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Ch i p Component I nformation
Replacing Chip Components
Chip components are installed at the fac
tory by a series of robots. The first one places a
spot of adhesive resin at the location where
each part is to be installed, and later robots
handle and place parts using vacuum suction.
For single-sided boards, solder paste is ap
plied and the board is then baked to harden
the resin and flow the solder. For double-sided
boards, no solder paste is applied, but the
board is baked (or exposed to ultra-violet) to
cure the resin before dip soldering.
In our laboratories and service shops, small
quantities of chip components are mounted
manually by applying a spot of resin, placing
with tweezers, and then soldering by very
small dual streams of hot air (without physical
contact during soldering). We remove parts by
first removing solder using a vacuum suction
iron, which applies a light, steady vacuum at
the iron tip, and then breaking the adhesive
with tweezers.
The special vacuum soldering/ desoldering
equipment is recommended
do a lot of chip replacements. Otherwise, it is
usually possible to remove and replace chip
components with only a tapered, temperature
controlled soldering iron, a set of tweezers and
braided copper solder wick. Soldering iron
temperature should be below 280 °C
Precautions for Chip Replacement
K
K
K
Removing Chip Components
D
you expect to
if
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°F).
(536
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Do not disconnect a chip forcefully, or the
foil pattern may peel off the board.
Never re-use a chip component. Dispose of
all removed chip components immediately
to avoid mixing with new parts.
Limit soldering time to
a void damaging the component and
board.
Remove the solder at each joint, one joint at
a time, using solder wick whetted with non
acidic flux as shown below. Avoid a pp lying
pressure, and do not attempt to remove the
tinning from the chip's electrode.
Grasp the chip on both sides with tweezers,
and gently twist the tweezers back and
f o rth (to break the adhesive bond) while
alternately heating each electrode. Be care
ful to avoid peeling the foil traces from the
board. Dispose of the chip when removed.
After removing the chip, use the copper
braid and soldering iron to which away any
excess solder and smooth the land f o r in
stallation of the replacement part.
seconds or less to
3
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