Yaesu FT-8100R Technical Supplement page 6

Chip Component Information - - - - - - - - -
Replacing Chip Comp onents
Chip components are installed. at the factory
by a series of robots. The first one places a small
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 applied
and the boa rd is then ba ked to ha rden the resin
and flow the solder. For double sided boa rds, no
so lder paste is a p p lied, but the bo ard is baked
(or exposed to ultra-violet light) to cu re the re sin
be fore di p so lderi ng .
In o ur la boratories and service sho ps, sma ll
quantities of chip components are mounted ma n-
ually by applying a spot of resin, placing with
tweezers,
and then soldering by very small dual
streams of hot air (without physical contact dur-
ing soldering). We remove parts by first remov-
ing 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/dcsclde ring equipment
is rec ommend ed if yo u expect to do a lot of chip
re placem ents. O therwise, it is usua lly possib le
to remove a nd repla ce chip co m po nen ts w it h
on ly a ta pe re d, tempera ture-con trolled solde r-
in g iron, a se t o f tweezer s a nd brai ded copper
solder wic k. Soldering iron te mpera ture sho uld
be below 280°C (536°8.
1-4
Precautions for Chip Repla cement
o
Do not disconnect a chip forcefully, or the
foil pattern may peel off the board .
o
Never re-use a chip component. Dispose of
all removed chip components immediate-
ly to avoid m ixing with new parts.
o
Lim it soldering time to 3 seconds or less to
avoid damaging tile component an d board .
Removing Chi p Components
o
Remove the solde r at each joint, one joint at a
ti me, u sing so lder wic k w hetted w it h non a-
cid ic fluxes as shown be low. Avoid applying
pressure, and do not attempt to re move tin-
ning from the chip's electrode.
o
G rasp the chip on bot h sides with tweezers,
and ge nt ly twist the tweezers back and fort h
(to break the ad hesive bond) while alternate-
ly hea ting each electrod e. Be careful to avoid
pe elin g the foil traces from the boa rd .
Dispose of th e chip w hen removed.
o
After rem oving tile ch ip, use th e copper braid
and soldering iron to wic k away any excess
solde r and smooth the land for installation of
the replacement part.
IT-B lOOR Tuhn icaf Suppl emNl t
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