Table of Contents
Advertisement
6-4 PCB Inspection
6-4-1 Cautions for Part Replacement
1.
The human body carries much static electricity. Before
touching a part for repair, replacement or the similar
purpose, be sure to touch a grounded metallic portion by
hand to let the static electricity go through the metallic
portion to the earth.
Especially when handling any micro computer or IC,
carefully remove such static electricity before touching
them.
2.
When repairing any part on a work bench, be sure to
place an insulative sheet on the bench and always keep
the sheet surface neat without any metal fragments.
If any such fragment touches a part, a secondary trouble
will possibly be caused in the part.
3.
Before replacing any parts, be sure to turn off the power
supply. If such replacement is done with the power supply
kept on, an electric shock, short circuit or destruction of a
part may result.
4.
During replacement or repair of a part, carefully handle it
: The printed circuit board has fine lead wires (jumper
wires) and glass-made parts (diode) on its substrate.
So if a circuit board is roughly handled, such
lead wires and parts will be easily broken or damaged by
bending or shock.
6-4-2 Procedure
The parts should be replaced in the following procedure.
Check for any faulty part.
Detach the faulty part.
Replace it with a new part.
Check the operation of the new part.
The repair is completed.
50
5.
When soldering the lead wires of any new part, be sure
to polish them using an emery paper or the like before
soldering them.
Since the lead wires of any new part are covered with an
oxide film, solder cannot adhere to the lead wires if not
polished.
6.
When soldering any part, care should be exercised not to
apply any high-wattage soldering iron to the part for a
long time. Some parts are of so low a heat resistance
that they may be broken or have the properties changed
if a soldering iron is so applied (Otherwise, the pattern
may possibly be separated and raised).
7.
The heat of the soldering iron should be transferred to
the entire object to be soldered. If the solder pieces are
not well fused due to insufficient transfer of the heat from
the soldering iron, no satisfactory electrical continuity can
be assured even if the soldered objects appear well con-
nected to each other.
8.
The solder used should be limited to a minimum.
If excessive solder is used, it will cause inter-pattern
contact, which may cause malfunction of the circuit.
Samsung Electronics
Hide quick links:
Advertisement
Table of Contents
