RCA-Victor-Co-Inc-1R81 电路原理图.pdf

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1、RC-IIOZ UES MANUAL OF 19S2 MOST-OFTEN-NEEDED RADIO DIAGRAMS A RCA Victor Model 1R81 Chassis Nos. RC-1102, RC-1102A, RC-1102B, RC-1102C Continued on the _s| next three pages. n o e H 03 P + + O! O s C m 5 u 0 D (30 0 + tJ CO 03 C D a 0 g c D S H tiO 03 pH H H iH + H a fi- + K P4 CO (0 a a I ioS I. M

2、I ” jSSSnlS s t 52 sSu ! yj 2o) !Ox o 05 I vo,S2d I ffoSs-oo o-OdSos s .s*e s j s i. I JsU u -OB-SS, . c g N-Sti-a S.Scs oi-: o o -JS .A -s eg 0 O” S-o-gS . o tj 2 Q. 2 o 3 o |ag.i|5; 0 3 0 .SS bl|i;i1 t 0SCg 2w OO* JsSj g&2a.-l I o Si *2 sjh i g S f07 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S2 MOST-OFT

3、EN-NEEDED RADIO DIAGRAMS RCA Victor Model 1R81, Chassis RC-1102, etc., continued. 2S|o82 . S sagss=tt -a isf CBo-g 05 wg l3=,-&su u p o 0 a oz “ 0 0 S- “Iv-f -S 5 g|a!S.8& - tt - 5 satCj o.-lSj sipg ipi| y 5 2 5 I-til. ! 2 ST “I il 5 till, jfowri* 2 0J 108 Simplified Schematic Diagram- 收音机爱 好者资料库 Ra

4、dioFans.CN 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S2 MOST-OFTEN-NEEDED RADIO DIAGRAMS FM Alignment RCA Victor Model 1R81 (Continued) Alignment Procedure Alignment Indicators: For measuring the developed d-c voltage across C29 during FM align ment an RCA VoltOhmyst or an ec|utvalent meter should he nsed

5、._ An output meter connected across the voice coil is also needed to indicate minimum audio output during FM Ratio Detector alignment. Oscilloscope Alignment: It is preferable to use a sweep generator and oscilloscope for aligning I.F. and R.F. circuits to obtain a visual observation of curve shape

6、during alignment. With F.M sweep generator connected between FM ant._#3) ter minal and chassis and oscilloscope connected between the junction of R28-r30 and chassis the overall FM response may he observed. There should he a peak to peak separation of not less than 180 kc. with 50,000 mv. input. AM

7、Alignment RANGE SWITCH IN AM POSITION RANGE SWITCH IN FM POSITION VOLUME CONTROL MAXIMUM Steps Connect high side of sig. gen. to Sig. gen. output Turn radio dial to Adjust for peak output 1 Connect the lead of the 2 to chassis. d-c probe of a VoltOhmyst to the negative mfd. capacitor C29 and the com

8、mon lead 2 Pin 1 of V4 6AU6 in series with .01 mfd. 10.7 me. modulated 30% 400 cycles AM T5 top core for max. d-c voltage acreee C29. T5 bottom core for min. audio output.* 3 Pin 1 of V3 6BA6 in series with .01 mfd. Adjust to provide 3 to 4 volts indi cation on VoltOhmyst during alignment. Quiet poi

9、nt at low freq. end. tt T1 top core (sec.). Tl bottom core (pri.). 4 Pin 7 of V2 6X8 in series with tt T2 top core (sec.). T2 bottom core * Two or more points may be “found which lower the audio output. At the correct point the minimum audio output is approached rapidly and is much lower than at any

10、 incorrect point. tt Alternate loading may be necessary to provide accurate observa tion of peaks. Alternate 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 resistor whi

11、le the plate winding is peaked. Only one winding is loaded at any one time. Remove the 680 ohm resistor after T3 and FI have been aligned. Oscillator frequency is above signal frequency on both AM and FM. Extreme care should be used to avoid running the I.F. cores all the way through the winding and

12、 out the other end. Double peaks or serious overcoupling will result. The correct adjustment may be deteijnmed by starting the core all the way out threads extended). The first peak obtained when tuning should be the correct peak. * Note: FM antenna, mixer and oscillator coils are adjustable by incr

13、easing or decreasing the spacing between turns. The location of the tap on the antenna coil is H turn ys turn from the ground end. lf3 ant. term. In series with a 300 ohm resistor. (Remove ant. lead from ifS term.) 106 me. signal Cl-lT ant. C1-4T r.f. 90 me. signal Ll ant.* L2 r.f* Repeat Steps 5, 6

14、 and 7 tfhtil further adjustment does net improve ealibration. Steps Connect high side of sig. gen. to Si*. K.n. output Turn radio dial to Adjust for peak output D Pin 1 of V3 6BA6 in series with .01 mfd. 455 kc. Quiet point at low freq. end. T4 bottom core (pri.). T4 top core (sec.). B Pin 7 of V2

15、6X8 in series with .01 mfd. T2 top core (sec.). T2 bottom core (pri.). 3 No. 1 terminal on ant. input strip 1620 kc. High freq. end of dial (min. cap.) C1-5T 4 1400 kc. 1400 kc. signal C1-2T ant. C1-3T r.f. 5 Shunt a 10,000 ohm resistor across the r.f. section of the gang. 6 600 kc. 600 kc. signal L6 osc.* (Reck gang.) 7 Remove the lOiOOO ohm resistor and peak L4 r.f.* 8 Repeat 3, 4, 5, 6 and 7 * The correct adjustment of the OSC. L6) core is that peak ob tained with core fartherest away from the coil mounting clips. R.F. (L4) core should be set to the peak obtained (2 peaks are seldom