Midland Radio SP-300 - Manual (Page 23)

MAXON
SP-300 HAND HELD
Page -20-
May 2001
4. It may be necessary to remove excess solder using a
vacuum de-soldering tool or Solder wick . Again,
use great care when de-soldering or soldering on
the printed circuit boards. It may also be necessary
to remove the epoxy adhesive that was under the
surface mount component and any flux on the
printed circuit board.
Surface Mount Component Replacement
1. “Tin” one terminal end of the new component and
the corresponding pad of the PCB. Use as little sol-
der aspossible.
2. Place the component on the PCB pads, observing
proper polarity for capacitors, diodes, transistors,
etc.
3. Simultaneously touch the “tinned” terminal end and
the “tinned” pad with the soldering iron. Slightly
press the component down on the board as the sol-
der liquefies. Solder all terminals, allowing the
component time to cool between each application
of heat. Do not apply heat for an excessive length of
time and do not use excessive solder.
With a hot-air system, apply hot air until all “tinned” areas
are melted and the component is seated in place. It may be
necessary to slightly press the component down on the
board. Touch-up the soldered connections with a standard
soldering iron if needed. Do not use excessive solder.
z CAUTION: Some chemicals may damage the inter-
nal and external plastic parts of the radio.
4. Allow the component and the board to cool and
then remove all flux from the area using alcohol or
another approved flux remover.
Surface Mounted Integrated Circuit Replacement
Soldering and de-soldering techniques of the surface
mounted IC’s are similar to the above outlined procedures
for the surface mounted chip components. Use extreme care
and observe static precautions when removing or replacing
the defective (or suspect) IC’s. This will prevent any damage
to the printed circuit board or the surrounding circuitry.
The hot-air soldering system is the best method of replacing
surface mount IC’s. The IC’s can easily be removed and
installed using the hot-air system. See the manufacturer’s
instructions for complete details on tip selection and other
operating instructions unique to your system. If a hot-air sys-
tem is not available, the service technician may wish to clip
the pins near the body of the defective IC and remove it. The
pins can then be removed from the PCB with a standard sol-
dering iron and tweezers, and the new IC installed following
the Surface Mount Component Replacement procedures. it
may not be necessary to “tin” all (or any) of the IC pins
before the installation process.