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PROCESSOR TECHNOLOGY CORPORATION
8KRA STATIC READ/WRITE MEMORY MODULE
APPENDIX III
SOLDERING TIPS
(1)
Use a low-wattage iron — 25 watts is good. Larger irons run the
risk of burning the printed-circuit board. Don ' t try to use a solder
ing gun, they are too hot.
(2)
Use a small pointed tip and keep it clean. Keep a damp piece of
sponge by the iron and wipe the tip on it after each use.
(3)
Use 60-40 rosin-core solder ONLY. DO NOT use acid-core solder
or externally applied fluxes. Use the smallest diameter solder you
can get.
NOTE: DO NOT PRESS THE TOP OF THE IRON ON THE PAD
OR TRACE. THIS WILL CAUSE THE TRACE TO "LIFT" OFF OF
THE BOARD WHICH WILL RESULT IN PERMANENT DAMAGE.
(4)
In soldering, wipe the tip, apply a light coating of new solder to it,
and apply the tip to both parts of the joint, that is, both the component
lead and the printed-circuit pad. Apply the solder against the lead and
pad being heated, but not directly to the tip of the iron. Thus, when
the solder
melts the rest of the joint will be hot enough for the solder
to " take," (i.e., form a capillary film).
(5)
Apply solder for a second or two, then remove the solder and keep
the iron tip on the joint. The rosin will bubble out. Allow about three
or four bubbles, but don't keep the tip applied for more than ten
seconds .
(6)
Solder should follow the contours of the original joint. A blob or lump
may well be a solder bridge, where enough solder has been built
upon one conductor to overflow and "take" on the adjacent conductor.
Due to capillary action, these solder bridges look very neat, but they
are a constant source of trouble when boards of a high trace density
are being soldered. Inspect each integrated circuit and component
after soldering for bridges.
(7)
To remove solder bridges,it is best to use a vacuum "solder puller"
if one is available. If not, the bridge can be reheated with the iron
and the excess solder "pulled" with the tip along the printed circuit
traces until the lump of solder becomes thin enough to break the bridge.
Braid-type solder remover, which causes the solder to "wick-up"
away fromtthe joint when applied to melted solder, may also be used.
AIII-1
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