Philips 55PP9401 Service Manual page 20

IC Removal/Replacement
Some chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and
then bent flat against the circuit foil. When holes are the slotted type, the following technique should be
used to remove and replace the IC. When working with boards using the familiar round hole, use the
standard technique as outlined above.
Removal
1. Desolder and straighten each IC lead in one operation by gently prying up on the lead with the
soldering iron tip as the solder melts.
2. Draw away the melted solder with an anti-static suction-type solder removal device (or with solder
braid) before removing the IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and solder it.
3. Clean the soldered areas with a small wire-bristle brush. (It is not necessary to reapply acrylic
coating to areas.)
Small-signal Discrete Transistor Removal/Replacement
1. Remove the defective transistor by clipping its leads as close as possible to the component body.
2. Bend into a U shape the end of each of three leads remaining on the circuit board.
3. Bend into a U shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding leads extending from the circuit
board and crimp the U with long nose pliers to insure metal-to-metal contact, then solder each
connection.
Power Output Transistor Devices Removal/Replacements
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the circuit board.
4. Insert new transistor in circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
7618 General Information page 7