Troubleshooting Chart-continued

TM 11-5820-509-35

Item

Indication

Probable trouble

Procedure

Multimeter at A5J7 (fig. 3-4) does

Popover control relay circuits of R1

Proceed to popover distribution

not read +24 volts dc.

or K2, or low voltage circuits of

circuit checks (para 3-5b).

PP-3518/PRC 47 (A51 are

defective.

Multimeter at A5J8 (fig. 3-4) does

Low-voltage power circuits or

Proceed to power distribution

not read +20 volts dc regulated.

regulator of PP-3518/PRC-47

circuit checks (para 3-5b ).

(A5) are defective.

Multimeter with rf probe at A3J5

Signal Data Translator CV-

Proceed to frequency generation

(fig. 3-4) does not read 1.75

1377A/PRC-47 (A3) defective.

circuit checks (para 3-5b).

volts peak-to-peak.

Frequency counter at A3J5 does

Signal Data Translator CV-

Proceed to frequency generation

not read 3502 kHz.

1377A/PRC-47 (A3) defective.

circuit checks (para 3-5c ).

Place POWER-LIGHTS switch on the front of RT-671/PRC-47 to POWER OFF. Connect test equipment for receiver tests (fig.

3-2). Adjust frequency control knobs for reading of 2225 on KILOCYCLES indicator. Adjust signal generator output level to

2.0 microvolts at 2226 Hz. On RT671/PRC-47, rotate VOLUME control to maximum clockwise stop, then place POWER-

LIGHTS switch to POWER ON.

Multimeter with rf probe at A2J3

Signal Data Translator CV-

Proceed to receiver circuit checks

(fig.. 3-4} does not read 100

1377A/PRC-47 (A3) defective.

(para 3-5d ).

micro-volts rms.

Multimeter with rf probe at A2J4

Radio Frequency Oscillator 0-

Proceed to frequency generation

(fig. 3-4) does rot read 1.5 volts

1032/PRC-47 (A6) defective.

and/or relay circuit checks (para

rms.

3-5c and/or 3-5f ).

Multimeter with rf probe at A1J13

Amplifier-Modulator AM-

Proceed to receiver circuit checks

(fig. 3-4) does not read 0.1 volt

3507/PRC-47 (A2) defective.

(para 3-5d).

rms (1000 Hz approx.)

CAUTION

Before proceeding further, disconnect signal generator and dummy load from ANTENNA

terminal. Place POWER-LIGHTS switch on the front of RT-671/PRC-47 tom POWER OFF.

Connect the test equipment for transmitter tests (fig. 3-3). Set KILOCYCLES indicator on the

front of RT-671/PRC-47 to 2000. Return POWER-LIGHTS switch to POWER ON, and tune the

power amplifier as follows:

CAUTION

Do not permit the OPR-TUNE switch to remain in TUNE position for more than a few seconds at a

time while the output circuit is being adjusted. Circuit damage can result.

(3) Return the OPR-TUNE switch to OPR.

(1) Place OPR-TUNE switch to TUNE.

Connect audio oscillator to A1J1 (fig. 3-4) and set the

(2) Immediately adjust POWER AMPLIFIER

output level to 0.1 volt rms at 1, 000 Hz.

TUNE controls for maximum indication on XMTR

OUTPUT meter.

Item

Indication

Probable trouble

Procedure

CAUTION

Do not permit CW-FSEC/VOICE switch to remain in the CW-FSK position for mere than a few at a time; output circuit dodge

can result.

With CW-FSK/VOICE switch to

High-voltage power supply circuits

Proceed to power distribution

CW-FSK, multimeter at J101

of PP-3618/PRC-47 (A5)

circuit checks (para 3-5b).

(fig 3-5) does not read +65

defective.

volts dc.

Multitester with rf probe at an-

Amplifier-Modulator AM-

Proceed to transmitter circuit

tenna simulator does not read

3507/PRC-7 (A2), or

power checks (para 3-5e ).

13.7 volts rms with CW-

amplifier stage defective.

FSK/VOICE switch at CW-

FSK.

NOTE

place CW-FSK/VOICE switch to VOICE, rotate XMTR PWR switch to Hi, and retune the output

circuit to peak the XMTR OUTPUT meter readings.

3-74