Mitsubishi Electronics WD-82737, WD-52527, WD-73837, WD-73737, WD-65737, WD-65C9, WD-60737 Pb Solder

MODELS: WD-60C9 / WD-65C9 / WD-73C9 / WD-60737 / WD-65737 / WD-73737 / WD-82737

WD-65837 / WD-73837 / WD-82837

Using Lead Free Solder

The symbol shown below indicates Lead (Pb) Free			• Poor wet-ability can cause solder balls.
solder was used during the construction of PWBs.			• Higher temperatures can cause flux spattering.
Only Lead Free solder should be used when servic-			• Soldering iron tip life is shortened.
ing these PWBs.			• Dull finish solder joints (not shiny) can appear to be
Solder must be compatible with that used by the			a “cold” solder joint.
manufacturer. Leaded solder can not be used on			In general a tip temperature of 700° F will usually provide
PWBs manufactured with Pb-free solder. The Mitsub-			good results.
ishi standard for service requires the use of Tin-Silver-
Copper (Sn-96.5, Ag-3.0, Cu-0.5). It can be obtained			Displays used to indicate Pb-free
through the Parts Department.
Order part number: PB FREE SOLDER			PCBs will be marked, indicating the level of Pb-free con-
			struction. Table 1 defines the levels by phase and shows
Lead Free solder has a higher melting point, and does			the different symbols that will be displayed on the PCB.
not “wet” as well as leaded solder. This means it does			Additionally, a PCB constructed using Pb-free solder may
not adhere as readily to the solder iron tip, and the			be simply marked LFS.
surface to be soldered. To counteract this, the flux			When possible, the indication will be placed close to the
used is more corrosive.
			part number that is screened onto the PCB (not the part
The following cautions must be taken when using Pb			label). Figure 1 is an example of a PCB showing the
Free solder.			display and its location.
• Higher temperatures can cause the PWB to
warp, detaching surface mount components.
• Higher temperatures may cause	Pb-Free					Short Display (When the
thermal damage to components.
	Phase		Definition		Display	area is too small)
• Higher temperatures can cause
	Phase-1	PCB's constructed using
plastics, such as connectors,		Pb-free solder.		Pb	Solder	Pb	S
relays, LEDs electrolytic
capacitors, etc. to melt or warp.	Phase-2	Solder, PCB surface
• Higher temperatures can cause
surface oxidation resulting in		finishing and component		Pb	Joints	Pb	J
		lead plating is Pb-free.
poor solder spread-ability and
		Components may have
wet-ability.		internal Pb.
• The flux is more corrosive.	Phase-3	Solder, PCB surface
• The time required for a good		finishing and components		Pb	PCA	Pb	P
solder connection may take		are Pb-free. (100% Pb-
longer.		free)

Table 1: Pb-Free Phases and Symbols

Pb-Free

Display

Pb Solder

Figure 1: Pb-Free display on PWB

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