AN/ARC-5 Handbook

							1  FT-227-A MT-70/ARC-5 Mounting for MT-71/ARC-5 
Radio transmitter rack 1  FT-225-A MT-76/ARC-5 Mounting (modulator) 1  FT-229-A MT-77/ARC-5 Mounting (antenna relay unit) 1 Mounting Plate FT-228-A MT-80/ARC-5 Mounting (transmitter control 
C-29/ARC-5 or C-50A/ARC-5) 1  FT-222-A MT-98/ARC-5 Mounting (Receiver control C-
43/ARC-5) 1 Mounting Rack FT-277-A MT-63/ARC-5 Rack for two radio receivers 1  
  MT-71/ARC-5 Rack for two radio transmitters 1 Test Unit I-104-A 
  Test unit for radio receivers 1  TS-
58/GRM-1   Test unit for radio transmitters 1 Cord CD-307-A 
  Headset extension cord 1 Microphone 
  RS-38A Microphone 1 Headset HS-33 
  600-ohm headset (two ANB-
H-1 receivers or equivalent)  
						

							 
Figure 1-4. Cable Assemblies CD 532 and CD 528  
						

							 
Figure 1-5. Cable Assemblies CD 531 and CD 525  
						

							 
Figure 1-64. Cable Assemblies CX-31/GRM-1 and CS-32/GRM-1  
						

							 
Figure 1-74. Cable Assembly CD 527  
						

							NOTES 
 
1. If Antenna relay unit RE-2/ARC-5, being tested, does not have a series capacitor, connect the 
transmitter to TRANS. Connect ANT of the antenna relay unit to terminal A, instead of to terminal 
5, of antenna A-61-A. 
 
2. Test Unit I-104-A normally is used with adapter cord CD-706 as shown. It may be used by attaching 
cord CD-532 to either position of the receiver rack and when so employed, the meter will not indicate 
when the meter switch is in position four or five. Volume control on AVC directly affects sidetone level. 
 
3. The drawing shows the mechanical linkage (Part No. 6151) so that the mechanical tuning features 
of the control units C-26 and C-43/ARC-5 and radio receivers R-20 to R-27/ARC-5 may be tested. No 
linkage is furnished with the test equipment. Control unit MC-257 (local tuning crank) is furnished for 
testing these receivers. 
 
4. Test unit I-104-A may be made to function as a control unit and provide the channel selection when 
testing VHF radio receiver R-28/ARC-5, by connecting cord CD-527 between jack J-103 on the radio 
receiver and jack J-600 on the test unit. 
 
5. Dynamotors *DY-2/ARR-2 and *DY-2A/ARR-2 are furnished with the particular radio receivers as 
shown. Both dynamotors are interchangeable with dynamotors DM-32-A or CBY-21531.  
 
6. Transmitters and receivers may be tested either by direct connection to the test equipment, using 
cords CX-33/GRM-1 and CD-706, or by mounting in a one or two unit rack and using cords CX-
31/GRM-1 and CD-532. 
  
						

							SECTION II PERFORMANCE CHECKS 
 
2--1. GENERAL. 
 
2--2. These PERFORMANCE CHECKS are to be made in the order given; when a performance 
requirement is not met, a reference is made to the appropriate voltage measurement or signal tracing 
procedure in TROUBLE ISOLATION. ALIGNMENT PROCEDURES are included, but are to be used 
only as directed in TROUBLE ISOLATION. Signal tracing techniques are used after voltage readings 
have been found to be normal. The standard maintenance manual should be referred to for detailed 
information concerning the AN/ARC-5 Equipment. 
Note 
Receiver and transmitter PERFORMANCE CHECKS are divided as shown in the 
TABLE OF CONTENTS. 
 
2--3. VISUAL CHECKS. Connect the unit to be checked on the Test Set AN/GRM-1 rack and inspect 
the unit for the following: 
 
l. Faulty plugs, threads and pins. 
2. Improper fusing. 
3. Note evidence of excessive dynamotor ripple at the headset while tuning through the frequency  
    band. 
4. Dirty and chattering antenna relay contacts. 
5. Excessive vibration of the unit in rack. 
Note 
Open filaments can sometimes be detected by noting cold tubes. 
 
2--4. RECEIVER CHECKS. 
 
2--5. D-C POWER SUPPLY AND OPERATING VOLTAGES. 
 
2--6. LIMITS: Input voltage is 27.5 volts dc at 1.7 amps. 
Secondary voltage is 230-250 volts dc at 60 ma. 
 
2--7. PRELIMINARY INSTRUCTIONS: Use Test Set AN/GRM-1, as shown in figure 1-3.  
 
Use Optional Wiring for greater ease in maintenance testing. Do not key the transmitter. Apply d-c 
power and turn the CONTROL SWITCH of Test Set I-104-A to MCW position, allowing the equipment 
time to warm up. Do not remove the cover plates until trouble isolation or alignment is indicated by 
performance failure. Advance INCREASE OUTPUT control to full clockwise position.  
Figure 2-1. Modulation Envelopes  
						

							2--8. TEST PROCEDURE.  
STEP HEAD 
TEST 
SET METER 
SW CIRCUIT 
MEASURED NORMAL 
VALUES NORMAL 
METER 
INDIC. ABNORMAL 
METER INDIC. 1 I-I04-
A 1 Input voltage 27.5 v 56 2 I-I04-
A 2 Input current 1.4-1.7 a 14-17 3 I-I04-
A 3 Plate supply 230-250 v 46-50 4 I-I04-
A 4 Screen 
supply 76-100 v 38-50 5 I-I04-
A 5 Cathode 
current RF 
and 1st IF 
tubes 11-15 ma 44-60 Refer to 
TROUBLE 
ISOLATION 
PROCEDURE, 
Section IV, 
Paragraph 4-1.  
2--9. BAND NOISE.  
 
2--10. LIMITS: (Less than 15 milliwatts.) 
 
2--11. TEST PROCEDURE. 
STEP TEST SET I-1O4-A NORMAL OUTPUT 
INDICATION AND 
CONNECTIONS POSSIBLE 
CAUSES OF 
ABNORMAL 
IND. 1 CONTROL SWITCH to CW or 
MCW. INCREASE OUTPUT control 
to maximum. Connect dummy 
antenna (100 mmfd capacitor) from 
Antenna post to ground. Use short 
leads. Output Meter, OP-
182, and 
headphones 
connected to 
headset jack of 1-
104-A. Switch set to 
600 ohms.   2 Peak receiver ALIGN INPUT 
trimmer for maximum output at the 
high frequency end of dial. Reads less than 1.5 
mw of noise. Check dynamotor 
brushes and 
bearings. 
Replace 
dynamotor, if 
necessary. 3 Turn the receiver frequency dial 
from high to the low end and note 
the maximum noise in the output 
meter. Never exceed 1.5 
mw. Same.   
						

							2--12. SENSITIVITY.  
 
2--13. LIMITS. Less than 10 uv R-F input to obtain 10 mw audio output with INCREASE OUTPUT 
control set at maximum.  
 
2--14. TEST PROCEDURE.  
STEP RECEIVER 
SETTINGS SIG. GEN 
CONNECTIONS OUTPUT INDIC. 
& 
CONNECTIONS NORMAL 
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
IND. 1 FREQUENCY 
at high end; 
MCW 
operation: 
INCREASE 
OUTPUT 
control at 
maximum. Through .006 
mfd capacitor, 
to receiver 
Antenna post. 
Set frequency to 
agree with 
receiver. Output meter, 
OP-182, and 
headphones 
connected to 
headphone jack. 
Set switch to 
600 ohms.       Peak ALIGN 
INPUT 
trimmer. Use modulated 
RF 30 per cent 
at 400 or 1000 
cycles. Maximum 
output. A peak on 
output 
meter.   2 Same as 
Step 1. Vary attenuator 
to obtain 10 mw 
receiver output. Same as Step 
1. 10 uv input, 
or less, to 
obtain 10 
mw audio 
output. Refer to 
TROUBLE 
ISOLATION, 
Section IV, 
paragraphs 4--
4 to 4--11, and 
ALIGNMENT 
PROCEDURE, 
Section 3--1.  3 Same as 
Step 1. 
except switch 
to CW. Rock 
receiver dial 
carefully for 
maximum 
output. Turn 
MODULATION 
switch to OFF. 
Vary attenuator 
to obtain 10 mw 
receiver output. Same as Step 
1. 3.5 uv input 
to obtain 10 
mw output. Check CW 
oscillator and 
ALIGNMENT 
PROCEDURE, 
Section III, 
paragraph 3--
1. 4 Repeat Steps 1 through 3 with receiver dial set at low end.   
						

							2--15. SELECTIVITY. 
 
2--16. PRELIMINARY ADJUSTMENTS: Set the Model 695 output meter to the 1.5 volt range. Connect 
a 300-ohm one-half or one watt composition resistor in parallel with the output meter; connect output 
meter to receiver phone jack. Set the receiver INCREASE OUTPUT control to full counterclockwise 
position. Tune the receiver and the signal generator to the proper frequency, as given in Table below. 
Adjust the signal generator attenuators for 50 microvolts output, 30 per cent modulated at 400 cycles. 
Advance the INCREASE OUTPUT control clockwise until the Model 695 output meter reads 1.0 volts. 
The receiver dial and the ALIGN INPUT trimmer should be adjusted for maximum output meter 
reading. Readjust the INCREASE OUTPUT control as necessary to give output meter reading of 1.0 
volts. Receiver should be set for MCW operation. 
 
STEP OUTPUT METER 
SETTINGS SIGNAL GENERATOR SETTINGS 1 Switch output meter to 15 
volt range. Adjust the output attenuators for 500 microvolts 
output. (Switch MULTIPLIER to 100 position.) 
Slowly detune FREQUENCY dial higher in 
frequency until output meter reads less than 6.O 
volts. 2 Switch output meter to 6 
volt range. Slowly detune FREQUENCY dial higher in 
frequency until output meter reads slightly less 
than 1.5 volts. 3 Switch output meter to 1.5 
volt range. Slowly and carefully detune FREQUENCY dial 
higher in frequency until output meter reads 1.0 
volts. 4 
  Record the amount of frequency deviation from 
original setting at resonance, as given in 
PRELIMINARY ADJUSTMENTS. 5 Repeat Steps 1 through 4. Repeat Steps 1 through 4, detuning the 
FREQUENCY dial lower in frequency. 6 Compare values obtained in Steps 4 and 5; they should be very nearly equal in 
value. Amount of frequency deviation recorded in Steps 4 and should not 
exceed values given in Table below by more than 10 per cent. 7 Repeat Steps I through 5 on the R-23 (.19-.55 mcs.) receiver, with 50,000 
microvolts input, instead of 500. Specifications given in Step 6 also apply. RECEIVER FREQUENCY FREQUENCY DEVIATION EITHER SIDE OF 
RESONANCE R-23 .19-.55 mcs. .19 mcs. 3.0 kcs. 6.0 kcs.*** R-24 .52-1.5 mcs. .52 mcs. 5.0 kcs. R-25 1.5-3.0 mcs. 1.5 mcs. 7.0 kcs. R-26 3.0-6.0 mcs. 3.0 mcs. 15.0 kcs. R-27 6.0-9.0 mcs. 6.0 mcs. 28.0 kcs.