Motorola RADIUS GP300 Service Manual download pdf (Page 17)

Repair Procedures and Techniques — General 3-3

4.0 Repair Procedures and Techniques — General

Parts Replacement and Substitution

When damaged parts are replaced, identical parts should be used. If the identical replacement part

is not locally available, check the parts list for the proper Motorola part number and order the part

from the nearest Motorola Communications parts centre listed in the “Piece Parts” section of this

manual.

Rigid Circuit Boards

This family of radios uses bonded, multi-layer, printed circuit boards. Since the inner layers are not

accessible, some special considerations are required when soldering and unsoldering components.

The printed-through holes may interconnect multiple layers of the printed circuit. Therefore, exercise

care to avoid pulling the plated circuit out of the hole.

When soldering near the 20-pin and 40-pin connectors:

Avoid accidentally getting solder in the connector.

Be careful not to form solder bridges between the connector pins.

Examine your work closely for shorts due to solder bridges.

Flexible Circuits

The flexible circuits are made from a different material than the rigid boards, and require different

soldering techniques. Excessive prolonged heat on a flexible circuit can damage the material.

Therefore, avoid excessive heat and excessive bending.

For parts replacement, use the ST-1087 Temperature-Controlled Solder Station with a 600-700

degree tip, and use small diameter solder such as ST-633. The smaller size solder will melt faster

and require less heat to be applied to the circuit.

To replace a component on a flexible circuit:

1. Grasp with seizers (hemostats) the edge of the flexible circuit near the part to be removed.

2. Pull gently.

3. Apply the tip of the soldering iron to the component connections while pulling with the seizers.

5.0 Disassembling and Reassembling the Radio — General

Since these radios may be disassembled and reassembled with the use of only four (board to

casting) screws, it is important to pay particular attention to the snaps and tabs, and how parts align

with each other.

The following tools are required for disassembling the radio:

Small flat blade screwdriver

penknife-size screwdriver

TORX™ T6 screwdriver

NOTE

Do not attempt to puddle-out components. Prolonged application of heat may damage the

flexible circuit.

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Motorola RADIUS GP300 Service Manual Page 17