RCA-Victor-Co-Inc-RC-613A 电路原理图.pdf

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1、MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS U 10+5 O H K +5 to on i d H O o c H O t- 05 d ctf d O & 5 S o to ! 5 S 4, 3 * *1 sg igsrj RjC if? ”1 |! o 5 * 5 * !-+ a fc, jsS3a H .2 ( 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS nr -T FM Alignment rca Victor MODEL 710V2 A

2、M-FM Radio-Phonograph Combination Chassis No. RC-613A FREQUENCY RANGE5 Standard Broadcast (BC) .c Frequency Modulation (FM) .cVuC Intermediate Frequency (AM) .“5kc- Intermediate Frequency (FM) .10.7 me. Alignment Indicators: An RCA VoltOhmyst or equivalent meter is necessary for measur ing developed

3、 d-c voltage during FM alignment. Connections are specified in the alignment tabulation below. An output meter is also necessary to indicate minimum audio output during alignment. Connect the output meter across the speaker voice coil. The RCA VoltOhmyst can also be ued as an AM alignment indicator,

4、 either to measure audio output or to measure a-v-c voltage. When audio output is being measured the volume control should be turned to maximum. Signal Generator: For all alignment operations, except as stated in FM alignment, connect the low side of the signal generator to the receiver chassis. The

5、 output should be adjusted to provide accurate resonance indica tion at all times. If output measurement is used for AM alignment the output of the signal generator should be kept as low as possible to avoid a-v-c action. Critical Lead Dress 1. Dress capacitor C5 near chassis base. 2 Dress lead from

6、 pin 5, V-l, to terminal C, of transformer Tl, as near bottom of FM shelf as possible. 8. The lead from capacitor C24 to the high side of the volume control must be dressed next to chassis along front apron. 4. Dress resistors R32 & R83 near chassis base. 5. Dress all A.C. leads away from volume con

7、trol. 6. Solder FM antenna coil primary leads to terminal board with as short a lead length as is practical. 7. Make all FM leads as short as possible. 8 The lead from pin 2. V-3. to chassis ground must be dressed as close to base and as near to the back apron as possible. This lead provides degener

8、ation for the IF stage and neither its length nor the point at which it is grounded.to the chassis should be changed. 9. Dress all leads away from the 8800 ohm resistors R34 and R36. RANGE SWITCH IN FM POSITION-VOLUME CONT. MAXIMUM T3 e Eh lQ.7 MC. C2 FM. OSC. 106 MX. mrnm osc./ttnAnt. I Tie EM. 90M

9、C/LVrA90*U C4 lOJMcJ EM.W fnUTW Mj 1 T2 *AJL C1EM.rriC3F.Mrrri 5KC.J 0- AM S. V- I I osc |j I ANT TOP VIEW OF CHASSIS The FM i-f alignment may be checked by means of an FM sweep generator and cathode* ray oscilloscope. Connect the output from the sweep generator, which is set to 10.7 me., to the FM

10、1st Det.- Osc. grid (6BE6 Pin No. 7) low side to chassis. Disconnect the 5 mfd. capacitor C84 from the Ratio Detector circuit. Connect the high side of- the oscilloscope to the junction of R27 and R28. low side to chassis. Adjust the sweep generator and oscillo scope to obtain the response curve. Th

11、e Ratio Detector characteristic may be viewed by connecting the osc Bioscope across the volume control R22, Capacitor C84 should he re-connected before checking the Ratio Detector characteristic. 110 Turn radio dial to Adjustment for peak output Connect the d-c probe of o VoltOhmyst to the negative

12、lead of the 5 mfd. capacitor C34 and the common lead to chassis. Turn gang condenser to max. capacity (fully meshed). High-side to Pin 1 of drivei tube 6AU6 in series with .01 mfd. low side to chassis High side to I one FM ant. I term, in ! series with : .01 mfd. Low side lo the other FM ant. term.

13、10.7 me. modulated 30% 400 cycles AM (Approx. .1 volt) 10.7 me. 30% modu lation, 400 cycles AM. Adjust to provide 2 to 3 volts indi cation on VoltOhmyst during alignment. Max. ca pacity (fully meshed) T5 top core for max. d-c voltage across C34. T5 bottom core for min. audio output fUsing alte*- nat

14、e loading: T3 bottom core (sec.) T3 top core (pri) Tl bottom core (sec.) Tl top core (pri.) High side to one FM ant. term, in series with 4 a 120 ohm _ . C2 osc. resistor. 106 mc 104 mc C4 ant. Low side to the other FM ant. _ term in_ series with , 5 a 120 ohm 90 mc 90 mc JJ resistor. 12 aftt* 6 Rep

15、eat Steps 4 and 5 until further adjustment does nol improve calibration. fAlternate loading involves the use of a 680 ohm resistor to load the plate winding while the grid winding of the SAME TRANS FORMER is being peaked. Then the grid winding is loaded with the resistoT while the plate winding is p

16、eaked. Only one winding is loaded at any one time. Remove the 680 ohm resistor after T8 and Tl have been aligned. AM Alignment (Correct alignment of the 455 kc. IF requires that the 10.7 mc. IF be aligned previously) RANGE SWITCH IN BC POSITION Connect high side Sig. gen. Turn radio Adjust for peak

17、output of sig. gen. output dial to to |T4 tep core (sec.) AM conver- |T4 bottom ler grid Quiet point core (pri.) 6BE6 V-2 in series 455 kc at low freq. end. |T2 bottom with .01 core (sec.) mfd. fT2 top core (pri.) A termi- C12 osc. nal of ter- 1400 kc 1400 kc C 7 ant. minal board at (loop) rear of c

18、hassis ia series with 200 mmf. (link open) 600 kc 600 kc 16 osc. (Rock gang) Repeat Step 3. After chassis and loop have been installed in cabinet, adjust 6 C7 for max. output on a weak station near 1400 kc. t Align T4 and T2 by means of alternate loading as explained under FM alignment. Use a 47,000 ohm resistor instead of a b80 ohm resistor. Oscilator frequency is above signal frequency on both AM and FM. HOtMU ass tnmt err iouo rowis-voLuui front panel controls 收音机爱 好者资料库 RadioFans.CN