Philco-Radio-and-Television-Corp-51-1731 电路原理图.pdf

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1、收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S1 MOST-OFTEN-NEEDED RADIO DIAGRAMS Fhilco Models 51-1751 and 51-1732 Alignment Information (continued) AM ALIGNMENT PROCEDURE Make alignment with loop aerial connected to radio. The AM alignment should be made before the FM alignment. DIAL

2、 POINTER: Calibration and pointer-index measurements are shown in figure 3. With tuning gang fully meshed, set pointer to index mark. OUTPUT METER: Connect across speaker voice-coil ter minals. SIGN AIL GENERATOR CONNECTION TO RADIO Through a .01 -/*/. con denser to mixer grid, pin I, of 7F8/S. Same

3、 as step 2. Sam# as step 2. DIAL SETTING SIGNAL GENERATOR: Connect AM r-f signal generator as indicated in chart. Generator ground lead to chassis. Use modulated output. RADIO CONTROLS: Set volume control to maximum, tone control counterclockwise, and band switch to broadcast posi tion. OUTPUT LEVEL

4、: During alignment, adjust signal-generator output to hold output meter indication below 1.25 volts. ADJUST TRIMMER R A D I O DIAL SETTING SPECIAL INSTRUCTIONS Gang fully meshed. Adjust, in order given, for maximum output. 1600 kc. Adjust for maximum output. 1500 kc. Adjust for maximum output. TC102

5、nd AM i-f pri. TC5- 1st AM i-f sec. TC41st AM i-f pri. C1DAM osc. shunt ClBAM ant. shunt 580 kc. Adjust for maximum output. This TCIAM ant. tuning core shouid not be necessary unless T1 (aerial transformer) has been re placed. RADIATING LOOP: Make up a 6-to-8 turn, 6-inch-diameter loop, using insula

6、ted wire; connect to signal generator leads and place near radio loop aerial FM ALIGNMENT PROCEDURE Make the AM alignment first. RADIO CONTROLS: Set volume control to maximum, tone control counterclockwise, and band switch to FM position. Allow radio and signal generator to warm up for at least 15 m

7、inutes before making alignment. SIGNAL GENERATOR: Use a signal generator capable of delivering a 9.1-mc. FM signal with a deviation of 80 kc., and modulated AM signals of 92 me., 105 me., and 108 me. Philco Model 7008 Precision Visual Alignment Generator ful fills these requirements. NOTE: The signa

8、l generator must be well bonded to radio chassis. SIGNAL GENERATOR j CONNECTION TO RADIO DIAL SETTING Through a .01 /*/. con denser to pin 1 of 6AU8 I-F amplifier.* 9.1 me. rb 80 kc. deviation. .01 -/if. condenser to pin 1 of 6BA6.* 9.1 me. 80 kc. deviation. .01-yu/. condenser to pin I of 7F8/S.* 9.

9、1 me. 80 kc. deviation. Through a 300 ohm dummy aerial to FM aerial socket, Jl. 108 me. Same as step 4. 105 me. Same as step 4. 92 me. OSCILLOSCOPE: Connect to FM Test jack. Model 7008 is suggested. OUTPUT METER: Connect across speaker voice-coil ter minals. R-F COIL NOTE: Check resonance of circuit

10、s containing coils Ll, L2, and L3 by inserting each end of a tuning wand, such as Philco Part No. 45-8885, into coil. If signal strength in creases when powdered-iron end is inserted, compress turns slightly. If signal strength increases when brass end is in serted, spread turns slightly. If signal

11、strength decreases when each end is inserted, no adjustment is necessary. Do no spread or compress turns excessively; only a small change is required at these high frequencies. ADJUST TRIMMER TC9FM det. sec. TC8FM det. pri. TC7FM 2nd i-f sec. TC6FM 2nd i-f pri. TC3FM 1st i-f sec. TC2FM 1st i-f pri.

12、Cl8FM osc. C1CFM r-f Cl AFM aerial L2FM r-f coil LlFM aerial coil | RADIO DIAL SETTING SPECIAL INSTRUCTIONS Gang fully meshed. Adjust TC9 for correct crossover. Adjust TC8 for maximum and equal peaks. Repeat. Gang fully meshed. Adjust, in order given, for maximum and equal peaks. Repeat. Gang fully

13、meshed. Adjust, in order given, for maximum and equal peaks. Repeat. 108 me. Adjust trimmer for maximum reading on output meter. 105 me. Adjust for maximum output while rocking gang. 92 me. Adjust coils, in order given, for proper resonance * CAUTION: Do not overload! When aligning the i-f stages, the curve will be distorted or destroyed if too great a signal is used. To check, attenuate the signal input. If the curve changes in form, rather than merely decreasing in amplitude, the 4 stage is overloaded. 收音机爱 好者资料库 RadioFans.CN