User's Manual

3.6 Introduction To Servicing
M889-00
02/10/95 Copyright TEL
3.3 Component Replacement
3.3.1 Leaded Components
Whenever components are removed from or fitted to the PCB, care must be taken to
avoid damage to the track. The two satisfactory methods of removing components from
PTH PCBs are detailed below.
Note:
The first method requires the use of a desoldering station, e.g. Philips SBC
314 or Pace MBT-100E.
3.3.1.1 Desoldering Iron Method
Place the tip over the lead and, as the solder starts to melt, move the tip in a circu-
lar motion.
Start the suction and continue the movement until 3 or 4 circles have been com-
pleted.
Remove the tip while continuing suction to ensure that all solder is removed from
the joint, then stop the suction.
Before
pulling the lead out, ensure it is not stuck to the plating.
If the lead is still not free, resolder the joint and try again.
Note:
The desoldering iron does not usually have enough heat to desolder leads
from the ground plane. Additional heat may be applied by holding a sol-
dering iron on the tip of the desoldering iron (this may require some addi-
tional help).
3.3.1.2 Component Cutting Method
Cut the leads on the component side of the PCB.
Heat the solder joint
sufficiently
to allow
easy
removal of the lead by drawing it
out from the component side: do
not
use undue force.
Fill the hole with solder and then clear with solderwick.