RCA-Victor-Co-Inc-84BT 电路原理图.pdf

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1、MODELSPA -B 84BT8-133f Four -Tube, Single -Band, Battery Operated, Superheterodyne Receivers SECROJ. LG - 400 AC. SEC RDJ. Le 400 KC. 5N-715 Radiotron and Trimmer Locations (Model 84BT) ANT C3 MOOKC SEC ROJ LB 400 KC. OSC MOOKC. SN-710 -Radiotron and Trimmer Locations (Model 84BT6) Model 84BT or 84B

2、T6 MODELeitBT Conversion to 1-1/2 v.operation. Refer to page 824B. Electrical Specifications Frequency Range930-1,720 kc Alignment Frequency1,500 kc(osc., ant.) Intermediate Frequency RADIOTRON COMPLEMENT (Nloom. 84BT) (1) RCA -1C6FirstDetector-Oscillator (2) RCA -1A4.Intermediate Amplifier (3) RCA

3、-1F6Second Det., A -F Amp., and A.V.C. (4) RCA -1F4Power Output Pilot Lamp84BT, (1) Mazda 2.0 BATTERIES REQUIRED 460 kc ( MODEL 84BT6) ( 1) RCA -6A7FirstDetector-Oscillator (2) RCA -6D6 Intermediate Amplifier (3) RCA -75Second Det., AF Amp., and A.V.C. (4) RCA -42 Power Output volts, .06 amp.; 84BT6

4、, (1) Mazda No. 40, 6.3 volts, 0.15 amp. 84BT .A, one plug-in,2V2 -volt Air Cell,or one 2 -volt storage battery; B, three 45 -volt, heavy-duty, plug-in type B batteries; C, one 41/2 -volt C battery tapped at11/2 volts. 84BT6A, one 6 -volt storage battery; B, none required; C, three bias cells (Stock

5、 No. 12681). CURRENT CONSUMPTION MODEL 84BT MODEL 84BT6 A at2volts0.42 ampere. A at6 volts 2.95amperes B at 135 volts 25 ma(Suppliedfromvibrator) Fuse Rating1/2amp. 5amps. POWER OUTPUT Undistorted. 0.3watt Maximum0.5watt LOUDSPEAKER Type: permanent -magnet dynamicDiameter: 6 inches Voice coil impeda

6、nce: 21/4 ohms at 400 cycles. Bias Cells (Model 84BT6 only).-The bias cells are used only for the purpose of supplying bias potential and should never be measured with an ordinary voltmeter or other device which draws any current. A simple check on the cells may be made by connecting a milliammeter

7、inthe plate circuit of the tubes biased by these cells(6A7 or 6D6, 2 cells;75,1cell). Measure the plate current with the cells in the circuit, then carefully remove the cells and substitute a voltage equivalent to the rated cell voltage.If the first read ing obtained (with bias cells)is more than 40

8、% from the latter reading (with known voltage), the bias cells should 0.5 watt 0.8 watt be replaced.This 40% difference is equivalent to a change of approximately 25% battery voltage. Precautionary Lead Dress (Model 84BT6 only).-(1) Green lead from antenna coil to antenna section of tuning condenser

9、 should be dressed asfar as possible from tube No.1(6A7).(2)Dress brown and green twisted leads (vibrator transformer T2 to vibrator socket) under capacitor C21. (3) Dress brown -black lead (T2 to C25) away from red lead which connects terminal in vibrator compartment to SG of tube No. 4 (42).(4) Ke

10、ep all other leads in vibrator compartment as close to chassis base as possible. RCA VICTOR DIVISION OF RADIO CORPORATION OF AMERICA, CAMDEN N. J., U. S. A. 收音机爱 好者资料库 RadioFans.CN PAGE 316-B 84BT 8. 84 BT6 CZ I 4.4 55 MMF LlL2 362 cop52 ,- ; 0. Clz-zommF 1 MED. _L EXTGND. CHASSIS 3 0 1.11, L,3 C4 2

11、5-310 MMF. 1TDET4 C6-2-20JMFC5-1zommr. OSC.-ICB-r11I La-Iln L4 LS - 5.72 33C0F/40D. 7.221 O -C7 MFD 45V 45 4 Fl 1/2.AMP 2V STORAGE BATTERY FUSE. ADD 0.66 OHM RESISTOR IN SERIES WITH POSITIVE (+IA - WHEN USED WITH 292 VOLT AIR -CELL BATTERY NOT USED WITH 2 voLT sToRAGE BATTERY. sa rWI SI Ra. 22,0002:

12、 CIO 0.25 MFD C9 MMF I.F. IA41.7-1-lir ArL8-1. 2 2 ZI mL ri CI a Ir T.:a. ,zco ii R3 ,i mmr. 22100 R4 20.0)20 EMIR C13 180 MME R7 2E0 C14 -.Do25 R5- 2.2MEG. 2DET., A V. C. 4,A.F.- IFS 14 1 MEG OUTPUT I F4 C0C17 .007 MFD 0 CIS0 IMF /C19 4 MFD VOL. CONTROL R6 10 MEG 5 DIAL LAMP .1. 64951 0 Le CI 0.1MF

13、-CLIEr 33 L.5L4 52 DIAL LIGHT -Schematic Circuit Diagram (Model 848T) 1.70E7. 05C. 6R7 GD6 TO HEATERS 0.652 AMP LID L.1 PI DC1= WATT. iSl 6Le. BATT5W 0.25 P 2111-1). 3 / teo T.22,z. C9MM. 56 MN* L5 L6I111 L7 LB V BRAT OR 10412. RI I 6 80.2 22 MP C23 .0IMPO. RI2 6B02. .0J25 MFD 144 250,0,10 TIL VOLUM

14、E CONTROL O Vr. TI 4,- C18 0035 MFD -4 5V CBATTERY R3C14 -dlOTL7r14 144vELLow r SHIELD V!RUE RECORD PLAYERPLAYER CONNECTIONS D5T.,RVC.A F001 N1Fr,.OUTPUT 75 C17 42 RIO PS 270000 470 DP,A R2 22 0002 2902 L15 0 QS IC25C26C27 ,Act/ C24 0MFD.13MED. I 7T -Schematic Circuit Diagram (Model 848TO) CAB 00r M

15、FD. P-84052-0 4CI4 -dt,REEN YELLOW RECORD PLAYER CONNECTIONS. NOTE: On later production Model 84BT6, an RCA -41 output tube is used in place of the RCA -42. All circuit and speci- fication data remain the same except the A current consumption at 6 volts which is 2.65amperes. 收音机爱 好者资料库 RadioFans.CN

16、PROIKYE PAGE 317-B 84BT 41URE. 1C-:-? 125V-6V. - - CATHODE CURRENT HAS VAT. NA1 . .151B5. MS RM. C.G. 2.06T,A.V.C., I. F. -50V. -75 606 OUTPUT 5, A. F 42 V)-1 ;4N ilgire2.1.F TRANS r* 51601 V.(04 (31V.(82 155V., *- 1673V. 163y. e;fete el 7 0 V. ; BOTTOM VIEW -REAR OF CHASSIS MODELS4STS P-84075 135V.

17、407(50V (-4.5 .211. -0.1V. 129Y.II e PLATE CURRENT NAl ETD. NAL OF411,11. NAL53 MS. HAS N4 10.01.1,115. I It1 66V. 2V.135V.:(-3V.t 0.911.91+,11_, 01111 ;4(49.eL rR i 1TDOSC.Is* I.TRANS. IC6 C.G (-0.9V.*) r- t 2VtiL135-V.: I. F 4 I A4 OUTPUT2. DET,A.V. 1F4- 1F6e.G. -I.5v 20V. V., , 2V., tr BOTTOM VIE

18、W- REAR OF CHASSIS MODEL 1146T -Radiotron Socket Voltages, Coil, and Trimmer Locations Measured with all batteries at normal voltage-Tuned to approximately 1,000 kc- No signal being received-Volume control optional *CAUTION: Do not attempt to measure voltages on control grids of the 6A7, 6D6, or75,w

19、ith any conven- tional voltmeter due to presence of bias cells. Note: Two voltage values are shown for some read- ings.The higher value shown in parenthesis with as- terisk (*)indicates operating conditions without volt- meter loading. Alignment Procedure Calibratethe tuningdialby adjustingdialpoint

20、er to the lowfrequency (end) calibration mark on dial scale with the gang tuning -condenser plates in full -mesh position.This is a friction adjustment. -66V.- PRI. ADJ. V I.F.TRANS. Order of Alignment Test Oscillator Receiver Dial Setting Circuit to Adjust Adjustment Symbols Adjust to Obtain Connec

21、tion to Receiver Dummy Antenna Frequency Setting 1 I -F Amp. Grid Cap .001 Mfd.460 kc No Signal 550-750 kc 2nd I -F Trans. L7 and L8Max. (peak) 2 1st Det. -Osc. Grid Cap .001 Mfd.460 kc No Signal 550-750 kc 1st I -F Trans. L5 and L6Max. (peak) 3Ant. Lead200 Mmfd.1,500 kc1,500 kcA Osc.C6*Max. (peak)

22、4Ant. Lead200 Mmfd.1,500 kc1,500 kcA Ant.C3Max. (peak) * C6 is in two sections. Tighten section on bottom of gang (under chassis) for maximum capacity before adjusting top section. 收音机爱 好者资料库 RadioFans.CN PAGE 38-B 84BT replace sockets with octal type (Stock No. 31251). (b) Connect octal socketsinac

23、cordance with socket connections onthe accompanying diagram. Note that the following circuit changes are necessary: All symbols refer to designations in 84BT Service Notes. (c) Replace oscillator grid resistor (R-1) with a 220,000 ohm resistor (Stock No. 12264). (d) Replace the screen dropping resis

24、tor (R-2) with a 56,000 ohm resistor(Stock No. 12286). (e)Connect I -F screen grid to terminal F on firstI -F transformer (B+) instead of to first detector screen grid. (1)Remove R-9 and C-15; connect R-8(1 megohm) to 2nd detector plate terminal. (g)Replace output grid resistor (R-10) with a 2.2 meg

25、ohm resistor (Stock No. 12679). (h) Remove R-6,all C batteryleads, and yellow lead from R-8 to R-5. (i)Connect a1 megohm resistor (Stock No. 13730) from terminal A on the first I -F transformer to chassis. (j)Remove the first B battery plug and the blue lead and fuse which connect it to the negative

26、 A terminal. (k) Add a fourth wire to the battery cable, connecting to the yellow lead on the second B batteryplug,and through an 820 ohm resistor (Stock No. 14076) to chassis. Thisresistor may be mounted on the terminal board formerly used for R-6. The low end of the 2.2 megohm output grid resistor

27、 should connect to the battery side of the 820 ohm resistor. (1)Remove dial lamp and brown connecting lead. (m) Insert new tubes as follows: 1A7 -G 1st detector -oscillator 1N5 -G I -F amplifier 1H5 -G 2nd detector, A -F, A -V -C 1C5 -G Output (n) Replace tube shields. (o) Realign according to instr

28、uctions in 84BT Service Notes. (p) Make alterations on rating label andin- struction sheet to indicate the change of battery supply and tube complement. (q) Use 1.5 volt dry cell or 1.4 volt Aircell for A supply ;and two 45 volt batteries forB supply. No C batteries are required. MODIFIED84BT CHASSI

29、S Miscellaneous Data MODELS R-93 and R -93A Replacement Pickup Mechanism No. 32205: Thispickupmechanismisavailablefor replacement on record players R-93 and R -93A. ItisidenticalinconstructiontoStockNo. 31100, described below, except that the magnet is chrome instead of cobalt, and the output is app

30、roximately 0.4 volts. R-93, R -93A, R-93-2, R-94, R-96, D7-7, 7U, 7U-2, U-101, U -102E, U-103 Replacement Pickup Mechanism No. 31100: Replacement Pickup Mechanism Stock No. 31100 and 32205. A service replacement pickup mechanism for the midget type tone arm can now be ob- tained by ordering Stock No

31、. 31100-Pickup Unit,less Tone Arm. This unitis usable in the models listed above. Latest design features, including a simple and substantialcentering adjustment,areincorpo- rated in this unit. The cobalt magnet employed assuressufficientoutput(0.6voltsaverage) and correct impedance (1,400 ohms) for

32、all of the specified applications. To adjust, loosen the screws A -A, move theneedle sothatthe armature iscentrally aligned between the pole pieces, and then re -tighten the screws. Check to see that the armature blade is not striking the coilformandthatthecentering springis securely attached to the

33、 armature. MAGNETIC PICKUP MARKINGS Inordertosimplifytheidentificationof ?ickups and proper stock numbersfortheir .:omponents, the various pickup mechanisms to be manufactured for replacement in the future will have stampings similar to the following: PU 32205The first group of numerals in- dicates

34、the stock number of the pickup assembly. A14295The secondgroupofnumerals gives the stock number ofthe armature. C 11732Thethirdgroupofnumerals identifiesthe stock. number of the coil. This marking systemisbeingeffectedat once on pickups No. 32205, No. 31100, No. $2228 and No. 12598. It will be conti

35、nued on anyadditionalreplacementpickupstobe produced. STOCK NO. 14335 Volume Control Connections: The Stock No. 14335, volume control, as used in several models of the 1937-38 line may have any one offour constructional arrange. ments. The differentcontrolsare,however, inter- changeable,both electri

36、callyandmechan- ically.Terminallocationsare showninthe diagram. Terminal No.1isthe low potential end of unit; terminal No. 2is the wiper arm; terminal No. 3 is the high potential end of the unit; and terminal No. 4 isthe tone -compen- sationtap.The illustrationsareasviewed from the front of the cont

37、rol. 123123 123 1Z3 Terminal Arrangement, Stock No. 14335 Volume Control. 1937-38 RECEIVERS Vernier Tuning Drives: Three typesofvernier drives(StockNo. 31641,31640,14514)wereemployedon tuning condensers of the 6-10 tube receivers. These drives are not interchangeable and itis thereforeessential,wher

38、e replacementisre- quired, to order the correct part. Identification may beestablishedbycomparisonwiththe illustrations. These drives are used on the fol- lowing models: 86E86T86K 87T 87K87X87E88K 810T810T4810K 810K1 812XU105 U-107 STOCK 31643 11100 STOCK * 30741 STOCK .14514 4=M2 0 STOCK* 31640 ler

39、nier Tuning Drives for 1937-38 Receivers. NotethatStockNo.14514 supersedes Stock No. 14364. Two typesofvernierdrives (StockNo. 31643,30741)are tobe found on Models 37K1, 87T2, 87K2 and U-106. When order- ingreplacements,thecorrect partmaybe identified by comparison with the drawings. G-8 REMOTE CONT

40、ROL Adapting G-8 Control to 1938-39 Models: The assembly of the G-8 Remote Control Unit can be revised readily, so that itis equivalent to the newer model G-8 A, and may be used with 1938-39 electric tuning receivers.Itis only necessary to voidthflatching feature ofthe push buttons,by either removin

41、g the latch plates entirely or securing them in the open position.Details of the required changes are as follows: (a) Remove contact and latch assembly from case of G-8 by taking out six screws hold- ing base. (b) Disconnect link bar between the two latch plates. (c) Grind or file off outer ends of

42、studs holding the latch plates to support bracket. (d) Removelatchplatesanddiscard. Re- assemble control box. (e) Strip additional 5 inches of braiding from receiver end of remote cable, and shellac braid ends to prevent fraying. As an alternative for operations (b), (c), and (d),the latchplates may

43、 be securedinthe complete open position by tying the lower leverofthe latch plate nearest cable to the support bracket. POPPING INTERFERENCE ReductionofStaticDischarges, AC -DC Receivers: Where AC/DC receivers are used with an external antenna whichisexposedtosteam, smoke,snow,orotherinfluencesofsim

44、ilar nature, a static accumulation may occur on the antenna andwillproduce objectionableinter- ference by discharge to ground, chassis or other nearby objects.This condition can be obviated by connecting a1 megohm resistor in parallel with the isolating capacitor which is normally usedinserieswiththe antennainput,thus maintaining the antenna at ground d -c potential at all times.