Gates BC- 250T Instructions For Installing And Operating Download Page 2

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Summary of Contents for BC- 250T

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Page 2: ...INSTACTIONS FOR INSTALLING AND OPERATING THE GATES MODEL BC 250T 250 W TRASMITTER 113 875 Gates Radio Company tlincy Illinois...

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Page 4: ...REMOTE CONTROL ACCESSORIES BC IT BC 500T BC 250T...

Page 5: ...tion of the arm same view resistance will decrease riti application of idecrease voltage the resistance will increase 2he existing plate voltage meters in the BC 1T BC 500T and BC 250T Transmitters re...

Page 6: ...their shunt resistors directly across their respective coils 4 The G terminal of the two terminal strip on kit M 4720 connects to a good ground point within the transmitter Run a lead from the other t...

Page 7: ...different manner so that indivi dual filament control for the various transmitters is possible Each transmitter employs its individual slave relay associated with its respective transmitter filament c...

Page 8: ...Summary 19 Guarantee 1 2 Photographs Electrical Parts List 1 5 Drawings A 30957 Tuning Chart BC 250T A 30958 Typical Voltage Chart A 30584 Typical Curves Vacuum Ovenless Crystals A 30585 aood Base B 1...

Page 9: ...ulation 11 Noise Minus 60 DB below 100 modulatian 12 Carrier Shift 3 or less 0 100 modulation 13 Output Impedance To match 50 70 ohms at all frequencies 540 1600 Kc Coupling unit available for other i...

Page 10: ...ainted preferably black This base should be lagged to the floor and measures taken to insure that the top side of the frame is perfectly level This will give a good solid level base on which the trans...

Page 11: ...lded steel cabinet with most of the low power RF and audio components mounted vertically on a formed aluminum panel and shelf assembly The high power modu lators and power amplifier 810 s are located...

Page 12: ...h is in the position marked Plt Our Osc Bufl The positive plate potential applied to the oscillator unit is derived from the 600 volt power supply through a 20 000 ohm dropping resistor R9 Printed wir...

Page 13: ...A assembly is lade up of PA tank coil L12 PA tank condensers Cil and 012 always operating in parallel outpuL coils L13 and L14 loading condensers C13 and C14 modulation pick up coil L15 plate blockin...

Page 14: ...ing a 230 volt AC circuit through the coil of master overload relay K3 K3 energizes and its contacts open causing the holding circuit of the plate contactor K2 to open and drop out the plate relay Thi...

Page 15: ...ass JP modulation is used in the BC 250T a pair of 810 tubes providing the means The modulation transformer 3 working with these tubes is located in the base of the cabinet on the right hand side towa...

Page 16: ...s Fl and F2 are located at the left bottom section of the inside panel asseilbly directly over TB 1 This fuse receptacle is the terminal location for the two 230 volt primary input wires Fifteen amper...

Page 17: ...potentiometers R1 and R2 indirectly vary the modulator bias by controlling the cathode follower bias and thus the current flow through the cathode follower resistors Rh l and R12 There is ap plied a...

Page 18: ...relays have been held firm by use of paper and tape Tube caps and parasitic suppressors have been taped down to prevent damage by vibration during shipment Certain components have been supported by wo...

Page 19: ...the trans mitter The AC primary wires were brought in through this opening also This internal ground follows up the cabinet support and fin ally connects to the aluminum PA tuning assembly at the top...

Page 20: ...rminal connections etc 6 Give all soldered connections a brief lookinc over The equipment has passed several rigid inspections during its course of manufacture but something may have been over looked...

Page 21: ...proximately 100 to 140 grid ma flowing depending again on frequency tuning loading etc At this point set the multimeter selector switch to Input Audio Cath The multimeter should indicate from 5 to 10...

Page 22: ...er 4 Adjust the P A tank coil L12 tuning by means of the right hand knob on the P A panel Marked PA Tune when resonance is reached the grid cur rent as indicated on the multimeter will dip noticeably...

Page 23: ...s in formation Place a tube connector on one 8008 rectifier tube This procedure will allow a partial supply of voltage from the high volt age rectifier system Place in position the front screen which...

Page 24: ...possible to balance the modulators easily while the transmitter is on the air on program During a slight lull in programming the modulator cathode meter 114 will drop back and at this time the modula...

Page 25: ...stal has been so adjusted it would be well to adjust the station s frequency monitor to coincide with the trans mitter The frequency monitor should have been heating a sufficient length of time to sta...

Page 26: ...available use a very fine grade of sandpaper sparingly Printed wiring is used in four sections of the Gates BC 250T trans mitter A Oscillator Unit M 5422 B Portion of the RF Driver Stage M 5566 C Inpu...

Page 27: ...as done everything possible to provide the finest equipment available today It is not possible to supply the operating location the ac tual ground system and in some instances the associated equipment...

Page 28: ...warranty These warranty periods com mence from the date of invoice and continue in effect as to all notices alleging a defect covered by this warranty received by Gates Radio Company prior to the exp...

Page 29: ...Radio Company under a warranty will be f o b Quincy Illinois or f o b the applicable Gates Radio Company shipping point 7 Gates Radio Company is not responsible for the lose of or damage to equipment...

Page 30: ...imme BC ITI BC500T BC250T A M TRANSMITTERS...

Page 31: ...PA LOAD PA TUNE LI4 LI2 C 0 MI M2 M3 M4 M5 S5 S6 TI VI V2 V3 V4 S3 S4 LI FRONT VIEW BC250T 250 W A M TRANS M 5627 DL 141...

Page 32: ...CIO V7 LIO LII R2 RI SI S2 RI4 07 02 SI RI3 CONTROL PANEL BC250T 250 W A M TRANS M 5627 DL 143...

Page 33: ...log WOW em amb maababow ab WINO f lam b Mine 1 time boaarau ea Ire ma lobo Mr mew l Im I g Malmo ea l...

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Page 35: ...T7 XV5 C6 05 XF4 BACK VIEW PANEL Ei SHELF ASSEMBLY BC IT BC500T BC250T A M TRANSMITTERS...

Page 36: ...DL1 33...

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Page 38: ...L2 LI T1 14 12 12 13 V3 V4 15 L4 L3 C4 R11 C2 S3 S4 BASE COMPONENTS FRONT VIEW BC250T 250 W A M TRANS 1 415627 DL I47...

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Page 40: ...S7 sa R26 M5 R8 R7 S6 S5 R20 RI9 RI4 CONTROLS Fl L 8 PLATE START STOP 8 ADJUST BC IT BC500T BC250T A M TRANSMITTERS...

Page 41: ...Y rh e I 02 rIttil SI Y CI 2 OSCILLATOR UNIT M5422...

Page 42: ...3 meg 3KV Precision Meter Multiplier Control Fil Rheostat 15 ohm 150 W Control Plate Rheostat 400 ohm 300 W S3 S4 Interlock Switch See Drawing B 65300 101 Ti AP 7235E Transformer High Voltage Power T...

Page 43: ...V3 XV4 Socket R F DRIVER PRIN2ED CIRCUIT ASSEMBLY Cl C2 C3 C4 C5 C6 C7 Cap 01 mfd 1000V W Li Choke 2 5 mh L2 L3 A 30520 101 Parasitic Suppressor R1 Resistor 12K ohm 2W 10 R2 Resistor 250 ohm 20W R3 R4...

Page 44: ...0 500 MA DC Meter r A Voltmeter 0 1 MADC w 0 3000 V Scale Meter Modulation 0 500 MADC Multimeter 0 1 MA D C w 0 30 0 300 IA J C Scale A 10534 101 C 77705 101 I ANEL Multimeter Series Resistor Ass y F...

Page 45: ...1W 5 Si A 10900 2 Mod Switch 52 Multi Meter Switch T6 AI 3002 Transformer Audio Input T7 AP 30098K Transformer Bias T8 AF 30100K Transformer Multi Fil 6 3 V Tg AP 30257E Transformer Multi Fil 10V TB1...

Page 46: ...d 500 V W Cap 800 mmfd 500V W Cap 01 mfd 600V Cap 100 mmfd 500 V W Variable Cap 6 7 140 mmfd Cap 100 mmfd 500 V W Receptacle R F Choke 2 5 mh Variable Coil 105 200 mh Resistor Resistor Resistor Resist...

Page 47: ...N i N OU 1 e N e _Ti VI 1 1 p o 0 CQ C 1 1 C OIL L12 I I I II 0 0 o IND MICROHY r q 0 0 Ti et _n Ji 7 n Ln 0 O 0 00 0 0 i s 5 P rt D 1 X1 F 0 I F O 121 F N F 1 N H F P COIL L13 rn CY VI 0 0 0 TURNS A...

Page 48: ...ox 50 60 volts Neg Filament Volts 10 A C Crystal Oscillator V1 12BY7A Plate Volts 100 D C Screen Volts 50 D C Cathode Volts 8 D C Filament Volts 6 3 A C First IPA V2 12BY7A A part of Ose Plate Volts 2...

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Page 50: ...5 11111 II 0 22 4 1 I 1 26 Y 1 Y 4 15i j0 10 b 4 6 4 I I 45 1 A 4 t Jr I r 1 1 DRILL CTRSORE I T TO CLEAR v2 Li FOUNDA TION BOLT ir l BOLT HOLE DETAIL Cm BY ent DATE 404e hiTL ZX 41 YEL PINE TITLE WOO...

Page 51: ...IZEQUeNCY B 138 6 5 01 ies y L3 Rit Z7K Zw RIO vvvvsn 27K 2W Rq 27K 2W s 1 100 R5 Re3 OK 2W 10K C8 01 2V RI3 METER 8 17 6 RI1 iw FIL FIL X RI2 4 l000_n_ 2w 3 2 1 METER CIO 100 C9 140 JI 1 P 308 DeSOLD...

Page 52: ...01 R a50 n_ 7 C S 0 I 47_n RIO 5K L7 1 4 c l CI7 001 C15 1_ c7 1 00025 L _ pRirqraD WIRING TO GRIDS v o VT CZ V d 11 1500W cicz 01 TO CIO NEUT C ONb To Two E000_n_ PARALLEL CaRID RESI STORS R7 8 RS C...

Page 53: ...82 K IL C3 47 6 e 5 G XV2 GBGG G a o o R5 ZO LI 1 000 C V 3 GBGGG C5 T 0 R23 47_11 co C7 33 C4 R3 1000 A o a 22 4 s 07 20 013 II o Il l e 5 csJ r 0 u a _ 0 N 0 F y r RI7 1G T C XV4 0 13G6G Y R18 47 11...

Page 54: ...N Oa PLATE PILOT TIII 7 3 K 3 ilesree K4 181 11 c 2 15n TIME OEM 5 Vocr Dooe ea blocr 7 TB I S4 ife de Foe K5 x4 Teri sv4 1 TIME DeL A7 HEP TEE Foe A 5 r D 2 3 14 OCO Q_Oz in 1 M PLL f _ 8105 Te f a P...

Page 55: ...28 DOOR SWING 29 31 32 TOP VIEW 8 r 7 ss1 Lffl M Sil CB CVO FRONT VIEW A L34 13 264 13 21 16 7 26 32 SECTION A A On 31 13 32 26 i r 2 13 3 29 32 SIDE VIEW A...

Page 56: ...103 102 101 LIST OF PARTS OTT OTY OTY OTY ITEM REFERENCE ON FIN FIN DESCRIPTION MATERIAL TO AUD II 280 V TO AUD I0 TO AUD 9 v3 v4 TITLE 19 A S _ SUPPLY sch e T Inc 1KW xiirg BC 17 15373 co kV X 17g B...

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Page 58: ...X v se dd 4 e 3 CLE o ir 44 1 7 4 7 S arr 1 1 3 7P1 2 TPI I v vr De v E e 115547 C 270 9 4 l e xe v 4 e Rd 82 K C3 4211 44 Baca 4 e k 4 RS 4 2o ca ri L e i nl 47d X 3 68oca 1 1 4 r e t 21 17 0001 3 2...

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Page 60: ...L RIS z t r J elm Mi 7P1 5 E Ii ea Rs I R7 I 2 2 al I TV 15 T3 mereel t 4 4 7 a L3 eso e RI ICL Pez PO tO itmr CIOL OLT STOP CONTACTS SI RI com n 7 0 2 761 14 33 Pet efseeessic a T9 re fieseog s v p...

Page 61: ...x sz Tel 13 xi 55 1 t 2 0 0 0 3 7 mt fE ne7i 44 1 14 egg genes 4gegoned T131 2 44 Zi Te 4 T111 6 54 01 41 0 4 44 g IglgOlgosig ei3 15 pee rim rrm _1_ Tees XF1 COMPRO 5A 0 dk laZ TIII IC 5A 2bov WITH S...

Page 62: ...olic board Put the iron tip on the fillet under the chassis right be side the component lead being removed Put a gentle but firm pressure on all leads and components being moved while the heat is appl...

Page 63: ...y the iron and push against the socket to raise it at this point Use the thumb and fingers only to raise socket to prevent damage to the board The socket will not move very much but any move ment at a...

Page 64: ...y unless it is tuned up incorrectly If you have low efficiency your first check should be into an approved dummy antenna Light bulbs or dummy antennas of unknown resistance under power do not help As...

Page 65: ...rs Enough will cause arc overs that will blow fuses Look for cable abrasions 15 It is also important to note that if you have had a fuse blowing ordeal that after locating the cause the fuse clips may...

Page 66: ...d voltage varies at input under modulation Often hard to find as public utility meters and graphs are slow speed Best check is to apply sine wave to transmitter Check line voltage at zero modulation a...

Page 67: ...ir out of closed transmitter buildings Check tubes at least monthly Poor tubes mean poor quality and eventual outage Rotate the bigger tubes every month Include spares in this rotation both to prevent...

Page 68: ...e phenolic board Put the iron tip on the fillet under the chassis right be side the component lead being removed Put a gentle but firm pressure on all leads and components being moved while the heat i...

Page 69: ...old iron tip on one of the folded leads as soon as the solder melts push gently but firmly on the side that will lift this lead The capacitor should be pushed over just far enough to clear the lead fr...

Page 70: ...e size just remove the solder It is soft and easily removed in this way L fold clip here EJ A B Fold the leads on the new part to the same spacing as the mounting holes Insert the part and fold the le...

Page 71: ...ly the iron and push against the socket to raise it at this point Use the thumb and fingers only to raise socket to prevent damage to the board The socket will not move very much but any move ment at...

Page 72: ...s it helps in many instances to find trouble 20 Give your opinion as to the cause or fault of your problem Use another sheet of paper if need be 21 Have you experienced any arcing If so state where _...

Page 73: ...ILLINOIS U S A Subsidiary of Harris Intertype Corporation SERVICE QUESTIONNAIRE If you have a transmitter problem your filling out answers to the following questions will permit our various engi 3 to...

Page 74: ...GATES...

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