Precautions For Resoldering - Mitsubishi Electric SD420U Service Manual

PRECAUTIONS FOR RESOLDERING

Lead-free solder is handled in a different way from eutectic solder. See below for details.
How to distinguish circuit boards using lead-free solder from those using
eutectic solder
Circuit boards using lead-free solder
A mark of Pb Solder, Pb Joints, Pb PCA or LFS (for limited marking space) is printed near the board assembly number on
the component side.
Circuit boards using eutectic solder
Circuit boards using eutectic solder are divided into two groups.
- Boards having no mark of Pb Solder, Pb Joints, Pb PCA or LFS (for limited marking space) near the board assembly
number.
- Boards having a mark of Pb Solder, Pb Joints, Pb PCA or LFS (for limited marking space) that is painted out by a felt
pen near the board assembly number.
* Only when there is a limited marking space on the board, Pb Solder may be indicated as Pb S, Pb Joints as Pb J, and
Pb PCA as Pb P.
* Circuit boards using lead-free solder and those using eutectic solder may be used together in the same product.
Instructions for resoldering
- For circuit boards using lead-free solder, use lead-free solder.
- For circuit boards using eutectic solder, use eutectic solder.
- Separate the soldering iron for lead-free solder from that for eutectic solder completely for use.
(It is prohibited to use a same soldering iron for lead-free solder and eutectic solder.)
- For lead-free solder, it is advisable to use a soldering iron of at least 40 W because lead-free solder has a melting point
approx. 35˚C higher than that of eutectic solder as conventionally used. For wire solder, use M705ESC made by Senju
Metal Industry Co., Ltd.
- To remove solder, you can use desoldering wires for eutectic solder as conventionally used.
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