Capehart-461P-462-P12-Sams-87-2电路原理图.pdf

PHOTOFACT* Folder CAPEHART MODELS 461-P, 462-P12 CHANNEL SELECTOR TINE TUNING BRIGHTNESS CONTRAST VERT. HORIZ. HOLD HEIGHT VERT. LIN. VOLUME TONE OFF-ON-SW CAPEHART MODEL 461-P TRADE NAME Capehart Model 461-P, 462-P12 (Ch. A13, C-255, C-263, C-265, C-266, C-267, C-271.U-12, U-12-A) MANUFACTURER Farnsworth Tel. and Radio Corp., Fort Wayne (1), Indiana TYPE SET Television Receiver TUBES Thirty Seven POWER SUPPLY 110-120 Volts AC-60 Cycle TUNING RANGE-Channels 2 thru 13 RATING 3.8 Amp. at 117 Volts AC Alignment Instructions 8,9 Disassembly Instructions 10 Horizontal Sweep Circuit Adjustments 10 Parts List and Description 17,18,19, 20 Photographs Capacitor Identification 15, 22 Chassis-Top View 3 High Voltage Supply 7 Power Supply 6 RF Tuner (No. 13872) 14 INDEX Photographs (continued) RF Tuner (No. 13900) Resistor Identification Trans., Inductor and Alignment Identification. Schematic (Main) Schematic (Audio) Schematic (High Voltage Supply) Schematic (Tuner No. 13900) Tube Placement Chart Voltage and Resistance Measurements . 23 . 16 21 . 4,13 . 2 . 11 .11 .24 . 5 . . 12 o o m O- m 2 K HOWARD W. SAMS NAL GENERATOR AND VTVM REMARKS Check for response curve similar to Fig 1 with markers as shown. If necessary slightly retouch A5, A6, A8 and A9 for optimum response. Do not change A? or traps Al thru A4. Adjust for maximum deflection. Adjust for zero reading. A positive and negative readiigwill be obtained on either side of the correct setting. A12.A13, Adjust for maximum deflection. A14.A15 IERATOR AND OSCILLOSCOPE 10 * sawtooth voltage in scope for horizontal deflection. CONNECT SCOPE Amp. to Point )w side to is. Amp. to Point iw side to A12, A13 A14.A15 All, AID Adjust for maximum amplitude and symmetry as per Fig 2. Adjust All so 21. 25MC occurs at center of crossover lines as per Fig 3. Adjust A10 for maximum amplitude and straightness of crossover lines. IER NO. 13872) ;e. This aligns the holes in the drive disc with the adjustment screws. npedance, usually 50 ohms. iment. A16,A17 A19 A20 A24,A25 A27 A28 REMARKS Adjust for zero reading. A positive and negative reading will be obtained on either side of the correct setting. Keep slug pairs at approximately the same relative position. Adjust for zero reading. A positive and negative reading will be obtained on either side of the correct setting. Adjust for zero reading. A positive and negative reading will be obtained on either side of the correct setting. Keep slug pairs at approximately the same relative position. Adjust for zero reading. A positive and negative reading will be obtained on either side of the correct setting. ALIGNMENT INS FIG. I FIG. 2 RF AND MIXER AUGt The RF and mixer lines in this tuner are normally very stable. A alignment. Set the contrast control to read -1 1/2 volts on VTVM connected be Connect a . 001MFD capacitor from the grid (pin 1) of the first vide Terminate the sweep generator lead with its characteristic imped; DUMMY ANTENNA Two 120O carbon res. SWEEP GENERATOR COUPLING Across antenna termin- als with 120O in each lead. SWEEP GENERATOR FREQUENCY 213MC (10MC Sweep) 207MC (10MC SWP) 201MC (10MC SWP) 195MC (10MC SWP) 189MC 50MC SWP1 183MC (10MC SWP) 177MC (10MC SWP) 85MC (10MC SWP) 79MC (10MC SWP) 69MC (10MC SWP) 63MC (10MC SWP) 57MC (10MC SWP) MARKER GENERATOR FREQUENCY 211. 25MC 215. 75MC 205. 25MC 209.75MC 199.25MC 203. 7 SMC 193.25MC 197.75MC 187.25MC 191. 75MC 181. 25MC 185. 75MC 175.25MC 179.75MC 83.25MC 87.75MC 77.25MC 81. 75MC 67.25MC 71. 75MC 61. 25MC 65. 75MC 55. 25MC 59.75MC CHf 13 12 11 10 9 8 7 6 5 4 3 2 WAVE TRAP ADJUS Wave traps A38 and A39 are used for specific types of interferenc to the channel having the interference, set fine tuning control until int picture and sound, keeping the cores at approximately the same rela FIG. 3 FIG.4 CONNECT TO SET WITH SHORTEST POSSIBLE LEAD FIG. 5 RF AND OSCILLATE Replace the local oscillator tube (V2). Set the fine tuning- control to the mid-position of its range. Construct a detector probe as shown in figure 5, connect the detec leads. The trap on the converter output transformer must be properly all The coupling adjustment rings (A305 and A306) are pre-set at the f DUMMY ANTENNA Two 120O carbon res. SWEEP GENERATOR COUPLING Across antenna ter- minals with 120 in each lead. SWEEP GENERATOR FREQUENCY 213MC (10MC SWP) 207MC (10MC SWP) 201MC (10MC SWPj 195MC (10MC SWP) 189MC (10MC SWP) 183MC (10MC SWP) 177MC (10MC SWP) 85MC (10MC SWP) 79MC (10MC SWP) 69MC (10MC SWP) 63MC (10MC SWP) 57MC (10MC SWP) MARKER GENERATOR FREQUENCY 211. 25MC 215.75MC 205.25MC 209.75MC 199.25MC 203.75MC 193.25MC 197.75MC 187.25MC 191. 75MC 181. 25MC 185.75MC 175.25MC 179.75MC 83.25MC 87.75MC 77.25MC 81. 75MC 67.25MC 71. 75MC 61. 25MC 65.75MC 55. 25MC 59.75MC CHA 13 12 11 10 9 8 7 6 5 4 3 WAVE TRAP AT Wave traps A313 and ASH are used for specific types of inte receiver tuned to the channel having the interference, set the for minimum interference in both the sound and picture, ke other for minimum interference. FIG. 6 RadioFans.CN j 25.75MC ,50% VIDEO IARKER ALIGNMENT INSTRUCTIONS CCONTJ RF AND MIXER ALIGNMENT (TUNER NO. 13872) The RF and mixer lines in this tuner are normally very stable. Alignment should not be attempted unless they are definitely known to be out of alignment. Set the contrast control to read -1 1/2 volts on VTVM connected between the junction of R67 and R68, and chassis. Connect a . 001MFD capacitor from the grid (pin 1) of the first video IF amplifier (V4) to chassis, using the shortest possible leads. Terminate the sweep generator lead with its characteristic impedance, usually 50 ohms. DUMMY ANTENNA Two IZOSt carbon res. SWEEP GENERATOR COUPLING Across antenna termin- als with 120JJ in each lead. SWEEP GENERATOR FREQUENCY 213MC (iOMC Sweep) 207MC (IOMC SWP) 201MC (IOMC SWP) 195MC (IOMC SWP) 189MC (IOMC SWP) 183MC (IOMC SWP) 177MC (IOMC SWP) 85MC (IOMC EWP) 79MC (IOMC SWP) 69MC (IOMC SWP) 63MC (IOMC SWP) 57MC (IOMC SWP) MARKER GENERATOR FREQUENCY 211.25MC 215.75MC 205. 25MC 209.75MC 199.25MC 203. 7 SMC 193. 2 SMC 197.75MC 187.25MC 191. 75MC 181. 25MC 185.75MC 175.25MC 179.75MC 83.25MC 87.75MC 77.25MC 81.75MC 67.25MC 71. 75MC 61. 25MC 65. 75MC 55. 25MC 59.75MC CHANNEL 13 12 11 10 9 8 7 6 5 4 3 2 CONNECT SCOPE Vert. Amp. thru 10KJ2 to Point Low side to chassis. ADJUST A30, A31, A32, A33 A34.A35, A36.A37 REMARKS Adjust for response curve similar to Fig 4 with markers above 70%. Check for response curve similar to Fig 4. If markers are below 70% on any channel, make slight adjustment of A30, A31, A32 and A33 with channel selector set for that channel. Recheck all high band channels to see that they have not been seriously effected. Adjust for response curve similar to Fig 4 with markers above 70%. Check for response curve similar to Fig 4. If markers are below 70% on any channel, make slight adjustment of A34, A35, and A36, A37 with channel selector set for that channel. Recheck all low band channels to see that they have not been seriously effected. WAVE TRAP ADJUSTMENT (TUNER NO. 13872) Wave traps A38 and A39 are used for specific types of interference and their alignment will depend upon the type encountered. With the receiver tuned to the channel having the interference, set fine tuning control until interference is at maximum. Adjust A38 and A39 for minimum interference in the picture and sound, keeping the cores at approximately the same relative position. Turn one core 1/2 turn, adjust the other for minimum interference. RF AND OSCILLATOR ALIGNMENT (TUNER NO. 13900) Replace the local oscillator tube (V2). Set the fine tuning- control to the mid-position of its range. Construct a detector probe as shown in figure 5, connect the detector probe to pin 1 (Grid) of the first video IF amp. (V4), using the shortest possible leads. The trap on the converter output transformer must be properly aligned before attempting RF and oscillator alignment. The coupling adjustment rings (A305 and A306) are pre-set at the factory and sealed and should not normally require adjustment in the field. DUMMY ANTENNA Two 120S! carbon res. SWEEP GENERATOR COUPLING Across antenna ter- minals with 120S2 in each lead. SWEEP GENERATOR FREQUENCY 213MC (IOMC SWP) 207MC (IOMC SWP) 201MC (IOMC SWP) 195MC (IOMC SWP) 189MC (IOMC SWP) 183MC (IOMC SWP) 177MC (IOMC SWP) 85MC (IOMC SWP) 79 MC (IOMC SWP) 69 MC (IOMC SWP) 63MC (IOMC SWP) 57MC (10MC SWP) MARKER GENERATOR FREQUENCY 211. 25MC 215.75MC 205. 25MC 209.75MC 199.25MC 203.75MC 193. 25MC 197.75MC 187.25MC 191.75MC 181. 25MC 185.75MC 175.25MC 179.75MC 83.25MC 87.75MC 77.25MC 81. 75MC 67.25MC 71. 75MC 61. 25MC 65. 75MC 55. 25MC 59.75MC CHANNEL 13 12 11 10 9 8 7 6 5 4 3 2 CONNECT SCOPE Vert. Amp. thru detector probe to point Low side to chassis. (See note above). ADJUST A311, A301, A302, A303, A304 A312, A307, A308, A309, A310 REMARKS Adjust A311 to place sound marker at bottom of dip as per Fig 6. The video marker should be above 80%. If necessary adjust A301, A302, A303 and A304 to place video marker as shown in Fig 5. Keep trimmer pairs at approximately the same relative position. Check all high band channels to see that the sound marked can be tuned to the bottom of the dip well within the range of the fine tuning control. If not compromise adjustment of A311 may be made to obtain optimum results. If the video marker falls below 70% on any channel, make slight adjustment of A301, A302, A303 and A304 with selector switch set for that channel. Recheck all high band channels to see that they have not been seriously effected. Adjust A312 to place sound marker at bottom of dip as per Fig 5. The video marker should be at 80%. If necessary adjust A307, A308, A309 and A310 to place video marker as shown. Keep trimmer pairs at approximately the same relative position. Check all low band channels to see that the sound marker can be tuned to the bottom of the dip well within the range of the fine :uning control. If not compromise adjustment of A312 may be made to obtain optimum results. If the video marker falls below 70% on any channel, make slight adjustment of A307, A308, A309 and A310 with channel selector set for that channel. Recheck all .ow band channels to see that they have not been seriously effected. WAVE TRAP ADJUSTMENT (TUNER NO. 13900) Wave traps A313 and ASM are used for specific types of interference and their adjustment will depend upon the type encountered. With the receiver tuned to the channel having the interference, set the fine tuning control until the interference is at maximum. Adjust A313 and ASH for minimum interference in both the sound and picture, keeping the cores in the same relative position. Turn one core z turn, adjust the other for minimum interference. f D V KFR PAGE 9 RadioFans.CN HORIZONTAL SWEEP CIRCUIT ADJUSTMENTS HORIZONTAL OSCILLATOR ALIGNMENT CHECK: After turning the horizontal hold control to the maximum counter clockwise position, the picture should remain in horizontal sync. Remove the pic- ture momentarily by turning the contrast control fully counter-clockwise and then return it to the normal operating position. This should pull the picture back into synchronization. Now turn the horizontal hold control fully clockwise. The picture should remain in sync. Momentarily remove the signal and again the picture should pull into sync, if receiver is functioning properly. If the receiver functions properly under these checks it is not necessary to align the horizontal oscillator circuit. However, if the picture is not normal or stable the horizontal oscillator must be aligned. SLIGHT RETOUCH ALIGNMENT: If the receiver failed in the above check to hold sync at either extreme of the hold control or after momentary removal of the signal, it may be possible to align the horizontal oscillator by making slight adjustments. If this fails it will be necessary to completely re-align the horizontal oscillator circuit. Tune in a TV station and adjust tuning for best sound quality. Sync the picture and adjust the contrast control to slightly less than normal position. Turn the horizontal hold control to the point where the horizontal oscillator .fails to hold or pull in. Remove signal. Turn Bl frequency adjustment (located at rear of chassis) until oscillator pulls into sync. Now check the pull-in and hold for the other extreme of the horizontal hold control. COMPLETE ALIGNMENT: Tune in a TV station for the best SOUND quality. Adjust VERTICAL hold control to vertically sync the picture and adjust the contrast control to slightly less than normal. Turn Bl frequency adjustment until picture syncs horizontally. If blanking bar is present on picture adjust B2 phasing adjust screw) until blanking bar moves to the right and off the raster. If ripples occur in the raster turn B2 in a clockwise direction until the unstable condi- Jion is removed. The length of this adjustment screw in its correct position is usually about 1/2 inch beyond the bushing. Turn horizontal hold control fully counter-clockwise and adjust Bl until picture fails to sync. Now slowly turn Bl to the point where the picture syncs again. Readjust B2 so that the left side of picture is close to the left side of the raster but does not fold over. Turn horizontal hold fully clockwise. Right side of picture should be close to right side of raster but does not fold over. If picture does fold over, readjust B2. When signal is restored after momentary removal of the signal, the picture should fall into sync. If picture fails to fall into sync, turn Bl counter- clockwise until picture syncs in. Turn horizontal hold fully counter-clockwise. Picture should fall back into sync, after momentary removal of signal. If picture fails to pull in sync after momentary removals of the signal in both extremes of the horizontal hold control, there may not be a sufficient pull-in range, though not necessarily. A pull-in of 3/4 of the hold control range should be satisfactory. Excessive pull-in is objectionable because high control circuit sensitivity gives greater reaction to noise pulses. This may also affect the vertical sync and equalizing pulses which tend to cause a bend in the top portion of the raster. HORIZONTAL LINEARITY ADJUSTMENTS On some models of these sets, the horizontal width and horizontal linearitv adjustments are slugs, on other models the horizontal linearity is a potentiometer. The latter may or may not have a horizontal width adjustment. Turn the horizontal drive control clockwise as far as possible without crowding the right side of the picture. If the set has a width adjustment, adjust it so picture fills the mask horizontally. Adjust the horizontal linearity for best linearity of the right half of the picture, (readjustment of the horizontal drive control may be necessary for proper results). Center the picture with the centering control. DISASSEMBLY INSTRUCTIONS-MODEL 461-P 1. Remove four push-on type control knobs. 2. Remove six screws holding rear cover. Open cover. 3. R