AN/ARC-5 Handbook

							3--6. TRANSMITTER ALIGNMENT. 
 
3--7. PRELIMINARY INSTRUCTIONS. 
Bench Setup- Connect transmitter, with outer shield removed, to AN/GRM-1, as shown in figure 1--3. 
Frequency Meter -- LM-13 -- Couple as indicated in Transmitter Alignment Chart, (See figure 3--3.). 
 
3-8. TRANSMITTER ALIGNMENT NOTES. 
 
3--9. Zero-beat should occur at mid-position of E-62. If it is impossible to obtain a zero-beat with E-62, 
C-60 may be unlocked from its normal locked position and adjusted to give a zero-beat with E-62 at 
mid-position. 
 
3-10. To correct frequency error at the low end, transmitter FREQUENCY by over-shooting the correct 
setting an amount one-half that of the error. Adjust E-58 for zero-beat. Reset FREQUENCY to correct 
setting and retrim C-60 for zero-beat. The reason for the latter operation is to achieve accuracy at the 
high and low frequency points with a minimum number of steps. 
 
3-11. To correct the tracking error, E-59 should be adjusted at the low frequency and by over-shooting 
by one-half the number of turns necessary to obtain minimum plate current.TRANSMITTER 
ALIGNMENT CHART (See figures 3--4 and 3--5.) 
 
STEP CONNECTIONS 
ON TS-58/GRM-
1 DIAL SETTING TRANSMITTER 
OPERATION ADJUST 1 Connect 
Phantom 
Antenna to 
transmitter 
antenna post.    Turn transmitter ON. 
Key transmitter. 
Check 
FREQUENCY 
against crystal 
frequency by tuning 
for greatest shadow 
on resonance 
indicator. FREQUENCY 
knob 2 
  T-18 2.9 mc  
T-19 3.9 mc  
T-20 5.2 mc  
T-21 6.9 mc  
T-22 9.0 mc  Turn FREQUENCY 
dial to setting 
indicated; Emission 
switch to VOICE. 
Key transmitter. 
Load transmitter by 
adjusting for 
maximum antenna 
current. ANT IND.  
ANT COUP. 3 Frequency meter 
loosely coupled 
to dummy load 
and set to same 
frequency.  Same as Step 2.  Adjust master 
oscillator trimmer for 
zero-beat in 
frequency meter 
headphones. (See 
Transmitter 
Alignment Notes, 
paragraph 3--9.) E-62 4 Same as Step 3.  
T-18 2.2 mc  Turn FREQUENCY 
dial to setting 
indicated. Vary E-58  
						

							T-19 3.1 mc  
T-20 4.1 mc  
T-21 5.4 mc  
T-22 7.1 mc FREQUENCY dial 
for zero-beat and 
note error. To 
correct, adjust 
master oscillator 
inductance. (See 
Transmitter 
Alignment Notes, 
paragraph 3--10.) 5 Repeat Steps 3 and 4 until the final setting of E-62 with to cover in place is at a mid-
position and dial setting at the high and low is accurate. Dial setting should be within 
0.03 per cent of actual frequency as indicated by LM frequency meter. 6 Remove Phantom Antenna 
to align R-F amplifier. 
Remove frequency meter 
and coupling. TS-58/GRM-I 
switch to position 5. Same as Step 
2.  Adjust for 
minimum R-F 
amplifier plate 
current, which 
should be 
below 10 
divisions (25 
ma) on TS-
58/GRM-1 
meter. C-67 (normally 
locked) 7 
  Same as Step 
4.  Turn 
FREQUENCY 
dial to setting 
indicated to 
check 
tracking; note 
if the minimum 
R-F plate 
current is 
within 10 ma 
of the 
minimum 
obtained in 
Step 6. To 
correct, adjust 
iron core. (See 
Transmitter 
Alignment 
Notes, 
paragraph 3--
1 l.)   8 Repeat Steps 6 and 7 until R-F amplifier is operating at minimum plate current at the 
high frequency end and until tracking error is corrected. 9 Reconnect Phantom 
Antenna to transmitter 
antenna post.    Adjust 
transmitter for 
maximum 
antenna 
current output. 
Lock all dial 
controls at 
completion of 
this check. ANT IND. 
ANT COUP.  
						

							SECTION IV TROUBLE ISOLATION  
Figure 4-1. Typical Communications Receiver, Bottom View  
Figure 4-2. Typical Receiver, Top View Inside, and Bottom View Dynamotor  
						

							4--1. RADIO RECEIVER. 
 
4--2. DYNAMOTOR UNIT.4--3. PRELIMINARY INSTRUCTIONS: All tests on the receiver will be 
performed using the AN/GRM-1 Test Setup, as shown in figure 1--3. 
 
STEP TEST 
POINT TEST 
EQUIPMENT 
CONTROLS NORMAL INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1. A Control switch to 
MCW or CW 
position. Meter 
switch to position 
3. Dynamotor scans; I-
104-A meter indicates 
from 46 to 50 (230 to 
250 volts dc):  Shorted or open 
dynamotor windings; 
defective plugs or 
jacks; open choke L-
14, L-15. 2. B Control switch to 
MCW or CW 
position. Meter 
switch to position 1 
and 2. Position 1; meter reads 
56 (28 volts dc). 
Position 2; meter reads 
14 to 17 (1.4-1.7 amps). Blown fuses; 
defective plugs or 
jacks; open wiring, 
shorted or open 
dynamotor windings.  
4--4. AUDIO-FREQUENCY CIRCUIT. 
(See chart below.) 
 
4--5. PRELIMINARY INSTRUCTIONS: Set Audio Signal Generator to 1000 cycles, zero output. 
Connect TS-375/U or TS-352/U a-c test leads across Audio Signal Generator output terminals. 
Connect the other pair of test leads from Audio Signal Generator output terminals to indicated test 
points and chassis. 
STEP 
TEST 
POINT TEST EQUIPMENT 
CONTROLS ARC-5 
RECEIVER 
CONTROLS NORMAL  
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1 C Set voltmeter on 3 (or 2.5) volt 
a-c range. Advance the output 
level control on Audio Signal 
Generator for 2.25 volt reading 
on voltmeter. Control 
switch to 
MCW 
position.  Output 
meter 
reading of 
200 
miIliwatts or 
greater.  If normal, 
proceed to 
paragraph 4-
-6. If not, 
proceed with 
Step 2, 
paragraph 4-
-5. 2 D Same as Step 1.  Same as 
Step 1.  Same as 
Step 1.  Faulty power 
amplifier 
tube and/or 
circuit 
components, 
Repair and 
return to 
Step 1, 
paragraph 4-
-5 before 
going to 
paragraph 4- 
						

							-6.   
Figure 4-3. Dynamotor Test Points  
						

							Figure 4-4. Audio Frequency Test Points 
4--6. INTERMEDIATE-FREQUENCY CIRCUIT. 
(Follow chart below.)4--7. PRELIMINARY INSTRUCTIONS: Insert a 0.006 ufd capacitor in series with 
the hot lead from the Signal Generator to the receiver. Use a signal modulated 30 per cent at 400 or 
1000 cycles. Connect Signal Generator to indicated TEST POINT. 
 
STEP 
TEST 
POINT TEST EQUIPMENT 
CONTROLS ARC-5 
RECEIVER 
CONTROLS NORMAL  
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1 D Tune the Signal Generator to 
the following appropriate 
frequency. (Rock the Signal 
Generator FREQUENCY dial 
for maximum output meter 
reading.) 
  
  
      UNIT FREQUENCY Output of 10 
milliwatts or 
greater 
across the 
300-ohm 
load, for 
Signal 
Generator 
input as 
follows:     .19-.55 mc 85 kc 310 uv     .52-1.5 mc 239 kc 360 uv     1.5-3.0 mc 705 kc 910 uv     3.0-6.0 mc 1415 kc 330 uv     6.0-9.1 mc 2830 kc Set the 
CONTROL 
switch on 
the I-104-A 
Test Unit to 
MCW 
position. 
430 uv If normal, 
proceed to 
Step 
1,paragraph 
4--8. If not, 
proceed to 
Step 2, 
paragraph 4-
-7. Same output 
as in Step 1. 
Signal 
Generator 
input as 
follows: 8100 uv 7500 uv 10,000 uv 2400 uv 2 1 Same as in Step 1. Same as in 
Step 1. 
2500 uv If normal, 
trouble it in 
converter 
stage. If not 
normal 
proceed to 
Step 3, 
paragraph 4-
-7.  
						

							Same output 
as in Step 1. 
Signal 
Generator 
input as 
follows: 210,000 uv 220,000 uv 130,000 uv 99,000 uv 3 2 Same as in Step 1. Same as in 
Step 1. 
85,000 uv If normal, 
trouble is in 
1st I-F 
stage. If not 
normal, 
trouble is 
probably in 
2nd I-F 
stage. Note 
When a stage is found defective, test the tube in a tube checker and replace with 
good tube if necessary. Conduct routine resistance and voltage measurements to 
locate the defective or faulty component or components within a stage. When trouble 
has been located and corrected, return to Step 1, paragraph 4--7 to determine that I-F 
stages are operating satisfactorily.  
						

							4--8. CONVERTER CIRCUIT.(Follow chart below). 
 
4--9. PRELIMINARY INSTRUCTIONS: Use a signal 50 per cent modulated at 400 or 1000 cycles. 
Connect R-F Signal Generator between the TEST POINT and chassis. When using the VTVM, the d-c 
probe having several megohms of series isolating resistance inserted at its tip should be used. (See 
figures 4--7 and 4--8.) 
 
STEP 
TEST 
POINT TEST EQUIPMENT 
CONTROLS ARC-5 
RECEIVER 
CONTROLS NORMAL  
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1 1 Tune the Signal Generator to 
the following appropriate 
frequency. (Rock the Signal 
Generator FREQUENCY dial 
for maximum output.) Set the 
CONTROL 
switch on the 
I-104-A Test 
Unit to MCW 
position. Output of 10 
milliwatts or 
greater 
across the 
300-ohm 
load, for 
Signal 
Generator 
input as 
follows: Defective 
12K8 tube; 
defective 
circuit 
components; 
improper 
alignment. 
(Proceed to 
step 2 to 
check the 
oscillator 
circuit.) If 
normal, 
proceed to 
step 1, 
paragraph - 
4--10.     UNIT FREQUENCY FREQUENCY NORMAL 
SENS.       .19-.55 mc .55 mc .55 mc 370 uv 
      .52-1.5 mc 1.5 mc 1.5 mc 430 uv 
      1.5-3.0 mc 3.0 mc 3.0 mc 990 uv 
      3.0-6.0 mc 6.0 mc 6.0 mc 390 uv 
      6.0-9.1 mc 9.1 mc 9.1 mc 480 uv 
  2 2 Set VTVM to 12-volt d-c 
range, negative polarity. 
Connect d-c probe to TEST 
POINT. Vary the 
frequency 
from the high 
end to the low 
end of the 
dial. VTVM 
indicates a -
6 to -9 volts. 
This voltage 
varies over 
the 
frequency 
range.  Weak or 
defective 
oscillator 
section of 
12K8 
converter 
tube. 
Defective 
components. 
Improper 
alignment.  
						

							4--10. RADIO-FREQUENCY CIRCUIT. 
( Follow chart below). 
STEP 
TEST 
POINT TEST EQUIPMENT 
CONTROLS ARC-5 
RECEIVER 
CONTROLS NORMAL  
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1 1 Same as Step 1, paragraph 
4--8. Control to 
MCW Loud clear 
tone.     UNIT FREQUENCY FREQUENCY NORMAL 
SENS.     .19-.55 
mc .55 mc .55 mc 50 uv      .52-1.5 
mc 1.5 mc 1.5 mc 80 uv     1.5-3.0 
mc 3.0 mc 3.0 mc 150 uv     3.0-6.0 
mc 6.0 mc 6.0 mc 130 uv     6.0-9.1 
mc 9.1 mc 9.1 mc 100 uv R-F tube or 
circuit. If 
normal 
proceed to 
Step 1, 
paragraph 4-
-11.  
 
4--11. ANTENNA CIRCUIT. 
(Follow chart below). 
STEP TEST 
POINT TEST EQUIPMENT 
CONTROLS ARC-5 
RECEIVER 
CONTROLS NORMAL 
INDICATION POSSIBLE 
CAUSES OF 
ABNORMAL 
INDICATION 1. E Same as Step 1, paragraph 
4--8 Control to 
MCW Loud clear 
tone in 
headset.     UNIT FREQUENCY FREQUENCY NORMAL 
SENS.     .19-.55 mc .55 mc .55 mc 5 uv     .52-1.5 mc 1.5 mc 1.5 mc 7 uv     1.5-3.0 mc 3.0 mc 3.0 mc 7 uv     3.0-6.0 mc 6.0 mc 6.0 mc 6 uv     6.0-9.1 mc 9.1 mc 9.1 mc 6 uv Antenna 
circuit. If 
normal, this 
completes 
the receiver 
check.