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|  TM 11-5820-509-35
Item
Indication
Probable trouble
Procedure
g.
100 kHz oscillator signal circuit
g.
Check waveform at A6J1.
of radio frequency oscillator A6
Normal reading is 4.5 volts pep
defective.
at a J0 microsecond rate. Repair
100-kHz circuit (para 3-13e) or
replace 0 1032/PRC-47.
h.
1.8 to 0.9 MHz pulse circuit of
oscillator control A7 is defective.
follower Q24 /normal reading 0.6
volts pip at 0.5-microsecond
rate.) Check continuity from J9-
A1 to J10-A1: repair circuit
4311JPRC 47.
i.
Dc error signals from
i.
If voltages not near zero after
discriminator circuit of oscillator
synchronizing, repair
control A7 defective.
discriminator circuit or replace
C-4311 /PRC-47.
j.
Dc error signal circuit or an-
j.
Check continuity from J6-3 to
tilock relay K6 defective.
J11-5 and K6-4: also from J6-2
tp J11-4 and K6-8: verify that
relay K6 operates when a ground
is applied to J11-3. Repair
circuit or replace relay K6 if
defective.
2
KILOCYCLES indicator does not
Frequency generation circuits not
Check the drive mechanism and
track with signal generator.
properly aligned.
align frequency generation
Note: Signal generator should be
circuits.
1-kHz higher than
KILOCYCLES indicator reading
to produce a 1000 Hz audio tone
at the receiver output.
malfunctions to a module within the receiver circuits.
d. Receiver Circuit Tests. Perform the folio wine
procedures in the order listed for isolation of
Item
Indication
Probable trouble
Procedure
Place POWER-LIGHTS switch on the front of RT-671/PRC-47 to POWER OFF. If the procedures of step c have not been
performed immediately prior to these tests, connect the test equipment for receiver tests (fig. 3-2.) Adjust the KILOCYCLES
indicator for a reading of 2225. Adjust the signal generator to 2226 kHz and set its output level to 2.0 microvolts. On RT-
671/PRC-47, set VOLUME control to its maximum clockwise stop, then place POWER-LIGHTS switch to POWER ON.
st
1
No signal at grid of 1 rf am-
a.
T/r relay K101 or circuit to
a.
Check continuity from AN-
plifier A3V1.
antenna terminal defective.
TENNA terminal to K101
(COM). Repair circuit if open.
Check continuity from KI01
(NC) to K101 (COM). Replace
K101 if circuit is open.
b.
Receiver antenna relay K5 or
b.
Check continuity from K101
circuit on main chassis defective.
(NC) to K5 (NC): repair if circuit
is open. Check continuity from
K5 (NC) to K5 (COM): replace
K5 if contacts are open. Check
continuity from K5 (COM) to
J5-A1: repair if defective.
2
No receive input at A2J3 on
a.
Receive circuit of signal data
a.
Repair CV-1377A/PRC-47 (para
amplifier-modulator A2.
translator A3 defective.
3-13c ) or replace module.
b.
Receive if. circuit on main
b.
Check continuity from J6-A2 to
chassis defective.
J4-A2: repair if defective.
c.
Receive if. circuit at amplifier-
c.
Repair AM-3507/PRC-47 (para
modulator input defective.
3-13b ) or replace module.
3
No receive audio at test point
a.
If. amplifier circuits, product
a.
Repair AM-3506/PRC-47 (pare
A1J13 on audio frequency
detector, or af low-pass filter
3-13a ) or replace module.
amplifier A1.
defective.
b.
Receive audio circuit on main
b.
Check continuity from J4-7 to
chassis defective.
J2-23: repair if defective.
3-82
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