File name p29.pdfRepair Tips 105E CM23 GSIII 29
9 Go to cover page
0. Warning 1.4 Attachment of SMDs
- Locate the SMD on the solder lands by means of tweezers and
All ICs and many other semi-conductors are susceptible to solder the component on one side. Ensure that the component is
electrostatic discharges (ESD). Careless handling during repair can positioned correctly on the solder lands (see Fig. 8.2A).
reduce life drastically. When repairing, make sure that you are - Next complete the soldering of the terminals of the component (see
connected with the same potential as the mass of the unit via a wrist Fiq. 8.2B).
wrap with resistance. Keep components and tools also at the same
potential ! MOUNTING
e.g. A PAIR OF TWEEZERS
1. Servicing of SMDs (Surface Mounted Devices)
A
1.1 General cautions on handling and storage
- Oxidation on the terminals of SMDs results in poor soldering. Do not
handle SMDs with bare hands.
- Avoid using storage places that are sensitive to oxidation such as SOLDER
places with sulphur or chlorine gas, direct sunlight, high 0.5 - 0.8 mm
PRESURE
temperatures or a high degree of humidity. The capacitance or SOLDERING
IRON
resistance value of the SMDs may be affected by this.
- Rough handling of circuit boards containing SMDs may cause
damage to the components as well as the circuit boards. Circuit
boards containing SMDs should never be bent or flexed. Different SOLDERING TIME SOLDER
< 3 sec/side 0.5 - 0.8 mm B
circuit board materials expand and contract at different rates when PRESURE
heated or cooled and the components and/or solder connections SOLDERING
IRON
may be damaged due to the stress. Never rub or sc |