GE BC-375-E, Preliminary Instructions

Page 1: ...PRELIMINARY INSTRUCTIONS FOR RADIO TRANSMITTER BC 375 E AND ASSOCIATED EQUIPMENT Manufactured by GENERAL ELECTRIC COMPANY U S A PUBLISHED BY AUTHORITY OF THE CHIEF SIGNAL OFFICER Order No 16 WFSCPD 42 ...

Page 2: ...r Clamp MC 163 2 9 Interconnection with the Radio Receiver in Aircraft 3 SECTION III PREPARATION FOR USE 10 General 3 11 Radio Transmitter BC 375 E 3 12 Operation at High Altitude 4 13 Dynamotor Unit PE 73 C 4 SECTION IV OPERATION 14 Radio Transmitter Adjustment 4 15 Antenna Adjustments 6 16 Dynamotor Unit PE 73 C 8 17 Reel RL 30 B 8 18 Operating Routine 9 19 Summary Covering Normal Operation 9 SE...

Page 3: ...gram Fig 7 Transmitter Tuning Unit TU 7 B Connection Diagram Fig 8 Transmitter Tuning Unit TU 8 B Connection Diagram Fig 9 Transmitter Tuning Unit TU 9 B Connection Diagram Fig 10 Transmitter Tuning Unit TU 10 B Connection Diagram Fig 11 Transmitter Tuning Unit TU 26 B Connection Diagram Fig 12 Case CS 48 Dimensions and Weight Fig 13 Dynamotor Unit PE 73 C Connection Diagram Fig 14 Dynamotor Unit ...

Page 4: ...are available for use with the radio transmitter Mounting FT 151 A is a tray type and is part of the Radio Transmitter BC 375 E Mounting FT 115 B is a disposable type The tray type mounting to which the radio transmitter is attached by four snap slide catches is normally used The disposal mounting is sometimes added near the top of the radio transmitter to prevent swaying Mounting FT 115 B consist...

Page 5: ...a post on the radio transmitter placing a jumper between LOADING TERMINALS A and B on the radio transmitter and connecting the antenna to terminal B ANT on the antenna tuning unit This alternate connection should be used only if it is necessary to reduce the r f voltages at the radio transmitter because of high altitude flashovers The sensitivity of the radio receiver may be reduced slightly The p...

Page 6: ...grounded and so sup ported that they cannot rub on other cords or metal surfaces In order that the radio receiver used be co ordinated with the radio transmitter the receiver control wires should be connected to terminals 21 and 22 of Plug PL 64 These points are normally closed but are opened when the key is closed and the radio transmitter starts functioning SECTION III PREPARATION FOR USE 10 GEN...

Page 7: ...eet On TONE and VOICE however insulation breakdown may be experienced with Transmitter Tuning Unit TU 8 B 6200 7700 KC above 25 000 feet and with Tuning Unit TU 9 B 7700 10 000 KC above 19 000 feet These altitude limitations may be exceeded slightly by care in tuning and by carefully guarding against accumulation of dust and other foreign matter in the equipment Complete assurance of effective ope...

Page 8: ...ed When finally adjusted the total plate current should read from 200 to 220 milliamperes If necessary detune the antenna circuit slightly keeping the p a dial C in resonance to keep within the plate current limits 6 The equipment is now delivering rated power output and the transmission may be carried on by operating the transmitting key In order to shut down the equipment it is necessary only to...

Page 9: ... port located on the front panel between the TEST KEY and TONE CW VOICE switch insert a screwdriver and rotate the calibration reset capacitor until the transmitter frequency coincides with that of the fre quency meter or standard 5 Close the calibration reset port The transmitter calibration is now reset for any tuning unit of the same order number and serial number as the radio transmitter and t...

Page 10: ...f an antenna depends mainly on its effective length including the ground lead Fundamental frequencies in the range of 2500 7000 kilocycles will be the most common with the usual types of fixed antennas while fundamentals as low as 1500 kilocycles will be obtained with 200 foot trailing wire antennas The antenna tuning equipment in the radio trans mitter is designed to feed antennas at any frequenc...

Page 11: ...one coupling tap will not give sufficient loading while the next higher tap will give overloading of the trans mitter In this case use the higher coupling tap by slightly detuning the antenna circuit and keeping the p a dial C tuned to a minimum plate current until the normal transmitter loading of 210 to 220 milliamperes total plate current is obtained 16 DYNAMOTOR UNIT PE 73 C Starting and stopp...

Page 12: ... no side tone will be supplied in this event Note that the radio frequency and audio frequency tubes are connected in series parallel If one tube is removed another filament will go out 19 SUMMARY COVERING NORMAL OPERATION Although the normal operation of this equipment is extremely simple after the correct installation has been made it is well to study the proper sequence of various equipment pro...

Page 13: ...nna compartment of the radio transmitter At this time inspect the rotating coil in this compartment The winding should be thoroughly cleaned using a clean cloth moistened with naphtha or petroleum spirits c Make certain that all safety wiring is in place that all mounting brackets and supports are rigidly fastened and that all nuts and machine screws are supplied with lockwashers and are tight d D...

Page 14: ...e reel hub and clean off all dirt e Lubricate these points using SAE 10 oil Counter gear shaft bearing 1 drop Main shaft several drops along the bearing surfaces Rear ball bearing on hub adjacent to ratchet teeth 5 drops Front thrust bearing around the edge of the retaining nut at the front end of the hub 5 drops Front ball bearing around the gap between the outside of the hub and the edge of the ...

Page 15: ...r plate current can be de termined on the total plate current meter by remov ing the p a and speech amplifier tubes and placing the transmitter on CW The current indicated should be from 30 to 75 milliamperes depending on the transmitter tuning unit in use 4 Power amplifier plate current may be deter mined by subtracting from the total plate current on CW the currents drawn by the master oscillato...

Page 16: ...l have a mottled appearance which is caused by the formation of a very thin oxide film on the surface of the commu tator bars This film is normal and is not injurious to the commutator or brushes Do not try to remove the oxide film described above A rough or pitted commutator should be smoothed with No 00 or finer sandpaper Never use emery cloth or a file Under normal conditions of operation the l...

Page 17: ...ing the ball bearings it is not neces sary to remove them from the armature shaft Simply immerse the bearing in a shallow pan of clean carbon tetrachloride and wash all of the grease from the bearing The use of a small camel s hair brush will greatly aid the thorough cleaning of the bearing Change the cleaning solvent in the pan as soon as it becomes dirty Always use clean solvent for the final ri...

Page 18: ...TUNING 1170 S 0 1129 TONE V 1 0 1 4 7 AN CW ToV I CW SA VT 1142 Ow CW 1 54 i o 1197C 168 SW2 CD 0 1169 1156 1156 1156 11191 115 0 1192 4 1148 RADIO TRANSMITTER BC 375 E ANTENNA TUNING UNIT BC 306 A DYNAMOTOR UNIT PE 73 G BROWN YELLOW GREEN BLUE RED WHITE ORANGE BLACK KEY KEY 1194 NIC INPUT 011128 MOWN MC SIIMTCH OR KEY T1P WMTE SIDE TONE BLUE KEY RELAY ARM RED KEY RELAY BACK YELLOW 11010 811C OR K...

Page 19: ...163 SUCN TNAT IT MAY SE REMOVED wiTROUT SEMOYiNG OINER ROMS ON SAME TERRIMAL r7 RARELT 8 0 K k P c J1 f 00 6E 69 11 14 5 c eW 7 7 97 36 TS 31 Il e l SE 3 013 T 71 76 30 91 trr 35 1 4 SS 11 io ORANGE 1154 GREEN SR BEEN 4 0 36 ORANGE WO V at GO TS 111 17 8R0 CRANT L E__L0 EE SNEER SLACK ORANGE 116 MIDOL NE RED 183 ACE 112E _ ONE SIDE OF 1103 6401110f 0 SY CONNECTION GREEN L_ r 49 1PLUE PARALLEL SEC ...

Page 20: ... 5 B TU 6 B 14 437 12 437 Tuning Unit and Tubes 49 0 Transmitter Tuning Unit TU 7 B 11 687 Mounting FT 151 A 3 75 Transmitter Tuning Unit TU 8 B 11 437 One Set of Tubes Consisting Transmitter Tuning Unit TU 9 B 11 437 of Four Tubes VT 4 C and Transmitter Tuning Unit TU 10 B 11 437 One Tube VT 25 2 0 Transmitter Tuning Unit TU 26 B 12 750 Fig 3 Radio Transmitter BC 375 E Dimensions and Weights ...

Page 21: ...1 1 1500 3000 K C TU 5 El 1 TU 6 8 3000 4 500 K C TU 9 8 7700 10000 K C 1021 1054 TU 10 8 10000 12500 K C L_ Fig 4 Transmitter Tuning Units TU 5 B TU 6 B TTJ 7 B TU 8 B TU 9 B TU 10 B and TU 26 B Schematic Diagrams ...

Page 22: ...21 PA TANK INDUCTANCE 522 P A BAND CHANGE SWITCH 623 P A FIXED TANK CAPACITOR 524 625 527 P A VARIABLE TANK CAPACITOR 528 ANT COUPLING COIL 529 SWITCH utlIT PIECE Of APPARATUS 102 DIA COPPER WIRE TINNED M NOT MARKED CABLE THESE LEADS START BLACK TAP BLUE TAP 2 BROWN TA 03 GREEN TAP 4 RED TAP 5 ORANGE FINISH ORANGE BLACK 529 522 2 VW_ _ Ora FRONT 527 T 25 TOP 509 I 50 7 501 510 T 516 0 506 515 0 50...

Page 23: ...SYMBOL NAME OF UNIT 601 MO TANK INDUCTANCE 602 MO BAND CHANGE SWITCH 603 MO FIXED TANK CAPACITOR 607 MO VARIABLE TANK CAPACITOR 608 PA GRID CHOKE 609 PA GRID BLOCKING CAPACITOR 610 MO GRID BLOCKING CAPACITOR 611 MO GRID CHOKE 812 NEUTRALIZING CAPACITOR 613 MO COMPENSATING CAPACITOR 114 PkGRID PARASITIC RESISTOR 621 PA TANK INDUCTANCE 622 PA BAND CHANGE SWITCH 623 PA FIXED TANK CAPACITOR 627 PA VAR...

Page 24: ...STENED MECHANICALLY TO TERMINALS BEFORE SOLDERING USE ROSIN CORE SOLDER 520D38 SYMBOL NAME OF UNIT UN 17 7 701 MD TANK INDUCTANCE 702 MA TANK CAPACITOR 703 MA GRID BLOCKING CAPACITOR 704 MA GRID CHOKE 706 PA GRIO BLOCKING CAPACITOR 706 P A GRID CHOKE 707 NEUTRALIZING CAPACITOR 721 R A TANK INDUCTANCE 722 RA TANK CAPACITOR 723 ANT COUPLING CO L 724 ANT COUPLING SWITCH Fig 7 Transmitter Tuning Unit ...

Page 25: ... FASTENED MECHANICALLY TO TERMINALS BEFORE SOLDERING USE ROSIN CORE SOLDER 820038 SYMBOL NAME OF UNIT UNIT4r8 801 MD TANK INDUCTANCE 802 MO TANK CAPACITOR 803 M O GRID BLOCKING CAPACITOR 804 MO GRID CHOKE 805 PA GRID BLOCKING CAPACITOR 808 PA GRID CHOKE 807 NEUTRALIZING CAPACITOR 8 2 I PA TANK INDUCTANCE 822 PA TANK CAPACITOR 823 ANT COUPLING COIL 824 ANT COUPLING SWITCH Fig 8 Transmitter Tuning U...

Page 26: ...ERMINALS BEFORE SOLDERING USE ROSIN CORE SOLDER B20038 SYMBOL NAME OF UNIT UN1T 9 901 M Q TANK INDUCTANCE 902 MO TANK CAPACITOR 903 M 0 GRID BLOCKING CAPACITOR 904 MO GRID CHOKE 905 PA GRID BLOCKING CAPACITOR 906 PA GRID CHOKE 907 NEUTRALIZING CAPACITOR 909 M 0 BY PASS CAPACITOR 9 2 I PA TANK INDUCTANCE 9 2 2 PA TANK CAPACITOR 923 ANT COUPLING COIL 924 ANT COUPLING SWITCH CONNECTION SIZE OF CONNEC...

Page 27: ...H OR ANGEIBLACK FINISH 10 21 T 100 5 TOP BO T TOM END OF THIS CAPACITOR GROUNDED BY M CONNECTION SYMBOL NAME OF UNIT UN IT IO 1001 MO TANK INDUCTANCE 1002 M 0 TANK CAPACITOR 1003 M O GRID BLOCKING CAPACITOR 1004 M O GRIO CHOKE 1005 PA GRID LOCKING CAPACITOR 1006 P A GRID CHOKE 1001 NEUTRALIZING CAPACITOR 1009 M 0 BY PASS CONDENSER 1010 MO CHOKE 1021 PA TANK INDUCTANCE 1022 PA TANK CAPACITOR 1023 A...

Page 28: ...M 0 CHAIN CAPACITOR 2616 NEUTRALIZING CAPACITOR 2617 MO GRID PARASITIC RESISTOR 2618 P A GRID BLOCKING CAPACITOR 2619 MO TANK COMPENSATING GAP 2620 MO TANK COMPENSATING CAP 2621 P A TANK INDUCTANCE 2622 PA BAND CHANGE SWITCH 2623 PA FIXED TANK CAPACITOR 2624 PA FIXED TANK CAPACITOR 2625 PA FIXED TANK CAPACITOR 2627 ANT COUPLING COIL 2628 ANT COUPLING SWITCH CONNECTOR DESCRIPTION M UNIT PIECE OF AP...

Page 29: ...Weight of Case CS 48 4 375 lb Fig 12 Case CS 48 Dimensions and Weights 0 NAME PLATE 0 0 O A f 311 t13 4 0 ...

Page 30: ...RUBBER INSULATION K 7972345 W V I Ir 1 38 IA UNIT PIECE OF APPARATUS S V 41759I 2 MARC RUBBER INSULATION RED II 7571345 PT II T 8 1450158 R K 7975873 NOTE CUT ALL LEADS TO PROPER LENGTH SUCH THAT THEY TAKE THE POSITIONS SHOWN IN CONNECTION DIAGRAM WHEN TERMINAL BOARD IS SECURED IN PLACE TO PREVENT EXTERNAL BRAID OF B CONNECTIONS FROM FRAYING ASSEMBLE CAP K 78 76 3 91 TO RELAY END OF EACH LEAD BEFO...

Page 31: ... 412 2i MOUNTING FT 107 4 PI SI TRANS 4101 I I NAME 0 a PL 59 ALLOW 4 TO REMOVE PLUGS H TO OPERATE SNAP SLIDES 3 f iSiV T1 TO O SNAP SLIDES 0 I Weight of Dynamotor Unit PE 73 C Less Mounting 37 25 lb Weight of Mounting FT 107 1 45 lb Fig 14 Dynamotor Unit PE 73 C Dimensions and Weights ...

Page 32: ...ANS A GND TOP 1502 A ROTOR 014061 REAR VIEW CONNECTION SIZE OF CONDUCTOR UNMARKED 10e DIA COPPER WIRE TINNED A 080 DIA COPPERWIRE TINNED AT POINTS MARKED X USE COTTER PIN it x I Fig 15 Antenna Tuning Unit BC 306 A Connection Diagram ...

Page 33: ...ND 6 4 MOUNTING HOLES FORKS FL HD SCREWS MOUNTING FT 142 9 Weight of Antenna Tuning Unit BC 306 A Less Mounting 9 062 lb Weight of Mounting FT 142 0 687 lb Fig 16 Antenna Tuning Unit BC 306 A Dimensions and Weights ...

Page 34: ... 257 DIA HOLE 2 MOUNTING HOLES FOR 10 SCREWS Weight of Mounting FT 115 B 0 195 lb ip 52 16 I 16 16 2 1 II Fig 17 Mounting FT 115 B Dimensions and Weight ...