RCA-Victor-Co-Inc-28X 电路原理图.pdf

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1、MANUAL OF 1942 MOST POPULAR SERVICE DIAGRAMS $ fHrj sji -y 3g,o D u* S* v9 fc O (9 l-41 fr-S SP _ _ :oTJ a Ig0 “5 |t n 8 two 0 . lO o 3fu? -v!ftAj(g) Tip- aj S*Ss Hlia? O | *)j ?u2u o: a* 2 5 o 0 “ u u 2 ituluj | |sSs lifil jjfsf: Sugc . 4 *szs8 ooozz. TW II 1p z “It III, Jn1 u JV fl , , M!i 1 ?* -

2、r 2 * OZzZZ t 5J ir Um s 85 4+ 58 nnnnp Q -4 -IN 0 |-1 $r- -i_i COMPILED BY M. N. BEITMAN, SUPREME PUBLICATIONS V sp e S3 113 收音机爱 好者资料库 RadioFans.CN MODEL 28X PAGE 429-C MODEL 28c and 28X5 Chassis No. RC -1002 RC -1002-A Eight -Tube, Two -Band, AC -DC Superheterodyne Receiver Electrical and FREQUEN

3、CY RANGES Standard Broadcast 535-1,720 kc Short Wave 8.7-15.6 mc Intermediate Frequency 455 kc TUBE COMPLEMENT (1) RCA-6SG7 R -F Amplifier (2) RCA-6SA7 1st Det.-Osc. (3) RCA-6SK7 I -F Amplifier (4) RCA6SQ7 2nd Det., A.V.C., A.F. Amp. (5) RCA-6SQ7 Phase Inverter (6) RCA-25L6GT Power Output (7) RCA-25

4、L6GT Power Output (8) RCA-25Z6GT Rectifier Dial Lamp (2) Mazda 44, 6.3 V., 0.25 A. DRIVE CORD SHOWN WITH GANG AT MAX. CAPAC ITV 3 TURNS PULLEY 1 / 28X Change in 2nd Production: In 1st production, a capacitor C47 is con- nected from chassis to the junction of R1 and R27 in the RF plate circuit. fn 2n

5、d produc- tion, 1:47 is omitted, and terminal 11 on the oscillator coil is connected to the junction of R1 and R27 instead of to the plus B bus. MODEL 28X5 Mechanical Specification LOUDSPEAKER 92136-2 or 92136-3 Type PM EM Size 9k -inch 9 -inch Ellipticon Ellipticon Voice Coil Impedance at 400 cycle

6、s 4 ohms 3 ohms POWER OUTPUT RATING Undistorted 2.5 watt Maximum 4.0 watt POWER SUPPLY RATING 105-125 A.C. 50.60 cy. or D.C. 45 watts Thermal relay cuts in the dial lampe after the set warms up.- This set incorporates a thermal relay to control the dial lamps. When the set is off, the relay contacts

7、 are closed. This shorts out the two lamps. When the set is turned on, the heater current flows through the relay element R24. This heats up and causes the relay contacts to open, permitting the heater current to flow through the two dial lamps and light them. In normal operation, the lamps light ab

8、out a half -minute after the set is turned on. 28 x 28X, 28X-5 Hum Modulation: This form of hum becomes evident when a stations carrier is tuned in, and disappears when the set is tuned between stations. The hum may be present on only a few locals, or on many stations, depending, among other things,

9、 on the type and installation of the a -c supply line. If hum modulation exists, check to see that there is an .05 mfd., 400 -volt capacitor con- nected from the plate of the 25Z6GT rectifier to -B. Add this capacitor if necessary. The ca pacitor acts to by-pass RF signals around the rectifier tube.

10、 C4 Changed to 47 mmfd: The oscillator grid capacitor is changed iron, :1:1 to 47 nimbi., Stock No. 13141. C30 -ANT. 1300 KC. TO L12 P ONO JACK L23 To 53 To S2 TO Ce TO L11 28X5 Insufficient Push -Button Range: In Model 28X5 if the push -buttons have in- sufficient range, realign IF at exactly 455 k

11、c. If this does not correct the trouble, replace the main oscillator coil Stock No. 38685 and re- align the set. The correct coil has no number stamping; do not use coil stamped 95106-501. 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 430-c 28X,

12、28x5 r Y S o u gij Do/ Qfr WJ eoF *( 3 o m o ,O V1 C ro Ku mN uo i F- - o uo-: uo INg :43 umd. pp 8 Wo ete + NpOp 6f2, J p N T J o Ng o m 收音机爱 好者资料库 RadioFans.CN 2 xo _e W - 1 UN am I- I- am9 NI -tiM,-.-M/I. : L - S a4 e- , n8 0 J e o IUr a as - 01, Oii Q00 h V W / ,Z mx N a N v U 8 ri -8 1.1r II -

13、mo Z J a 1 4 N U CYO r S * 2ijA N 2 I- duilZl W Z ;. NA rt lr o 0: 0 ZZ WQw rieiAe d4 uvp F LJ4O0O s : _Q 2InWI Wo gO = n m- = iYmgm roo u n . 00 IFII _Y7s M, Z V 3VL /?, d -i _ nf izzzz .,. w z gF ii i N m $L 4 ut:. Q4 ooa O N Jr M Fyo J o O n x co N J W J 432-C 28X, 28X5 Alignment Procedure Output

14、 Meter Alignment.-Connect the meter across the voice coil, and turn the receiver volume control to maximum. Test-Oscillator.-Connect the low side of the test -oscillator to the receiver chassis, through a .01 mfd. capacitor, and keep the output Steps Connect the high side of test osc. to- Tune test

15、osc. to- Range Switch to- Turn radio dial to- Adjust the follow- ing for max. peak output as low as possible. Dial Pointer Adjustment-The dial pointer should be set at the left hand end dial marks, with the gang in full mesh. 1 I -F grid in series with .01 mfd. 455 kc A Quiet Point near C36, C37 2nd

16、 I.F. Trans. Critical Lead Dress 1. Dress all AC filament and power wiring down close to chassis and 2 Det. grid in series with .01 mfd. middle of dial C34, C35 1st I.F. Trans. as far as possible from all audio grid or plate wiring. 2. Dress all leads or parts as far as possible away from oscillator

17、 coil. 3. Dress audio coupling capacitor C38 from volume control to grid 3 Ant. lead in series With 15 me C 15 me C-31 (ost.)* C-29 (ant.) of 6SQ7 away from filament wire connecting No. 8 pin socket 5 and No. 8 pin socket 7. 4. Dress lead from trimmer condenser on loop to S.W. ant. coil 4 50 mtnfd.

18、9.5 me C 9.5 me L14 (osc.) L12 (ant.) between rectifier and R.F. tube and away from other coil leads. 5. Dress I -F plate and grid leads back into shield can to keep ex- Repeat steps 3 and 4. posed length as short as possible. L 14 5 1,300 kc A 1,300 kc C-32 (ost.) C-30 (ant.) cs.sMc. , / 6 Antenna

19、terminal in series with 2s= 200 mmfd 600 kc A 600 kc C-33 Rock in C 3c C 2e -3osc 7 Repeat steps 5 and 6. 15 MC. 1300 sc. / 27 R -F / c s3 2 / A osc. 0pe/ - o c. e ,WA 8 grid in series with .01 mfd. 455 kc A low end of dial C-284 *s LIZ-ANT s.sMc._ f servo Ng ,ir,4. TRAP 1 alyiJll ass Kc. ; c 2s .r

20、O O C -ANT. 1ST 1.F 2ND I.F 1s Mc. TRANS TRANS. s *Oscillator should track on high frequency g side of signal. If two peaks are obtained use high frequency (minimum capacity peak). 6567 e Li, *Feed a high signal level of .455 kc into R.F. grid and adjust C-26 for minimum signal. C4 C55 C36 -C37 455

21、Kc. Antenna.-The set is equipped with a built-in loop antenna. If an outdoor antenna is used, it may be connected to the ANT terminal Power -Supply Polarity.-For operation on d -c, the power plug must be inserted in the outlet for correct polarity. If the set does lead-in.o rearof c isnlo It should

22、not be longer than Ica feet,i iin spring not function, reverse the plug. On a -c, reversal of the plug may re- withh Ife it longer, connect a 100 to 200 mmf. capacitor in series duce hum. the lead-in. Replacement Parts Insist on genuine factory -tasted parts, which are readily Identified and may be

23、purchased from authorized deafen. STOCK No. DESCRIPTION STOCK No DESCRIPTION i. 38722 38734 35097 39152 57369 38691 38692 38693 38723 12948 12725 12694 33584 4858 11315 38248 5196 32787 32786 34505 12484 38720 58686 37962 38690 38686 38689 38409 38404 34662 38694 38719 , 38718 38717 11891 31193 3872

24、1 38729 36230 38714 38724 36976 CHASSIS ASSEMBLIES (Model 28X RC -1002) Board-Antenna terminal board Bracket-Drive cord pulley bracket Can-Shield can for let I.F. transformer Capacitor-Electrolytic comprising 1 section of 30 mmfd., 150 volts and 1 section of 100 mmfd , 150 volts Ca pacitor-Comprisin

25、g 1 section of .005 mfd., and 1 section of .0003 mfd. Capacitor-Adjustable capacitor -66-75 mmfd Capacitor-Adjustable capacitor -90-110 mfd m Capacitor-Adjustable capacitor comprising 1 sec- tion of 8-75 mmfd., 1 section of 480-800 mmfd., and 1 section of 5-30 mmfd Capacitor-Mica trimmer -1.5-10 mmf

26、d Capacitor -33 mmfd. Capacitor -150 mmfd. Capacitor -220 mmfd Capacitor-.005 mfd. Capacitor-.01 mfd. Capacitor-.015 mfd. Capacitor-.02 mfd. Capacitor-.035 mfd. Capacitor-.05 mfd. Capacitor -0.1 mfd. Capacitor -0.2 mfd. Capacitor -0.25 mfd. Clip-Spring clip for dial scale Coil-Antenna coil Coil-Ante

27、nna coupling coil Coil-Filter coil Coil-Oscillator coil Condenser-Variable tuning condenser Control-Tone control Control-Volume control and power switch Cord-Drive cord (approx. 59 -in. overall length) Core-Adjustable core and stud Dial-Glass dial scale Drum-Condenser drive drum Indicator-Station se

28、lector indicator Lamp-Dial lamp Lead-Antenna lead Loop-Antenna loop complete-less antenna coup- ling transformer Plate-Dial back plate only-less support brack- eta, pulley bracket and pulleys Pulley-Drive cord pulley Relay-Thermal relay Resistor-Wire wound comprising 2 sections of 60 ohms each Resis

29、tor -88 ohms, 1 watt 12071 12287 6134 14075 3078 30450 30650 13715 14680 14683 12486 30271 90271 38785 12071 38715 39087 a787 37805 31418 12007 36098 38733 38752 38727 38713 36232 37364 33726 38716 38736 39484 38736 39483 38738 36886 36722 30900 Resistor -120 ohms, watt Resistor -1,200 ohms, X. watt

30、 Resistor -1,200 ohms, 1 watt Resistor -8,200 ohms, X. watt Resistor -10,000 ohms, watt Resistor -22,000 ohms, watt Resistor -68,000 ohms, watt Resistor -68,000 ohms, watt Resistor -100,000 ohms, watt Resistor -220,000 ohms, X. watt Resistor -560,000 ohms, watt Resistor -4.7 meg., watt Resistor -4.7

31、 meg., watt Resistor -16 meg., watt Resistor -120 ohms, watt Shaft-Tuning knob abaft Socket-Dial lamp socket Socket- input socket Socket-Tube socket Spring-Drive cord spring Spring-Retaining spring for core and stud Spring-Used to hold 1.F, transformers in shield Cain Support-Left hand dial plate su

32、pport Support-Right hand dial plate support Switch-Range switch Transformer-Audio transformer Transformer-First I.F. transformer-leas shield can Transformer-Second I.F. transformer-less shield can Washer-C washer for tuning shaft Washer-Spring washer for tuning shaft SPEAKER ASSEMBLIES (92136-2) Con

33、e-Cone complete with voice coil SPEAKER ASSEMBLIES (92136-3) Coil-Field coil 2,500 ohms Cone-Cone complete with voice coil Plug -3 -prong male plug MISCELLANEOUS ASSEMBLIES Decalcomania-Control panel decal-Pkg. 5. Knob-Range switch knob Knob-Tuning, volume control or tone control knob Spring-Retaini

34、ng spring for knobs PAGE 433-C 28X, 28X5 Replacement Parts MODEL 28X-5 Insist on genuine factory -tested parts, which are readily identified and may be purchased hom authorized dealers. STIOoCK DESCRIPTION STOCK DESCRIPTION CHASSIS ASSEMBLIES (Model 28X5 RC -1002A) 38729 Plate-Dial back plate only-l

35、ess support bract - ets, pulley bracket and pulleys 38722 38734 Board-Antenna terminal board Bracket-Drive cord pulleybracket 36230 38714 38724 Pulley-Drive cord pulley Relay-Thermal relay Resistor-Wire wound comprising 2 sections of 35097 Can-Shield can for 1st I.F. transformer 50 ohms each 39152 C

36、apacitor-Electrolytic comprising 1 section of 36976 Resistor -68 ohms, 1 watt 30 mmfd., 150 volts and 1 section of 100 12071 Resistor -120 ohms, watt mmfd., 150 volts 12267 Resistor -1,200 ohms, 4 watt 37359 Capacitor-Comprising 1 section of .005 mfd., 6134 Resistor -1,200 ohms, 1 watt and 1 section

37、 of .0003 mid. 34767 Resistor -2,200 ohms, watt 38691 Capacitor-Adjustable capacitor -55-75 mmfd. 14075 Resistor -8,200 ohms, 4 watt 38692 Capacitor-Adjustable capacitor -90-110 mmfd. 13998 Resistor -22,000 ohms, i watt 38693 Capacitor-Adjustable capacitor comprising 1 sec- 30650 Resistor -56,0001 o

38、hms, i watt tion of 8-75 tumid., 1 section of 480-600 13715 Resistor -68,000 ohms, watt mmfd., and 1 section of 5-30 mmfd. 14560 Resistor -100,000 ohms, watt 38723 Capacitor-Mica trimmer -1.5-10 mmfd, 14583 Resistor -220,000 ohms, * watt 38726 Capacitor-Mica trimmer comprising 1 section of 12486 Res

39、istor -560,000 ohms, watt 10-160 mmfd., 2 sections of 25-250 mmfd., 1 30649 Resistor -2.2 meg., watt section of 50-400 mmfd., and 1 section of 100- 30271 Resistor -4.7 meg., 3 watt 540 mmfd. 38785 Resistor -15 meg., watt . 12948 Capacitor -33 mmfd. 38715 Shaft-Tuning knob shaft 39540 Capacitor -51 m

40、mfd. 39087 Socket-Dial lamp socket 12725 Capacitor -150 mmfd. 35787 Socket-Phono input socket 12694 Capacitor -220 mmfd. 37605 Socket-Tube socket 30433 Capacitor -470 mmfd. 31418 Spring-Drive cord spring 33584 Capacitor-.005 mfd. 12007 Spring-Retaining spring for core and stud . 11315 Capacitor-.015

41、 mfd. 35098 Spring-Used to hold I.F. transformers in shield 36248 Capacitor-.02 mfd. cans . 5196 Capacitor-.035 mfd. 38731 Support-Left hand dial plate support 32787 Capacitor-.05 mfd. 38730 Support-Right hand dial plate support 32788 Capacitor -0.1 mfd_ 38712 Switch-Range switch 34505 Capacitor -0.

42、2 mfd. 38725 Switch-Selector switch 12484 Capacitor -0.25 mfd. 38713 Transformer-Audio transformer 38720 Clip-Spring clip for dial scale 36232 Transformer-First I.F. transformer-less shield 38813 Coil-Antenna coil can 37962 Coil-Antenna coupling coil 37364 Transformer-Second I.F. transformer - less

43、38690 Coil-Filter coil shield can 38685 Coil-Oscillator coil 33726 Washer-C washer for tuning shaft 37838 Coil-P.B. oscillator coil -540-1,100 K.C. . 38716 Washer-Spring washer for tuning shaft 35803 Coil-P.B. oscillator coil -610-1,250 K.C. . 38772 Coil-P.B. oscillator coil -750-1,420 K.C. . SPEAKE

44、R ASSEMBLIES 38773 Coil-P.B. oscillator coil -950-1,560 K.C. . (92136-2) 38889 Condenser-Variable tuning condenser . 38409 Control-Tone control 38736 Cone-Cone complete with voice coil 38404 Control-Volume control and power switch . 34862 Cord-Drive cord (approx. 60 -in, overall length) MISCELLANEOU

45、S ASSEMBLIES 38694 Core-Adjustable core and stud 35871 Core-Adjustable core and stud for P.B. oscil- 38737 Bezel-Push button bezel lator coils 38375 Button-Push button 38728 Dial-Glass dial scale 38739 Decalcomania-Control panel decal-Pkg. 6 . 38718 Drum-Condenser drive drum 38886 Knob-Range switch

46、knob 38717 Indicator-Station selector indicator 36722 Knob-Tuning, volume control or tone control 11891 Lamp-Dial lamp knob . 31193 Lead-Antenna lead 34317 Marker-Station selector marker 39514 Loop-Antenna loop complete-less antenna 30900 Spring-Retaining spring for knbbs coupling transformer 34053

47、Spring-Retaining spring for push button 2 8X5 95O 750 750 GIO 540 To ._ To - TO To -7%i TO. (;db 560 1420 1420 12S0 1100 KC OSCILLATOR ADJUSTMENTS ZgxS Push Button The station push buttons connect to separate magnetic -core oscil- lator coils and separate antenna trimmers which must he adjusted for the desired stations. Use an insulated screwdriver or alignment tool such as RCA Stock No. 31031. Allow at