EQUIPMENT REPORTS from
Electronics Now Magazine (Jan. 1994)
It would be surprising to find a reader of this
magazine who was not well versed in the fine art of
soldering. But desoldering is another matter entirely.
It seems as if every technician has his own favorite
method. The DEN-ON SC-7000 desoldering tool seems to
provide the right mix of features for everything from
removing through-hole components from 12-layer boards to
removing surface-mounted devices. It is available from,
among other distributors,
Instruments (974 SE Pioneer Rd., El Dorado, KS
Technicians who need to desolder components only
occasionally often find that the fastest and easiest way
to go is a simple hand-operated spring-loaded vacuum
tool. Desoldering braid is another favorite for
low-volume desoldering. Higher-volume
applications--where many circuit boards need to be
reworked in an efficient, cost-effective manner--often
require a full service/rework center with multiple
soldering irons and desoldering tools.
The SC-7000 desoldering tool is unique in that it
plugs directory into an AC outlet and is self-contained.
No bench-top vacuum pump and connection hoses are
required because the diaphragm pump is integrated into
the handheld unit. The direct in-line connection between
the pump and the tip provides such efficiency that
8-layer boards can be worked. That increases to 12
layers if the bottom side is preheated. The rated vacuum
is 600 mm Hg, and the rated air flaw rate is 15 liters
per minute with an open tip. The maximum vacuum can be
reached in 0.2 seconds.
The SC-7000 is a gun-shaped device, measuring at its
widest dimensions about 7 x 7 1/2 x 1 3/4 inches. It
weighs less than one pound. The black plastic housing
contains carbon, which helps to prevent damage to
sensitive components form electrostatic discharge or
A rotary temperature control is located on the rear
end of the gun. It can be adjusted from 300 degrees
Celsius to 400 degrees Celsius (525 degrees Fahrenheit
to 842 degrees Fahrenheit). Above the temperature
control is an indicator lamp that remains steady as the
tool comes up to operating temperature, and that blinks
when the desired operating temperature is reached. If
the temperature setting is reduced, the indicator
remains unlit until the tip reduces to the new, reduced
temperature. The tool heats up quickly, reaching its
midpoint temperature (375 degrees Celsius) in about 2
minutes, and it also has a quick recovery time.
A power switch for the unit is located at the butt
end of the gun, and a trigger for the vacuum pump is at
the customary trigger location for a gun.
There are two other sets of controls on the SC-7000.
First is a mechanical toggle that switches the
desoldering tool between its section and its hot-air
blow function. Another set of mechanical controls are
used to change the two-piece filter cartridge which
mounts behind the tip, above the trigger.
The filter cartridge design is effective in
maximizing the life of the filter. Most of the solder
and flux removed accumulates on a hard plastic base that
is in front of the fibrous filter. When the cartridge is
full, it is simply thrown away. Replacement filter
cartridges cost about $5 each.
To remove surface-mounted components, a hot-air tip
and hot-air filter cartridge are required. Tips can be
changed easily with the small open-ended wrench supplied
with the desoldering tool. An
SMD accessory kit
is recommended. It includes not only the hot-air blower
nozzle and filter, but also stainless-steel wire and
blades, and holders for the wire and blades, all of
which make SMD removal possible.
Surface-mounted devices can be removed in several
ways with the hot-air blower. One method is to slip some
stainless-steel wire under the legs of an IC, forming a
loop. The wire is thin used to lift the legs as the
blower melts the solder that holds them to the circuit
Another method is to insert a short length of
stainless steel wire into the wire holder. As each lead
is heated, the wire can be slipped under the lead,
lifting it from the board. With a little practice, it is
possible to desolder individual leads of a flat pack or
The stainless steel blade can be used in a similar
manner to remove PLCCs (plastic leaded chip carriers)
and chip resistors and capacitors from circuit boards.
The SC-7000 is available from
Instruments, Inc. for $395.00, which includes a
convenient stand for bench-top use, and a cleaning pin
set. An SMD removal
kit, which includes a hot-air blower tip and other
required materials, is available for $42.00.
Any technician who needs quality desoldering
capability but who canít justify the purchase of a
bench-top desoldering service center will be well served
by the DIC SC-7000 desoldering tool.