TM 11-242 Radio set SCR-300-A 1945

TABLE OF CONTENTS 
SECTION I Description 
General 1 
Radio Set SCR-300-A, Components, with Weights and Dimensions 2 
Range 3 
Frequency Coverage 4 
Power Source 5 
Power Input 6 
Power Output 7 
Weight 8 
Description of Main Components 9 
SECTION II Installation and Operation 
Initial Procedure 10 
Installation 11 
Preparation for Use 12 
Operation 13 
General Operating Instructions and Precautions 14 
SECTION III Functioning of Parts 
Receiver 15 
Transmitter 16 
SECTION IV Maintenance 
Locating Trouble 17 
Battery Replacement 18 
Servicing 19 
Tube Replacement 20 
Dial Light Replacement 21 
Alignment 22 
Adjustment of Replaced Coils 23 
Replacement of Oscillator Coil T 2 24 
Crystal Replacement 25 
Normal Voltage and Resistance Readings 26 
SECTION V — SUPPLEMENTARY DATA 
Parts Location Details 27 
Tabular List of Replaceable Parts 28 
RMA Color Code for Resistors and Capacitors 29 
ILLUSTRATIONS 
Fig. Page 
1 Radio Set SCR-300-A, In Use, Viewed From Right Side 6 
2 Radio Set SCR-300-A, Components 7 
3 Radio Set SCR-300-A In Use, Viewed From Left Side 10 
4 Radio Set SCR-300-A In Use, Showing Antenna AN-131-A 11 
5 Radio Set SCR-300-A In Prone Use, Showing Adjustment of Antenna AN -130- A 12 
6 Antenna AN-130-A, Installation Detail 14 
7 Antenna AN-131-A, Installation Detail 14 
8 Headset HS-30-(*), In Use s 16 
9 Radio Receiver and Transmitter BC-1000-A with Case CS- 128-A, General View 17 
10 Radio Receiver and Transmitter BC-1000-A, Front Panel View 18 
11 Disassembled View Showing Battery Cable Connected to Battery BA-70 22 
12 Disassembled View Showing Battery BA-70 In Place 23 
13 Radio Set Housing Assembly After Battery Installation 24 
14 Radio Set Rear View Showing Assembly of Pad M-391-A, Belt ST-55-A and Strap ST-50-A 26 
15 Harness ST-54-A and Belt ST-55-A, Installation Detail 27 
16 Radio Receiver and Transmitter BC-1000-A, Block Diagram 38 
17 Method of Obtaining Power for Test Purposes 54 
18 Radio Receiver and Transmitter BC-1000-A, Chassis Top View 55 
19 Radio Receiver and Transmitter BC-1000-A, Alignment Instruction Detail, Top View 60 
20 Radio Receiver and Transmitter BC-1000-A, Alignment Instruction Detail, Bottom View 62 
21 Radio Receiver and Transmitter BC-1000-A, Chassis Tube Socket Voltage Diagram 66 
22 Radio Receiver and Transmitter BC-1000-A, Terminal Board Voltage Diagram 67 
23 Radio Receiver and Transmitter BC-1000-A, Chassis Tube Socket Resistance Diagram 69 
24 Radio Receiver and Transmitter BC-1000-A, Terminal Board Resistance Diagram 70 
25 Radio Receiver and Transmitter BC-1Q00-A, Parts Location Diagram Showing Antenna Insulator and CalibrationSwitch Parts 71 
26 Radio Receiver and Transmitter BC-1000-A, Parts Location Detail, Showing Jack Waterseal Assembly, Volume and Squelch Controls 71 
27 Case CS-128-A, Parts Location Detail 72 
28 Radio Receiver and Transmitter BC-1000-A, Chassis Bottom View Showing Location of Major Parts 73 
29 Outline Dimensional Detail 74 
30 Battery Cable Wiring Diagram 75 
31 Radio Receiver and Transmitter BC-1000-A, Parts Location Diagram Showing Dial Mechanism Parts 76 
32 Radio Receiver and Transmitter BC-1000-A, Pictorial Wiring Diagram Showing Location of Resistors and Chokes 77 
33 Radio Receiver and Transmitter BC-1000-A, Pictorial Wiring Diagram, Showing Location of Capacitors 78 
34 Radio Receiver and Transmitter BC-1000-A, Schematic Diagram 175