Gates Radio Company BC-250GY-1 Instruction Book Download Page 1 | Manualshive

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Summary of Contents for BC-250GY-1

Page 1: ...a INSTRUCTION BOOK FOR GATES MODEL BC 250GY 1 TRANSMITTER I B 888 0836 001 Gates Radio Company Quincy Illinois ...

Page 2: ...check of the wind ings may indicate that the transformer is defective whereas in reality this is a normal reading and the modulation transformer is performing normally In order to properly check this transformer outside of the transmitter circuit merely apply 117 volts 60 cycle a c to the secondary winding Check the voltage on each half of the primary winding If the transformer is oper ating norma...

Page 3: ...eneral Operational Procedure 8 Tuning Procedure 10 Making Performance Measurements e 13 SECTION IV TYPICAL VOLTAGE AND CURRENT CONDITIONS OF BC 250GY 1 16 Conclusion 16 Warranty 17 PARTS LIST 1 3 ADDITIONAL INSTRUCTION BOOK M 5422 Oscillator Unit Helpful General Information A E PHOTOGRAPHS DRAWINGS 810 4339 001 Detail Control Circuit 813 9110 001 Frequency Load Determined Components 813 9191 001 T...

Page 4: ...KC as ordered 30 300 ohms as ordered 5 cycles 3 or less at 95 modulation 3 or less 50 7500 cycles 90 modulation 1 1 2 DB 30 10 000 cycles 2 DB 30 12 000 cycles At least 55 DB below 100 modulation 500 600 ohms 8 DB 2 DB for 100 modulation 230 Volts 2 wire 50 60 cycles 1 6 KW at 95 modulation high 34 wide 33 deep 78 900 pounds packed 112 cubic feet Oscillator 12BY7A 1st IPA 12BY7A 2nd IPA 813 Power ...

Page 5: ...lated frequency determining components could be in error making resonance and or loading of one or more circuits not complete In such cases advise the factory immediately The radio frequency output can be load from 30 to 300 ohms but can components It is also essential that load impedance be specified If this load impedance active such as with a direct fed tower will be required The radio transmit...

Page 6: ...ers approximately 150 volts to the M 5422 oscillator unit and with this voltage the unit delivers ample power to drive the following 813 stage The 813 stage is equipped with a grid current meter M8 mounted on the 813 chassis The M 5422 oscillator unit which is oper ating when the filaments are on can be tuned according to in structions for the maximum grid current reading on the meter M8 This will...

Page 7: ...y to tune should be used except to a point of extremely low capacity which will tend to result in arcing in the condenser In case of changing frequency to a new frequency from that pre viously supplied when manufactured the following information will be valuable The tuning ranges will be as follows For 1200 KC to 1600 KC use 15 turns on each side of center tap first tap from center tap The second ...

Page 8: ...chassis servicing of the audio deck it is only neces sary to remove the knurled thumb screws and this chassis hinges back revealing all under chassis wiring and components for fast servicing where required It should be noted that the oscillator bias power supply is so constructed that 60 volts is taken from the negative side of this supply to provide bias voltage for the modulators which is indivi...

Page 9: ...gram In the case of the mod ulators the resistors also load the inductance of the coil pre venting distortion through this element 8008 Rectifier Tubes The 8008 mercury vapor rectifier tubes are sensitive to temper ature If the temperature is too high or too low this type of tube has a tendency to arc back or conduct current in the re verse direction resulting in a high voltage short circuit When ...

Page 10: ...on a 208 volt power source without modification but is designed to operate either on 50 cycles or 60 cycles The audio input line connects to the terminal board at the bottom rear of the modulator panel right side facing from rear This should be a shielded pair The transmitter input is 500 600 ohms working equally well with either ohmage Other input impedances may be had by changing primary taps on...

Page 11: ... there to the system ground Connecting the Load The coaxial or open wire transmission line or the direct coupled antenna connects to the feedthru insulators on the top of the transmitter In the case of coaxial transmission line or open wire transmission line the ground portion of the transmission line should be firmly secured to the top of the cabinet also so that the ground path will not have to ...

Page 12: ...ded and that the ground to the transmitter is tied to the main ground of the antenna system THIS IS VERY IMPORTANT AT LEAST 2 COPPER STRAP RECOMMENDED 9 Making certain that transformers with voltage correction taps have one side of the supply line connecting to terminal 1 10 Making sure audio wiring has been properly shielded and that the shields have been properly grounded and that no input wire ...

Page 13: ...MENT light will light With the back door closed pressing the high voltage ON switch S2 should cause the plate contactor E4 to close Pressing the high voltage OFF switch should cause this contactor to open With the contactor closed in the high voltage ON condition opening the back door should cause the contactor to open Opening the door and blocking or holding the door interlock switch S4 the high ...

Page 14: ...ately half the value for the particular transmitter load given in the tabulation of TYPICAL VOLTAGE CONDITIONS included in this instruction book The power amplifier shows no tendencies for parasitic or self oscillations so no concern need be felt on applying plate vol tage without the stage being completely neutralized Neutralizing may be quickly and effectively done by tuning the plate condenser ...

Page 15: ... provided the line current meter Ml is usually 0 3 amperes while for a 250 ohm transmission line meter Ml is usually 0 2 amperes The formula of I2R is usually employed in computing the proper line current where the line impedance is known and of course is likewise employed whrlre the antenna resistance is known in the case of direct coupling A dummy antenna of known value is usually pre ferable in...

Page 16: ...n complete resonance will eventually produce the desired results where the load is not below 30 ohms or exceeds 300 ohms Final current into the line load on the formula I2R is of course the answer to the correctness of the load The efficiency of the BC 250GY transmitter is 70 and seldom over 75 It should be remembered that efficiency is measured into a known load and preferably a resistive load de...

Page 17: ...ts or stray pickup introduces effects in the receiver which do not indicate the exact performance obtained The use of the SA 131 kit is fully explained in the instruction book for the set The Gates M 5693 Modulation Monitor has provisions for making performance measurements other monitors may or may not have this provision Before accepting adverse readings when using a modu lation monitor as the d...

Page 18: ...f the transformer and connecting whichever way gives the best results for all frequencies The modulator grid connections could be interchanged and doing this requires that the feedback also be reversed Both reversals that is the driver and modulator could be tried simultaneously In each case the modulator bias should be adjusted for 50 cycle distortion below 3 if obtain able Some noise improvement...

Page 19: ... connections may be made again Should any deviation occur radically outside specifications this may be due to damage to components or tubes during shipping or to a mis interpretation of connection instructions If after a period of operation the performance is outside specifications this may be due to tubes or to some component aE ing such as a resistor changing value 9 11 63 5 BC 250G 1 ...

Page 20: ...ad 50 ohm load 330 V 230 V 110 MA 14 V 6 3 V A C 1400 V 50 60 MA 32 36 10 V A C 145 160 V 6 3 V A C 1400 V 350 400 V 120 160 MA 1250 1350 V 246 MA typical only will vary 10 V A C 70 120 MA 1 amp 1 84 amp 2 24 amp Conclusion A radio broadcast transmitter regardless of its size cannot be fully described in an instruction book such as this as to every possible condition that may arise in the process ...

Page 21: ...d of failures a blank on a log book Also remember that cleanliness in the maintenance of the broad casting equipment will pay big dividends Take a period each week for cleaning the inside and outside of the transmitter and access ory equipment for testing tubes making sure all connections remain solid and the many other things that are entitled good maintenance In so doing happy and satisfactory p...

Page 22: ... 0080 000 576 0001 000 F1 F2 398 0231 000 F5 398 0019 000 J1 612 0230 000 J2 612 0231 000 9 11 63 1 Cap 10 mfd 2000 W V Cap 1 mfd 1500 W V Cap 40 mfd 150 V Cap 5 mfd 600 W V Cap 20 mfd 450 V Cap 2 uf 200 V Cap 4 mfd 600 W V Term insulated Cap 005 mfd 1200 W V Cap 002 mfd 600 W V Cap 500 mmfd Var Cap 0015 mfd 2500 W V Cap 2500 W V Det by Freq Neutralizing Condenser 6 12 pf Cap 02 mfd 600 W V Cap 00...

Page 23: ...ter 0 1 MADC movement w 0 2500 V DC Scale M7 630 0115 000 Fil Voltage Meter 0 15 V AC M8 632 0525 000 813 Grid Current Meter 0 25 MADC P2 612 0099 000 Plug P3 610 0231 000 Connector Male for J1 P4 610 0233 000 Connector Male for J2 R1 552 0391 000 Potentiometer 1000 ohms 100W R2 542 0209 000 Res 200 ohms 50W W W R3 914 3421 001 Meter Multiplier 2 5 megohn R4 R5 552 0321 000 Potentiometer 1500 obis...

Page 24: ...ransformer T5 472 0199 000 Filament Transformer T6 472 0171 000 Filament Plate Transformer T8 472 0142 000 Input Transformer T9 478 0038 000 Driver Transformer TB1 614 0241 000 Terminal Board 20 term TB3 TB8 614 0111 000 Terminal Board 3 term TB4 TB11 614 0092 000 Terminal Board 2 term TB5 614 0241 000 Terminal Board 20 term TB6 614 0100 000 Terminal Board 10 term TB6A 614 0118 000 Terminal Board ...

Page 25: ...ty C9 or more turns of the slug in L3 may be required for resonance Shorter lengths of monitor cable on frequencies from 600 Kc to 540 Kc may prevent the unit from tuning to resonance If this is the case capacity should be added across the cable to make up the difference in effective capacity Longer lengths of cable would mean less capa city or less inductance needed for resonance in this frequenc...

Page 26: ...ble to tune crystals from 540 Kc to 800 Kc to their 2nd harmonic After resonance has been obtained the crystal may be set to exact frequency by using the frequency monitor Set the slots of the trimmer condensers located on the front of the unit at right angles to the plane of the trimmer mounting screws With the crystal selector switch turned to 1 crystal the frequency should be very close to zero...

Page 27: ... 000 Receptacle L1 L2 494 0033 000 R F Choke 2 5 mh L3 492 0019 000 Variable Coil 105 200 uh R1 R6 540 0764 000 Res 100K ohm 2 W 10 R2 540 0740 000 Res 1000 ohm 2 W 10 R3 R9 R10 R11 540 0757 000 Res 27K ohm 2 W 10 R4 540 0754 000 Res 15K ohm 2 W 10 RS R8 540 0752 000 Res 10K ohm 2 W 10 R7 540 0730 000 ates 150 ohm 2 W 10 R14 540 0284 000 Res 10 ohm 1 W 5 S1 913 0316 001 Rotary Switch V1 V2 370 012...

Page 28: ...rn U ST C7 U ...

Page 29: ...u ó g 3 o J _N 5 N In o Y3 áO 3 D Q r CO N ro to Y 3 O Y 3 O N 1 N N 2 o n 171 oÓ E f LL X fl I LI LL X 1 1 V N n a u f CO r N 0 n 8 o la E9 EPE 0b6b N73 E 23 LI II HQS bL9L N 3 l 4 BS Z L 9617 L NO3 9Sii 9 rl zdL i3 ...

Page 30: ... the higher the efficiency the better 3 COMPUTING POWER OUTPUT Power output is computed either into the radiating antenna or a known dummy antenna In either case the resistance measurements are known Your consulting engineer will measure your antenna tower and give you the resistance measurement In most Gates built AM trans mitters an inbuilt dummy antenna is provided having a resistance measureme...

Page 31: ... stage to the final audio stage Other outage conditions not affecting the transmitter are listed below for your checking Under certain conditions especially at higher altitudes the guy insulators will arc usually caused by static conditions This will nearly always cause an outage as it changes the antenna characteristics This is hard to find as it is hard to see Use of field glasses at night is th...

Page 32: ...r and stockholders When trouble comes he is under pressure He will do his best to correct the problem as fast as he can It is well to remember that electronic equipment has many circuits and many avenues of travel Where problems are known the solution is usually quick Where the problem must be found the solution will take time It is well to remember that if equipment did not need maintenance it wo...

Page 33: ...800 0553 001 ...

Page 34: ...800 0627 001 ...

Page 35: ...800 0627 003 ...

Page 36: ...800 0627 002 ...

Page 37: ...800 0553 005 ...

Page 38: ... r I 3 Z O 01 1 n LL ó r 9 Lr 41 r o co o r qR7 a w J Z o a 1 Li1 U O 0 d OS ti 6 L9SS ND3 3 5Z 6 1921 OLISp N33 OM N 8 d sA msn ar csN OS N7 ...

Page 39: ...620 0004 1 ir Iv y 600 00 07 005 006 007 55o 0009 006 007 01 LINE CURRENT METER Ml 0 1 5A 10 3A 0 3A 813 810 COUPLING CONDENSER C27 1600 750 KC 0001 Type H 2500 WV 750 550 KC 0005 Type H 2500 WV NOTE Higher capacities may be obtained by parallel connection of two condensers Alternate Adjustment 0001 mfd at C27 and increase 813 grid tap on L7 Use whichever gives satisfrIctory F A drive with lowest ...

Page 40: ... D C Osc plate Filament Transformer T6 5 10 5 V 10 A O 7 8 9 10 5 V 10 A 10 3 11 12 6 3 V 2 5 G 4 PA Mod Filament Transformer T4 P B P RF G Modulation Transformmr 10 T3 Connect To Join to 4 to 4 t 3 to 5 Audio Ind ut Transformer T8 3 7 6 2 5 1 O 4 500 ohm 1 6 3 200 ohm 2 5 3 50 ohm 2 4 2 4 Driver Transformer T9 1 C PRI 230 V 50 60 2 3 4 5 1 V L 15 A Rectifier Filament Transformer T2 TRANSFOREER CC...

Page 41: ...t 4 3S 8 3c T13S a0 55 11 IC rSae 6C ro9 INC OG P GOP 4o9F IUC 1 157 75 80 INC Tt3 13 TOBA 71A 1 INc T13 9 31 83 INC 7B10 84 91 INC BIS eF De1i0a MOO MO PIGCUP RUD10 P iNCL 500 PPN40 FÚ010 CH ASSIS OVE C o FlI RELAYS RUOO PFPIEL Ailcl Ci In SIS FEEOBP CIC OSCILLATOR 8008 _ GATESUIÑADIO COMPANY vj q C 01157 70 POINT LoIZI150 Bc 250 GY kfl á ry MO 3 1GOC DR Bc f e DATE 9 5 63 DR NO Uv W CH BY K ENG ...

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