General Parts Replacement Techniques

TM 11-5820-509-35

NOTES:

1. SWITCH SHOWN IN XMTR PWR LOW POSITION.

2. SWITCH VIEWED FROM REAR, WITH DRIVE END AT TOP.

3. CIRCLED NUMBERS ARE CALLOUTS ON XMTR PWR SWITCH EXPLODED VIEW.

TM 5820-509-35-108

Figure 3-93. Radio Receiver-Transmitter RT-671/PRC-47, Power Amplifier Compartment, XMTR PWR Switch

(S103) (A8A4A1), Connection Diagram.

Section IV. REPAIR

3-8. General Parts Replacement Techniques

(2) A pencil-type, 25-watt soldering iron is

recommended for removal and replacement of

semiconductor devices (transistors, diodes, zeners,

a. Moat component parts of Radio Set AN/PRC-47

varicaps, etc.). When alternating current is used to heat

are readily accessible by removing the malfunctioning

the soldering iron, an isolation transformer is

module, then its card assembly, and finally the defective

recommended to reduce the possibility of electrical

component. Those mechanical and electrical repairs

transients being induced into the circuit, or a polarity

that require extensive disassembly of the equipment are

difference from existing between the soldering iron and

best performed in well-lighted, uncluttered, and

the component being soldered.

reasonably clean surrounds.

b. The following general precautions apply in

CAUTION

performing repair procedures on the AN/PRC-47.

Always check the soldering iron for

short-circuits to the tip before using

(1) When soldering or unsoldering precision

it.

Do not use a soldering gun

resistors, transistors, or other semiconductor devices,

because damaging voltages can be

solder quickly to reduce the heat conduction to as low as

induced into the component.

amount as possible. When space limitations permit, use

a heat sink between the solder joint and the component

(3) When replacing a component, particularly

being soldered.

those in the tuned circuits and frequency

3-95