RCA-Victor-Co-Inc-RC-1129A 电路原理图.pdf

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1、83 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19SS MOST-OFTEN-NEEDED RADIO DIAGRAMS RCA Victor Model 6-RF-9, Chassis RC-1129A (Continued) (See also next page) CORE PEAKING Incorrect peaking can seriously affect gain and bandwidth. The correct peak is noted for the various coils and trans formers. 1. The RF t

2、ransformer core screw should be adjusted on the peak position furtherest removed from the coil mounting clip. An incorrect peak may sometimes be obtained with the core screw almost all the way into the clip. 2. The oscillator coil (AM) should be adjusted on the peak obtained with the core coming out

3、 the lug end of the coil. When adjusting from the top of the chassis, this is the peak with the core furtherest into the coil. 3. The position of the FM IF transformer screws should be noted after adjustment. These cores should be peaked with the core part way out of the coil toward the ad justing h

4、ole. It is possible to run the IF cores all the way through the FM windings and obtain a second peak. This will cause serious overcoupling and should be avoided by using a marked adjusting stick. The correct peak is always the first peak obtained when the core is started in from the backed all the w

5、ay out position. VOLTAGE CHART TENSION SPRING RF emp. SCB6 Elements Pin No. AM FM* Phono. Plate 5 195 t28 Screen 6 96 65 Cathode 2 0.4 0.5 . Grid 1 -1.4 -0.2 Plate 9 39 38 . Screen 8 39 39 _ Grid j 7 -2.8 -1.5 Plate 1 3 79 66 _ Grid 2 -.l -2.3 Plate 5 195 187 218 Screen 6 122 100 130 Cathode 7 0.8 0

6、.9 0.9 Grid 1 -1.6 -1.2 Plate 5 200 195 222 Screen 6 65 62 69 Cathode 7 0.55 0.55 0.65 Plate 5 52 50 56 Screen 6 49 47 53 Cathode 7 0.36 0.35 0.4 Grid 1 -0.34 -0.34 -0.3 AF amp. Plate 7 69 69 73 6AV6 Grid 1 -0.8 -0.8 -0.8 Output 6V6GT Plate 3 242 240 243 Screen 4 200 195 222 Cathode 8 11.1 10.7 12.8

7、 Rectifier 5Y3GT FU. 8 257 254 260 TUNING CONTROL The heater voltage of the mixer/oscillator tube (6X8) is approx. 0.4 volt lower than other tubes in the same circuit. This is due to the filament choke coils L7 and L8. Voltages and currents measured with tuning condenser closed and no signal input s

8、hould hold within 20% with rated line voltage. RCA VoItOhmyst used for measuring all voltages. Dial Cord and Drive Assembly FM. ANTENNA SEC TOP PRI. BOT. TONE CONTROL C29A A C29B C29C* (eV6GT VOUTPUT ) (cAve) A.XDEI, A.r. AMP r mww AM OSC. VSSrl- HOONC re 84 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19SS MO

9、ST-OFTEN-NEEDED RADIO DIAGRAMS RCA Victor Model 6-RF-9, Chassis RC-1129A (Continued) ALIGNMENT PROCEDURE Due to the use of separate I.F. transformers, there is little interaction between the 10.7 me. and the 455 kc. adjustments. There is a slight interaction of adjustments on the tuning condenser be

10、tween AM and FM. Final adjustment of AM ant. trimmer should be made with chassis and antenna in cabinet. Alignment Indicators: For measuring the developed d-c voltage across C36 during FM alignment an RCA VoltOhmyst or an equivalent meter should be used. An output meter connected across the voice co

11、il is also needed to indicate minimum audio output during FM Ratio Detector alignment. The RCA VoltOhmyst can also be used to indicate audio output voltage across the voice coil or developed voltage on the AVC bus. Signal Generator: For alignment operations connect the low side of the signal generat

12、or to the receiver chassis. The output of the signal generator should always be controlled to prevent over-load ing or excessive AVC action. Oscilloscope Alignment: It is preferable to use a sweep generator and oscilloscope for aligning I.F. and R.F. circuits to obtain a visual observa tion of curve

13、 shape during alignment. With FM sweep generator connected between FM ant. (#3) terminal and chassis, and oscilloscope connected be tween the junction of R39-C32 and chassis, the overall FM linearity may be observed. With 100% FM modulation there should be a peak-to-peak separation of 150 kc. with 5

14、0,000 microvolts input before noticeable distortion of the sine wave is present. For FM alignment of the ratio detector, connect oscilloscope to junction of 56K resistors as in alignment table, adjusting T6 top and bottom cores for 10.7 me. crossover and balanced peaks. When aligning other FM tuned

15、circuits, connect oscil loscope to TP1. Follow alignment table sequence, adjusting for maximum gain and symmetry. AM Alignment RANGE SWITCH IN AM POSITION TUNtNG COND. DRtVE. DRUM Steps Connect high side ol sig. gen. to Sig. gen. output Turn radio dial to Adjust for peak output Pin 1 ol V3 6BA6 in s

16、eries with .01 mfd. 455 kc. Quiet point at low Ireq. end T4 bottom core (pri.) T4 top core (sec.) n Tap terminal T9 term. 4 in series with .01 mid. T2 top core (sec.) T2 bottom core (pri.) 3 No. 1 terminal on ant. input strip 1620 kc. High freq. ena ol dial (min. cap.) C1E-T 4 1400 kc. 1400 kc. sign

17、al C1B-T ant, C1C-T r.l. 5 Shunt a 10,000 ohm resistor across the r.i. section oi the gang. 6 600 kc. 600 kc. signal T10 osc.* (Rock gang.) 7 Remove the 10,000 ohm resistor and peak T9 r.l.* 8 Repeat 3, 4, 5, 6 and 7 * The correct adjustment of the Osc. (T10) core is that peak obtained with core fur

18、therest away from the coil mounting clips. R.F. (T9) core should be set to the peak obtained (2 peaks are seldom obtainable) with core closest to the mount ing clips. Li - S/fcT. 90 MC. F-M ANT. COIL TIO 600 KC. A.M.OSC.COIL Tt T2 ,STIP- e tST.I.F F.M. A.M. OSC. COIL- (UNDERSIDE of chassis) Tvtoc FM

19、 Coil Locations FM Alignment RANGE SWITCH IN FM POSITION VOLUME CONTROL MAXIMUMTONE CONTROL CENTER Slope Connect high side of sig. gen. to Sig. gen. output Turn radio dial to Adjust for peak output I Pin 1 of V5 6AU6 in series with .01 mid. 10.7 me. modulated 30% * 400 cycles Quiet point at lew freq

20、. end 2 Connect VoltOhmyst across R4t-39K resistor. Adjust Sig. gen. .output to give 1 volt d-c on VoltOhmyst. T6 top core for max. d-c voltage across C36 3 Shunt R41 with two 56K 1% resistors connected in series. Connect VoltOhmyst from center junction ol 56K resistors to junction of R39 and C32. T

21、6 bottom core for 0 volts d-c 4 Pin 1 of V3 6BA6 in series with .01 mfd. 10.7 me. modulated 30% 400 cycles Quiet point at low freq. end VoltOhmyst conn, to fPl. ffT5 top core. T3 top & bottom cores. ffTl top and bottom cores 5 Stator of C1D in series with .01 mfd. FM Ant. terminals 270 ohm resistor

22、in series #3 term. 90 me. 90 me. Remove bottom shield. *Osc. coil L3 106 me. 106 me. signal Replace bottom shield. ClA-T ant., C1D-T r.f. 90 me. 90 me. *L1 ant. L2 r.f. Repeat steps 6, 7, and 8 until further adjustment does not improve calibration. ft Alternate loading may be necessary to provide ac

23、curate observation of peaks. Alternate loading involves the use of a 680 ohm resistor to load the plafe winding while the grid winding of the SAME TRANSFORMER is being peaked. Then the grid winding is loaded with the resistor while the plate winding is peaked. Only one winding is loaded at any one t

24、ime. Remove the 680 ohm resistor after T3 and T1 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 out the other end. * Note: FM antenna, mixer and oscillator coils are ad justable by increasing or decreasing the spacing between turns. The location of the tap on the antenna coil is % turn to % turn from the ground end. 85 收音机爱 好者资料库 RadioFans.CN