Elenco DataCom Tester Kit - Manual (Page 4)

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CONSTRUCTION
Introduction
The most important factor in assembling your TCT-255 Multi-Netwok Cable Tester Kit is good
soldering techniques. Using the proper soldering iron is of prime importance. A small pencil
type soldering iron of 25 - 40 watts is recommended. The tip of the iron must be kept clean
at all times and well tinned.
Solder
For many years leaded solder was the most common type of solder used by the electronics
industry, but it is now being replaced by lead-free solder for health reasons. This kit contains
lead-free solder, which contains 99.3% tin, 0.7% copper, and has a rosin-flux core.
Lead-free solder is different from lead solder: It has a higher melting point than lead solder, so
you need higher temperature for the solder to flow properly. Recommended tip temperature is
approximately 700
O F; higher temperatures improve solder flow but accelerate tip decay. An
increase in soldering time may be required to achieve good results. Soldering iron tips wear
out faster since lead-free solders are more corrosive and the higher soldering temperatures
accelerate corrosion, so proper tip care is important. The solder joint finish will look slightly
duller with lead-free solders.
Use these procedures to increase the life of your soldering iron tip when using lead-free
solder:
• Keep the iron tinned at all times.
• Use the correct tip size for best heat transfer. The conical tip is the most commonly used.
• Turn off iron when not in use or reduce temperature setting when using a soldering station.
• Tips should be cleaned frequently to remove oxidation before it becomes impossible to remove.
Use Dry Tip Cleaner (Elenco ® #SH-1025) or Tip Cleaner (Elenco ® #TTC1). If you use a sponge to
clean your tip, then use distilled water (tap water has impurities that accelerate corrosion).
Safety Procedures
• Always wear safety glasses or safety goggles to protect your eyes when
working with tools or soldering iron, and during all phases of testing.
• Be sure there is adequate ventilation when soldering.
• Locate soldering iron in an area where you do not have to go around it or reach over it. Keep
it in a safe area away from the reach of children.
• Do not hold solder in your mouth. Solder is a toxic substance. Wash hands thoroughly
after handling solder.
Assemble Components
In all of the following assembly steps, the components must be installed on the top side of the
PC board unless otherwise indicated. The top legend shows where each component goes.
The leads pass through the corresponding holes in the board and are soldered on the foil side.
Use only rosin core solder.
DO NOT USE ACID CORE SOLDER!
Heat Sinking
Electronic components such as transistors,
IC’s, and diodes can be damaged by the heat
during soldering. Heat sinking is a way of
reducing the heat on the components while
soldering. Dissipating the heat can be
achieved by using long nose pliers, an alligator
clip, or a special heat dissipating clip. The heat
sink should be held on the component lead
between the part and the solder joint.
Heat Sink (this can be ordered as part of Elenco ® ’s Solder
Ease Kit Model SE-1).
Soldering Iron
Solder
Heat Sensitive
Component (Diode)
PC Board
Figure 6