough care when assembling and handling. 

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