RCA-Victor-Co-Inc-VA-20 电路原理图.pdf

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1、PA3E 392-C MODELS VA -20 and VA -21 Two -Tube, A -C, Wireless Record Players MO DEL VA -20 MODEL VA -2I Electrical and Mechanical Specifications FitEQCENCY RA NOR 530-625 kc PICHIIP ltBE COMPLEMENT Type Crystal (1 I R(A-6A1( Modulator -Oscillator Pickup Impedance 100,000 oh,ns at 1000 cycles (2) RCA

2、 -25Z0 -G Half -Wave Rectifier Average Output Voltage 11 volts at 1000 cycles Dial Lamp lazda 47, 6-8 volts, .15 .nip, with 250,000 ohm load. POWER SUPPLY RATINGS A-6 A-5 CABINET DIMENSIONS Height 3 inches Width 121 inches MOTOR Depth 81 inches Over -All Height 5 inches Type Synchronous (Manual Star

3、ting) Turntable Diameter 7 inches Turntable Speed 78 r.p.m. A*eight 71 lbs. (net), 91 lbs. (shipping) 105-125 volts, 60 cycles, 50 watts 105-125 volts, 50 cycles, 50 watts Set -Up Procedure 1. Insert plug in power supply outlet, and turn the power- switch-volume control knob on top of VA -20 to full

4、 clockwise position. Start a record on the VA -20. The motor is a synchronous manual -starting type, and requires a clockwise spin to start. 2. Tune the radio receiving set to a quiet point between 530- 625 kc. :3. Tune the oscillator in the VA -20 to this frequency by adjust- ing the button on the

5、rear of the VA -20 cabinet to obtain peak output on the receiver. Clockwise rotation decreases the frequency; counter -clockwise rotation increases the frequency. 4. Adjust the radio volume control for the highest volume that is likely to be required, and then use the VA -20 volume control for furth

6、er adjustment. 5. In noisy locatioris, it may be desirable to leave the VA -20 volume control turned full clockwise, and regulate the radio volume control for the desired level. 6. If there is insufficient volume, or excessive noise, the remedy is to couple the VA -20 to the radio receiver, by runni

7、ng a piece LEATHER WASHER SHOULD BE OIL SOAKED. GOES ABOVE STEEL WASHER. OIL BALL BEARI NG USE LIGHT OIL TURNTABLE MELD ON SHAFT BY RETAINING RING B WASHER AIR GAP Is .016 .0007E GAP MUST BE UNIFORM. OIL OUTER BEARING SURFACE,USE LIGHT OIL. OIL INNER BEARING SURFACE. USE LIGHT OIL. of insulated wire

8、 between the two units: V. rap one enu (three or four turns) around the antenna lead-in on the radio, and wrap the other end (three or four turns) around the short wire that projects from the plug on the power cord of the VA -20. With an RCA Master Antenna, wrap the wire around the counter -poise le

9、ad where it attaches to the receiver (terminal A3) or to the coupling unit (terminal B). 7. If the radio receiver has push-button tuning, one of the buttons may be set up to tune in the VA -20 oscillator frequency. This button should be marked Record Player. Motor Data Smooth starting and running wi

10、ll be insured by keeping the bearings well cleaned and oiled. Hum and Vibration.-A small amount of hum when starting, decreasing to a negligible amount when running, is normal. If excessive vibration occurs it may be due to: 1. Insufficient lubrication, or any failure that will cause binding. 2. Lea

11、ther washer not oiled. (Check to make certain that the leather washer is above the steel washer.) 3. Motor not properly supported from motor board. 4. Burrs on poles of rotor or stator. Remove with fine emery cloth. *Note: Voltages with star (0) ate operating voltages in circuits with high series re

12、sistance. The actual measured voltage will be lower, depending on the voltmeter loading. Voltages are measured to chassis, unless otherwise indicated. Values should hold within approximately 20% with 117 -volt a -c supply. Precautionary Lead Dress 1. The power supply cord must be dressed between cha

13、ssis and top of cabinet, away from grid of 6A8, and entirely away from 25Z6 -G. 2. All leads to oscillator coil must be as short as possible. 3. All motor leads must be dressed away from rotor. 4. Pickup leads must be dressed away from the top grid of 6A8, and kept away from the 25Z6 -G. Caution: Do

14、 not remove turntable from motor while power is turned on, as damage to the tubes will result. RED BLACKS , PILOT LAMP YELLOW( S14906 L -J YELLOW RED 50 -Cycle Motor Coil Assembly and Connections D -C resistance of each coil: 105-125 volts, 60 cycles 36 ohms 105-125 volts, 50 cycles 40 ohms RCA VICT

15、OR DIVISION OF RADIO CORPORATION OF AMERICA, CAMDEN N. J., U. S. A. 收音机爱 好者资料库 RadioFans.CN PAGE 393-C Over -Modulation or Distortion: On some records, and particularly with pick- up units having relatively high voltage output, an occasional case may be encountered when distortion occurs at advanced

16、 volume control (VA -20) settings. This condition can be elimi- nated by effecting the following circuit changes: Remove: Self bias resistor R-2 and associated by- pass capacitor C-4 from cathode circuit of 6A8 modulator -oscillator stage. Install: (a) Connection between 6A8 cathode (K) and shell (S

17、H) (or chassis). (b) A 10 megohm resistor Stock No. 13601 between modulator grid and cathode (K) on 6A8 socket (or chassis). (e) A .0025 mid capacitor Stock No. 5107 in series with green lead from arm of volume control to modulator grid. (I) A 120,000 ohm resistor Stock No. 13734 across the volume c

18、ontrol from terminal 1 to terminal 3. The overmodulation condition can also be avoided by operating the VA -20 volume control at a retarded position, and regulating volume by means of the receiver control. The above changes however, effect a foolproof cure, and should be incorporated on any instrume

19、nts being serviced. These changes are incorporated in later production instruments. 6A 8 MODULATED OSC. W t7t.MA. m a U - C2 56MMF n z RI 47,000 1 C4 0.1 MFD. MODEL VA -20 Additional Replacement Parts: Stock No. 33041 Ring-Retaining ring and metal washer to mount turntable plate 5107 Capacitor-.0025

20、 mid. capacitor (C10) 13734 Resistor -120,000 ohms (R8) 13601 Resistor -10 megohms (R7) Change in 50 -Cycle VA -20: Late production of 50 -cycle models have a 110 -volt motor, and a ballast resistor in series with the heater circuit as shown in the accom- panying schematic. The following parts apply

21、 to the late 50 -cycle instrument: Stock No. 31034 Motor -110 volt, 50 cycle, less mounting 31037 Rotor-Turntable and rotor lamina- tion assembly complete for 50 -cycle operation 31043 Stator-Stator assembly complete with coils and laminations for 50 - cycle operation 33484 Resistor-Ballast resistor

22、, 1.24 ohm and 1-271 ohm sections for heater circuit (R10, R9) R3 56 000- /1 C5 0.1 MFD. 1.72MA. hike: O R4 C9 _ O.I, .111 33000 MU. - FREQ. ADJ. C6._!_ C7 530-6251(C 15 15 MFD.I MFD. I r1-86596-5 VA -20 Insist on genuine rectory -testad 25Z6 -G RECT. VA -20, VA -21 Motor Inter -Lock Switch: An inte

23、rlock switch has beets added to motor hase on these models, and is connected in series with the motor supply. This switch opens whenever the turntable is removed, and obviates tube damage. Replacement parts as listed in Service Notes apply except as noted below: Omit Stock No. :11046 Bearing Assembl

24、y. Add Stock No. 35003 Ball-Steel ball for rotor bearing. 35002 Bearing-Rotor bearing assembly- less ball 35004 Plunger-Hard rubber plunger for motor switch 35001 Switch-Motor switch complete. Changing Frequency Range: Should it be desirable to employ a different range of- frequency on the VA -20 Wi

25、reless Rec- ord Player, this may be accomplished readily by removing turns from the oscillator coil. The resultant frequency range for given num- ber of removed tarns are: Turns Removed 8 117V.AC Ri Frequency Range 580 kc - 710 kc 16 630 kc - 770 kc 24 700 kc - 850 kc 32 760 kc . 940 kc 40 850 kc -

26、1,.050 kc 48 960 kc 1,200 kc 56 1,100 kc - 1,400 kc 64 1,300 kc - 1,650 kc 648-. 6.4v AC 560,000 6 2526-4 5.4v. AC 250,000o . (Pici4u 3 L4 RED YELLOW RED 1 , BLACK YELLOW M-1 r BSY. qC PILOT LAMP 51 oN REAR OF VOL. CONTR.) 1(- 6On.MOTOR CONN. Replacement Parts Model VA -20 parts, which are readily i

27、dentified and may be purchased horn authorized dealers. STOCK No. DESCRIPTION STOCK No. DESCRIPTION 13103 32642 31051 32611 30885 31480 31053 32500 12993 31385 32499 12723 12694 4839 32152 32501 12262 12454 12412 12286 12486 31251 MISCELLANEOUS ASSEMBLIES Cap-Pilot lamp cap (bullseye) Cord -Power an

28、d output cord and plug Foot-Rubber foot for cabinet Knob-Special knob to adjust oscillator coil Knob-Volume control and switch knob Lamp-Pilot lamp Mounting-Motor mounting screws and washers complete Mounting-Pickup arm mounting ring and rub- ber cushion Screw-No. 8-32 x 1 -inch headless set screw f

29、or knob Socket-Pilot lamp socket Volume control and switch (R6, S1) OSCILLATOR ASSEMBLIES Capacitor -56 mmfd. (Cl, C2) Capacitor -220 mmfd. (C3) Capacitor -0.1 mfd., 400 V. (C4, C5, C8, C9) Capacitor -15 mfd. (C6, C7) Coil-Oscillator coil (L1, L2) Resistor -680 ohms, watt (R2) Resistor -33,000 ohms,

30、 watt (R4) Resistor -47,000 ohms, # watt (R1) Resistor -58,000 ohms, watt (R3) Resistor -560,000 ohms, 4 watt (R5) Socket-Tube socket 32507 31046 31041 32645 32505 31047 32643 32508 31040 32644 32506 32917 32916 31039 4083 14231 31049 31050 9842 12539 MOTOR ASSEMBLIES Base-Motor support, damper, and

31、 bearing cup assembly Bearing-Bearing assembly Cap-Rubber spindle cap Coil-Motor field coil for 85 -volt, 50 -cycle op- eration-less laminations Coil-Motor field coil for 85 -volt, 60 -cycle op- eration-less laminations Cushion-Rubber cushion for bearing Motor -85 -volt, 50 -cycle (M1) Motor -85 -vo

32、lt, 60 -cycle (M1) Mountings-Turntable top rubber mountings suf- ficient for one turntable Rotor-Turntable plate and rotor lamination as- sembly complete for 50 -cycle operation Rotor-Turntable plate and rotor lamination as- sembly complete for 60 -cycle operation Stator-Stator laminations and field

33、 coils for 85 -volt, 50 -cycle operation Stator-Stator laminations and field coils for 85 -volt, 60 -cycle operation Turntable-Finished- turntable top plate only- less rubber mountings Washer-Leather washer Washer-Metal spacing washer PICKUP AND ARM ASSEMBLIES Base-Pickup arm pivot shaft and base as

34、sembly Crystal-Pickup crystal and needle screw Pickup crystal and arm complete with mounting Screw-Pickup needle screw 收音机爱 好者资料库 RadioFans.CN PAGE 394-C VA -20, VA -2I REVISED MODEL VA -20 IS ELECTRICALLY IDENTICAL TO MODEL VA -2I (Including changes to prevent over modulation or distortion) 6A8 MOD

35、ULATED OSC. m w C2 S 56M z R1 47,Ooo I Cl R7 i et 56MMF1tM RED YELLOw1 ,RED 84n YELLOW L3 82n 262PILOT LAMP- /INN +US 6 -i 2-71 24n 50 rV MOTOR COHN. M-86596-9 JR3 56 000. 1 C5 I 0.1 M FD. 11 , 72, L2 n 9 ,0 ln - C3 2TT Co to MMF1 R4 = X 1 33poo- FREq. ADJ. ,1 C6ti Cl -.IL.! 530-623KC 15 t5 MFD, MFD

36、. VA20 -_ -_ II C10 oOtS MFR 456V.-se 1.72MA. R8 I2o,000 25Z6 -G RECT. C9 MFDIli, - T MODEL VA -21 VOLTAGES SHOULD HOLD WITHIN 20% WITH 117V AC. SUPPLY. * MEASURED WITH CHANALYST OR VOLTOHAAYST 117V.AC. 6A8 6.0 AC f5,000 R6 25Z6- 5.6 G tells V. I 2g0,000 2 d CPICKUP_ ,L4 CB , r I 36 O.1 RE YELLOW1 R

37、ED MFD. i ,I,cl. 1 e1_ 1 !_ ,te, Mo7R LLOW I.S2 PILOT LAMP 85V. AC Si (ON REAR OF VOL. CONTR.) 60.MOTOR CONN. Replacement Parts MODEL VA -21 Insist on genuine Factory -tested parts, which are readily identified and may be purchased from authorized dealers. STOCK DESCRIPTION STo. OCK DESCRIPTION MISC

38、ELLANEOUS ASSEMBLIES MOTOR ASSEMBLIES 19103 Cap-Pilot lamp cap (bullseye) 32654 Ball-Bearing ball only . . 32642 Cord-Power and output cord and plug 32507 Base -Motor support, damper, and bearing cup assembly 35467 31051 Decalcomania-RCA-Victrola decal Foot-Rubber foot for cabinet 31046 31041 Bearin

39、g-Bearing assembly Cap-Rubber spindle cap 32611 Knob-Special knob to adjust oscillator coil. 31918 Coil-Motor field coil for 110 volts, 50 cycle 30885 Knob-Volume control and switch knob 32505 Coil-Motor field coil for 110 volts, 60 cycle. 31480 Lamp-Pilot lamp. 31047 Cushion-Rubber cushion for bear

40、ing 31053 Mounting-Motor mounting screws and washers 33653 Frame-Rotor frame -50-60 cycle complete 33354 Lamination-Stator lamination-less coils -50 35609 Mounting-Pickup mounting grommet, nut and cycle lockwasher 34961 Lamination-Stator lamination-less coils -60 33484 Resistor-One section 24 ohms,

41、and one section cycle 271 ohms (50 cycle) 33656 Lamination-Rotor lamination -60 cycle 32317 Screw-No. 8-32 x 7.32 headless set screw for 31034 Motor -110 volts, 50 cycle (M1) less mounting knob 32508 Motor -110 volts, 60 cycle (M1) 31365 Socket-Pilot lamp socket 31040 Mountings-Turntable top rubber

42、mountings suffi - 92499 Volume control and switch (R6, S1) cient for one turntable 35004motor Plunger-Hard rubber plunger for switch on 31037 Rotor-Turntable plate and rotor lamination as- sembly complete for 50 cycle operation base OSCILLATOR ASSEMBLIES 31043 Stator-Stator laminations and field coi

43、ls for 110 volts, 50 cycle operation 12723 Capacitor -56 mmfd. (C1, C2) 31039 Turntable-Finished turntable top plate only - 12694 Capacitor -220 mmfd. (C3) less rubber mountings 5107 Capacitor-.0025 mfd 4083 Washer-Leather washer 4839 Capacitor -0.1 mfd., 400 volts (C5, C8, C9). 14231 Washer-Metal s

44、pacing washer 32152 Capacitor -15 mfd. (C6, C7) PICKUP AND ARM ASSEMBLIES 32501 Coil-Oscillator coil (L1, L2) 12454 Resistor -33,000 ohms, 4- watt (R4) 33591 Arm-Pickup arm only-less cartridge, base and 12412 Resistor -47,000 ohms, watt (R1) cable 12286 Resistor -56,000 ohms, watt (R3) 34481 33422 A

45、rm-Pickup pivot arm and shaft Base-Pickup mounting base 13734 Resistor -120,000 ohms, watt 33122 Crystal-Pickup crystal cartridge and needle 12486 Resistor -560,000 ohms, watt (R5) screw 13601 Resistor -10 meg., i watt 34311 Ring-Retaining ring for pivot shaft 31251 Socket-Tube socket 33529 Screw-Needle screw 收音机爱 好者资料库 RadioFans.CN