RCA-Victor-Co-Inc-28T 电路原理图.pdf

《RCA-Victor-Co-Inc-28T 电路原理图.pdf》由会员分享，可在线阅读，更多相关《RCA-Victor-Co-Inc-28T 电路原理图.pdf（9页珍藏版）》请在收音机爱好者资料库上搜索。

1、COMPILED BY M. N. BEHMAN, SUPREME PUBLICATIONS 收音机爱 好者资料库 RadioFans.CN PAGE 425-C MODEL 281 Eight -Tube, Chassis No. RC -569 Three -Band, A -C, Superheterodyne Receiver Electrical and Mechanical Specifications FREQUENCY RANGES A Standard Broadcast 540-1600 ke B Medium Wave 2,300-6,300 kc C Short Wav

2、e 9,400-15,400 kc INTERMEDIATE FREQUENCY 455 kc TUBE COMPLEMENT (1) RCA-6SK7 R -F Amplifier (2) RCA-6SA7 1st Det.-Osc. (3) RCA-6SK7 I -F Amplifier (4) RCA-6SQ7 2nd-Det. A.V.C.-A.F.-Amp. (5) RCA-6SQ7 Phase Inverter (6) RCA-6K6GT Power Output (7) RCA-6K6GT Power Output (8) RCA-5Y3G Rectifier DIAL LAMP

3、 (2) . Mazda No. 51 6-8 volt 0.2 amps. POWER SUPPLY RATINGS 105-125 volts, 50-60 cycles 90 watts 105-125 volts, 25-60 cycles 90 watts PUSH-BUTTON RANGES One station between approximately 540-1,030 kc. Two stations between approximately 610-1,250 ke. Two stations between approximately 740-1,430 kc. O

4、ne station between approximately 880-1,600 kc. Push Button Adjustment Six station push buttons connect to separate magnetite -core oscil- lator coils and separate antenna trimmers which must be adjusted for the desired stations. Use an insulated screwdriver or alignment tool such as RCA Stock No. 31

5、031. Allow at least five minutes warm- up period before making adjustments. In the event that the receiver is to be used with an external an- tenna use one or two feet of wire (as an antenna) to ensure sharp peaking during the final adjustment procedure. For loop operation, the link should be strapp

6、ed across terminals on back of set. In either case the procedure is as follows: 1. Make a list of the desired six stations, arranged in order from low to high frequencies. 2. Turn the range selector to A band, and manually tune in the first station on the list. 8. After turning range selector to PB

7、position, push in station button No. 1 (extreme left). Then adjust the No. 1 oscillator core to receive the station. It may be necessary to maintain POWER OUTPUT RATING Undistorted 4.5 watts Maximum 5.5 watts LOUDSPEAKER (92196-3) Type 9x6 inches elliptical, electrodynamic V.C. Impedance 4.4 ohms at

8、 400 cycles Height Width Depth CABINET (Inches) 123 . 18 . 10 Chassis Base (inches) 22 . 16 . 62 Chassis Height (inches) 102 Weight 27 -lbs. (shipping) 23 -lbs. net Tuning Drive Ratio 15 to 1 680 TO 1600 KC TRIMMER SCREW 6 CORE RODS I 740 TO 1430 1 610 TO 1760 I 840 TO KC I KC 110DOKC I I 5 4 I 3 2

9、1 O 0 I 0 0 I. 0 approximate tracking between antenna and oscillator to receive weak stations. 4. After oscillator core is adjusted properly, adjust trimmer No. 1 for maximum output. Clockwise adjustment of cores and trimmers tunes the circuits to lower frequencies. 5. Adjust for each of the five re

10、maining stations in the same manner. 6. Make a final careful adjustment of the oscillator cores and antenna trimmers. O 10 20 30 40 50 80 70 80 90 100 110 120 130 140 150 160 170 180 I1111 POLICE AIRCRAFT 90M SPECIAL 2.3 . 1 STA DARD C SHORT WAVE 2.5 3.0 3.5 1 I I 1 1 I I 1 1 AMATEUR 60M AIRCRAFT 49

11、M 4.0 5.0 0 BOSTON LONDON SERVICES 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1. 1 1 1 1 1 1 55 60 70 80 100 1 a 1 1 1 1 1 1 1 1 1 l 1 l 1 1 I l l 1 1 1 l 1 1. l 1 9.3 1 l 31M ANKARA HONG K.SCNENr MIGO. IOKYO RUE NOS LONDON SIR LI N NEW .DIY I 1 1 1 1 10 t 1 1 1 1 1 120 140 160 l 141 1 l 1.1 1 1 1 1 25M I I

12、BOSTON i 2w I 3 1 lei 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 gcxt vtGZe AMATEUR 19M 14 15 TOKYO Stills LONDON 1 1 1 1. 1 1 1 . 1 1 A BRORDCRST C If1TERf1ATIOf1Al IIII11111111IIIIIIIIl1111111111111IIIIIIIII1111II111111111 1111111111111I11111111i1IIlII111111111111lIIIIII1111111111111lIIIIlIIIIlIIIIlIIIiIIlIlI1

13、111111111111111111Ii11iI1111111111 O 10 20 30 40 50 60 70 80 90 100 110 120 30 140 150 160 170 180 RCA VICTOR DIVISION OF RADIO CORPORATION OF AMERICA, CAMDEN N. J., U. S. A. J 收音机爱 好者资料库 RadioFans.CN PAGE 426-C 28T C17-COSC. 711COIL/ 1 5. MC. Alignment Procedure Cathode -Ray Alignment is the prefer

14、able method. Connections for the oscillograph are shown in the schematic diagram. Output Meter Alignment.-If this method is used, connect the meter across the voice coil, and turn the receiver volume control to maximum. Test-Oscillator.-For all alignment operations, connect the low side of the test

15、-oscillator to the receiver chassis, and keep the output as low as possible to avoid a -v -c action. Electronic Voltmeter.-The electronic voltmeter in the Chanalyst or VoltOhmyst provides an unexcelled output indicator. It should be connected to the AVC bus, and the test -oscillator output adjusted

16、to produce several volts of AVC. Calibration for Alignment.-The dial calibration for alignment pur- poses can be set up in two ways: 1. The dial may be very easily removed from the cabinet. The condenser plates should then be turned into full mesh, the pointer adjusted to the scratch at the left end

17、 of the dial back- ing plate, and the dial placed on the frame so that its extreme left calibration mark coincides with the pointer. The dial may be held in place with scotch tape. In this manner the actual receiver dial is used, for alignment. When alignment is finished, the scale should be replace

18、d. 2. A calibration scale is attached to the tuning drum. The correct setting of the gang, in degrees, for each alignment frequency is given in the alignment table. Check the position of the drum, making sure that the 0 degree scale mark is horizontal with the gang in full mesh. Pointer for Calibrat

19、ion Scale.-If method (2) is used, improvise a pointer for the calibration scale by fastening a piece of wire tq the chassis, and bend the wire so that it points to the 0 degree mark on the calibration scale when the plates are fully meshed. External Antenna.-For best reception on C band with an out-

20、 side antenna, adjust C2 for peak output on a station in the 31 -meter band. C9 -A DET 1500 KC. C IO- B DET. 6.1 MC. C I1- CDE T 15.2 MC. C3- 8 ANT 6.1 MC. C1-CANT. 15.2 MC. C12 2C DE T. 9.5 MC. C19- OSC. 1500 KC. C t8- B5C. 6.1 MC. BOTTOM VIEW Steps Connect the high side of thefor test-sc.to- Tune

21、test osc. to- Turn radio dial to- Adj. the following max. peak output 1 I -F Grid in series with .01 mfd. 455 kc A Band Quiet Point between 550-750 kc L-15 and L-16 2nd I -F Trans. 2 Det. Grid in series with .01 mfd. L-13 and L-14 1st I -F Trans. 3 Ant. terminal in series with 200 mmfd. open) 1,500

22、kc 1500 kc (160) A Band C-19 (osc.) C-9 (Det.) C-5 (on loop) 4 600 kc 600 k (30.50) L-12 Rock Gang 5 Repeat (3) and (4) 6 Ant. terminal in series with 22 mmfd. (link open) 6,100 kc 6,100 kc (161) B Band C-18 (osc.) Rock G a C-3 (ant.) 7 15,200 kc 15,200 kc (167 C Band C-17 (ose.). C-11 (Det.) Rock G

23、ang C-1 (ant.) 8 9,500 kc 9,500 kc (50 6) C-2 (ant.) C-12 (Det.) Rock Gang 9 Repeat (7) and (8) *Use minimum capacity peak if two peaks can be obtained. Note-Oscillator tracks 455 kc above signal on all bands. PNOND DIO OiT M1lT 2,a de OeF LOUD SMCCM POWER-VOLU ME RADIO -PROMO CONTROL TONE CONTROL 4

24、111 Y:00R-4411) TiEwi Ic ,10 MEDIUM YNVL- STI*1DM0 N,0aOCMT-Y TUNING RANGE CONTROL CONTROL Precautionary Lead Dress. - 1. Dress shielded lead from diode filter to tone control switch away from grid of the 6SQ7 a -f amplifier. 2. Dress shielded lead from grid of 6SQ7 a -f amplifier away from diode ou

25、tput system. 3. Power leads to rear of volume control should be dressed towards side apron. 4. Plate leads on output tubes should be dressed towards chassis. CATHODE CURRENTS (1) GSK7 - - - - 15.5 (2) 65A7 - - - - 8.8 (31 GSK7 - - - - 14.3 (41 65Q7 - - _ _ .31 (5) 6507 - - - - .36 (6) 6K6GT - - - -

26、21.4 (7) 6K6GT - - - 21.4- (8) TOTAL RECT. - - 8 2. 2 收音机爱 好者资料库 RadioFans.CN 4 W 13 1- F w -p 0 o d I a co X i * a Y f60 Q NM N O N toO_ N 0 LL di d LL -I l p m . -z _i 0,90 fms=s I- j *N a o n J oQ- L- 4 / / NN NW a F U o O- o: - H1 v0_ .l P H,. f ao W r a 1m O:.5 N O. 603 h as O u n o *N co a d (

27、.9 N M U . dm In T O Cr c0 -1H v/-i 02 t.o 11, /stik, H _ .= , 7_ N 11 r0 UN a m mo U % 00 N o u_ N FMB ) a3 1N 4,1 )112 d F. J9 -O , li. s z b u QmQ - N 11 n + e h r B iI. -1.9e 4p I N J d 1 4J ( 0 -I OD 99 _o QS, JS9bJbB 2 N PAGE 427-C 281 z zo O MM r yJ PAGE 428-C 28T 1 DIAL POINTER 0 _- i 0 I I

28、I ANTENNA-GROUND , , -, 1 PULLEY ( TERMINAL BOARD : 3 : LINK PUSH BUTTON) TRIMMERS 1 tas DRIVE CORD I SHOWN WITH GANG DRIVE CORD DRUM O AT MAX. CAPACITY SPRING 3 TURNS Insist on genuine factory Replacement -tested parts, which are readily PHONO-TELEV.-FM. POWER CHASSIS JACK CORO Parts identified and

29、 may be purchased from authorized dealers. STOCK No. DESCRIPTION STOCK No. DESCRIPTION 34025 33014 38368 38357 38363 35791 36424 38360 12814 14021 12948 13057 12720 34699 34700 13003 12694 38830 38831 30882 30303 33584 4937 36248 32787 4839 31581 36031 38358 38315 37638 38366 38364 38404 34662 35788

30、 35871 38359 38361 38365 31580 CHASSIS ASSEMBLIES (RC -569) Board-Antenna-Ground board. Capacitor-Electrolytic, comprising 3 sections of 10 mid., 450 volts, and 1 section of 20 mid., 25 volts Capacitor-Adjustable trimmer (50-350 mmfd.) tor antenna coil Capacitor-Mica trimmer -2-20 mmfd. Capacitor-Mi

31、ca tnmmer comprising 2 sections of 8-80 mmfd. Capacitor-Mica trimmer comprising 3 sections of 8-80 mmfd. Capacitor-Mica trimmer comprising 1 section of 10-160 mmfd., 2 sections of 25-250 mmfd., 2 sections of 50-400 mmfd., and 1 section of 100-540 mmfd. Capacitor-Mica trimmer comprising 1 section of

32、50-350 mmfd., 1 section of 5-50 mmfd., and 2 sections of 2-20 mmfd. Capacitor -5.6 mmfd. Capacitor -22 mmfd. Capacitor -33 mmfd. Capacitor -68 mmfd. Capacitor -100 mmfd., moulded Capacitor -100 mmfd., unmoulded Capacitor -120 mmfd. Capacitor -180 mmfd. Capacitor -220 mmfd. Capacitor -226 mmfd. Capac

33、itor -630 mmfd. Capacitor -2,200 mmfd. Capacitor-.0035 mid. Capacitor-.005 mfd. . Capacitor-.O1 mfd. Capacitor-.02 mfd. . Capacitor-.05 mfd. Capacitor-0.1mfd. Cell-Bias cell Coil-Antenna coil Coil-Loop primary coil Coil-Oscillator coil Coil-Push button oscillator coil-high frequency Coil-Push button

34、 oscillator coil-low frequency Coil-R.F. coil Condensers -gang variable tuning condenser Control-Volume control and power switch Cord-Pointer cord (approx. 60 -in. overall length) Core-Adjustable core and stud for oscillator coil Core-Adjustable core and stud for push button oscillator coils Cup-Coi

35、l mounting cup and bushing Drum-Condenser drive drum Frame-Dial frame complete-less dial Holder-Bias cell holder 35798 38356 5040 31373 13220 34765 35885 30694 14075 30436 35875 12266 30650 30651 30648 30649 30992 35797 31364 35787 31251 31418 12007 38362 38384 38369 35636 35790 35588 35959 35969 38

36、817 38373 5039 38374 38376 38375 37334 38378 38377 35814 11765 34317 33774 30900 34053 Indicator-Station selector indicator Loop-Antenna loop complete-less supports Plug -4 -contact female plug for speaker cable Pulley-Drive cord pulley Resistor -56 ohms, * watt Resistor -100 ohms, * watt Resistor -

37、470 ohms, 2 watt Resistor -3,900 ohms, * watt Resistor -8,200 ohms, watt Resistor -12,000 ohms, # watt Resistor -12,000 ohms, 3 watt Resistor -39,000 ohms, # watt Resistor -56,000 ohms, * watt Resistor -270,000 ohms, # watt Resistor -470,000 ohms, * watt Resistor -2.2 meg., # watt Resistor -10 meg.,

38、 * watt Shaft-Tuning knob shaft Socket-Dial lamp socket Socket-Phono input socket Socket-Tube socket Spring-Pointer cord spring Spring-Retaining spring for oscillator coil core and stud Switch-Range switch Switch-Selector switch Switch-Tone switch Transformer-First I.F. transformer Transformer-Secon

39、d I.F. transformer Transformer-Power transformer -105-120 volts, 25 cycle Transformer-Power transformer -105-120 volts, 50-60 cycle-less shields Washer-C washer for tuning knob shaft SPEAKER ASSEMBLIES (92196-3) Coil-Field coil -1,060 ohms Cone-Cone complete with voice coil Plug -4 -prong male speak

40、er plug Transformer-Output. transformer MISCELLANEOUS ASSEMBLIES Bezel-Push button bezel Button-Push button Clip-Dial clip Decalcomania-Control panel decal-Pkg. 5. Dial-Class dial scale Knob-Control knob Lamp-Dial lamp Marker-Station selector marker Mounting-Speaker mounting hardware Spring-Retuning spring for control knobs Spring-Retaining spring for push button