Suggested Pb-Free Solder; Servicing Of Surface-Mounted Devices (Smds) - HP LT3200 Service Manual

•
Special information for Pb-free BGA-ICs: These ICs
will be delivered in so-called dry-packaging to protect
the IC against moisture and with the Pb-free logo on it.
This packaging may only be opened shortly before it is
used (soldered). Otherwise the body of the IC gets wet
inside, and during the heating time the structure of the
IC will be destroyed from steam pressure. If the
packaging was opened before usage the IC has to be
heated up for about 90 hours to dry. Make sure you use
ESD protection!

Suggested Pb-Free Solder

Several kinds of Pb-free solder (some shown in the
following illustration) are available for purchase. This
product uses Sn+Ag+Cu (tin (SN), silver (AG), copper
(CU)) solder. However, Sn+Cu (tin (SN), copper (Cu)),
Sn+Zn+Bi (tin (SN), zinc (Zn), bismuth (Bi)) solder can
also be used.
Servicing of Surface-Mounted Devices
(SMDs)
CAUTIONS:
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 places with sulphur or chlorine gas,
direct sunlight, high temperatures, or a high degree of
humidity. The capacitance or resistance value of the
SMDs may be affected by these conditions.
•
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 circuit board materials expand
and contract at different rates when heated or cooled and
the components and/or solder connections may be
damaged due to the stress.
•
Never rub or scrape chip components as this may cause
the value of the component to change. Similarly, do not
slide the circuit board across any surface.
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HP High-Definition LCD TV Service Manual
Removal of SMDs
1 Heat the solder (for 2 to 3 seconds) at each terminal of
the chip. By means of soldier wick and a slight
horizontal force, small components can be removed with
the soldering iron. They can also be removed with a
solder sucker (A).
2 While holding the SMD with a pair of tweezers, take it
off gently using the soldering iron's heat applied to each
terminal (B).
3 Remove the excess solder on the solder lands by means
of soldier wick or a solder sucker (C).
CAUTIONS:
•
When handling the soldering iron, use suitable pressure
and be careful.
•
When removing the chip, do not use undue force with
the pair of tweezers.
•
The soldering iron to be used (approx. 30 W) should
preferably be equipped with a thermal control (soldering
temperature: 360º to 380º C).
•
Once removed, the chip cannot be reused.