RCA-KCS94-Sams-315-9电路原理图.pdf

PHOTO FACT* Folder RCA VICTOR MODELS 17-PT-6962, U, 17-S-6O22, U, 17-S-6O25, U, 17-S-6O27, U (Ch. KCS94, A) DISASSEMBLY INSTRUCTIONS CHASSIS REMOVAL 1. Remove 1 push-on type control knobs from top panel of cabinet. (Also remove 2 metal screws holding plastic guard.) 2. Remove 5 clip springs from rear cover. Remove rear cover. 3. Remove picture tube socket, ion trap and centering magnet. 4. Disconnect speaker leads. 5. Remove 2 chassis bolts from bottom of cabinet and 2 hex nuts at the top holding chassis in cabinet. 6. Pull chassis part way out and remove HV lead, then remove chassis the rest of the way. SERVICING IN THE FIELD TUNER OSCILLATOR ADJUSTMENTS Touch-up adjustments of the VHF tuner oscillator circuit may be accomplished by removing the channel selector and tine tuning knobs. PICTURE TUBE SAFETY GLASS CLEANING To clean safety glass remove clamp under the bottom edge of the front metal trim and let safety glass slide down and out bottom of cabinet). Use extreme caution when removing safety glass. PICTURE TUBE REMOVAL For picture tube removal it is necessary to remove chassis. (See disassembly instructions). SERVICE ADJUSTMENT LOCATION See tube placement chart on page 11. SPECIAL ADJUSTMENTS AGC Control Adjustment (Used in VHF-UHF Models only) If receiver overloads on a strong signal, adjust the AGC control until picture shows no sign of overloading or un- stable sync. The normal setting of the AGC control is at its mid-range position. HORIZONTAL OSCILLATOR FIELD ADJUSTMENT The horizontal hold control (L54) is located on the control panel of the chassis and is used as a horizontal hold control. If horizontal sync cannot be brought in by adjust- ing the horizontal hold, set it at approximately its mid- range position, and synchronize the picture by adjusting the horizontal waveform slug (Bl). SOUND IF DETECTOR BUZZ ADJUSTMENT To eliminate sound IF detector buzz, adjust the ratio detector secondary (A49) located on top of chassis. FUSES One fuse is used for horizontal sweep circuit protection, (For location see tube placement chart). CENTERING Centering is accomplished mechanically by adjusting two magnetic rings around the neck of the picture tube, located flush against the deflection yoke. Rotate the two rings around the neck of the tube until the picture is properly centered. O o- o O Ji K HOWARD W. SAMS AC voltage measured a t 1,000 ohms unless otherwise stated, per volt. 4. Line voltage maintained at ,F,L. STRING, !$B? rtJOri 5X8 loop 4B07A 1000 2AF4 1000 17AVP -r TO IOOO *T* 470 1 MMF MMF T | MMF RLAMEMT CONNECTIONS USED IN UHF-VHF MODELS operation; no signal applied. PHOTOFACT STANDARD NOTATION SCHEMATIC How.,d W. S.m. * Co, Inc. 1956 RadioFans.CN AFAMP B SUB TAKEN WITH PIN 7 O TUBE (VIOB) SHORTED TO GROUND, AND HEIGHT CONTROL (R4) SET AT CENTER OF ROTATION. SYNC AMP A 6CG7 RadioFans.CN 5 ! ( g WID7H | p , J % 1 BOOST 600V 1 v . . J_ .047 T ?68K 00 NOT MEASURED T,F 3 TT 3/IOAMP 0101 T 250V RCA VICTOR MODELS 17-PT-6962, U, 17-S-6O22, U, 17-S-6O25, U, 17-S-6O27, U (Ch. KCS94, A) RadioFans.CN (C98) (C104)(C55) (C103) 97) 99)(ciOO) CHASSIS BOTTOM VIEW-CAPACITOR IDENTIFICATION (V yfr6S3 HD) 0 ZCO9-S-ZI yn SCO9-S-ZL 7n SZO9-S-/L 7n yt969-id-/i siaaow MOIDIA RadioFans.CN RF TUNER-RIGHT SIDE RF TUNER-LEFT SIDE PAGE 4 RadioFans.CN ALIGNMENT INSTRUCTIONS 1. 2. 3. 4. 5. 6 7 8 1 2. 3 4 5 6 ESXStttol+SSSiSZ augment. If not rented, the high voHage lead should be taped securely and kept away from the chassis. VIDEO IF ALIGNMENT USING TUNER KRK32B Connect the ends of a lOOOfi potentiometer across a 7. 5 volt battery capable of withstanding considerable current dram. Connect the negative terminal arm to point , Set potentiometer arm to obtain -3. 5 volts at point . Connect the positive terminal to chassis. Connect the synchronized sweep vo tage from the sweep generator to the horizontal input of the oscilloscope for horizontal deflection. DUMMY ANTENNA 0015MFD Two 130S1 Carbon Resistors SWEEP GENERATOR COUPLING High side to point . Low side to chassis. High side to point . Low side to tuner chassis Across antenna termi- nals with 1,31)12 in each lead. SWEEP GENERATOR FREQUENCY Not used 44MC (10MC Swp) MARKER GENERATOR FREQUENCY 44 . SMC 45. SMC 43.0MC 47.25MC 42. SMC 45.75MC 42 . SMC 45.0MC 45.75MC 41.25MC 42. SMC 45.0MC 45.75MC CHANNEL Any un- used channel 4 4 All VHF channels separately CONNECT SCOPE USE VTVM. DC probe to point . Common to chassis. Vert. Amp. of scope thru detector (Fig.l) to pin 5 (plate) of 1st. Video IF Amp. tube (V3). Low side to chassis. Vert. Amp. to point . Low side to chassis. ADJUST Al A2 A3 A4 A5.A6, A7 A1.A2, A3 A1.A3 A1,A2 REMARKS Attenuate generator output to maintain not more than -3 volts on VTVM. Adjust for maximum deflection. Increase generator output to maintain -3 volts on VTVM. Adjust for MINIMUM deflection. Adjust bias to read -3 . 5 volts at point . Clip a carbon 33012 resistor from pin 2 (grid) of 3rd. video IF amplifier (V5A) to chassis. Connect a 180(2 carbon resistor from plate to screen (pins 5 and 6) of 1st. video IF amplifier tube (V3). Preset A5 (trimmer) to minimum capacity. If a separate signal generator is used for marker couple It loosely to detector as in Fig. 1. Attenuate output of sweep generator to give 0. 5 volts peak to peak on scope. Adjust A6 and A7 for maximum gain with 45.75MC marker at 75% of maximum re- sponse as in Fig. 2. Adjust A5 to place 42. SMC marker at 70% response on curve as in Fig. 2. Disconnect the 180S2 and 330ft resistors. Remove scope and detector from pin 5 of V3 . Attenuate output of sweep generator to obtain 3 to 5 volts peak to peak on scope. If a separate signal generator Is used for a marker, couple it loosely to pin 1 (grid) of 1st. video IF amplifier tube (V3). Retouch Al, A2 and A3 if necessary to obtain response curve similar to Fig. 3. Increase sweep generator output ten times and notice attenuation at 41.25MC. Adjust Aland A3 to set 41. 25MC marker at approximately 30 times down with re- sponse curve as shown in Fig- 3. Slightly readjust Al and A2 to correct any overall tilt while switching from channel to channel as In Fig. 3. Couple marker gener- ator loosely to first video IF Amp. tube grid. Continue alignment with step 13. VIDEO IF ALIGNMENT USING KRK29K/36A TUNE! UNIT Same instructions as under Video IF Alignment Using Tuner KRK32B DUMMY ANTENNA .0015MFI Ceramic Capacitor SWEEP GENERATOR COUPLING High side to point . Low side to tuner chassis. SWEEP GENERATOR FREQUENCY Not used 44MC (10MC Swp) MARKER GENERATOR FREQUENCY 44. SMC 45. SMC 43.0MC 47.25MC 42 . SMC 45.75MC 42. SMC 45.0MC 45.75MC CHANNEL Any un- used channel - 4 4 CONNECT SCOPE USE VTVM. DC probe to point . Common to chassis. Vert. Amp. of scope thru detector (Fig.l) to pin 5 (plate) of 1st. video IF amp. tube (V3) . Low side to chassis. Vert. Amp. to point . Low side to chassis. ADJUST Al A2 A3 A4 A5.A6, A7 A1.A2, A3 REMARKS Attenuate generator output to maintain not more than -3 volts on VTVM. Adjust for maximum deflection. Increase generator output to maintain -3 volts on VTVM. Adjust for MINIMUM deflection. Adjust bias to read -3.5 volts at point . Clip a carbon 330J2 resistor from pin 2 (grid) of 3rd. video IF amp. tube (V5A) to chassis. Connect a 180J2 carbon resistor from plate to screen (pins 5 and 6) of 1st. video IF amp. tube (V3). Preset A5 (trimmer) to minimum capacity. If a separate signal generator is used for marker couple it loosely to detector as in Fig. 1. Attenuate output of sweep gener- ator to give 0 . 5 volts peak to peak on scope. Adjust A6 and A7 for maximum gain with 45.75MC marker at 75% of maximum response as In Fig. 2. Adjust A5 to place 42. SMC marker at 70% response on curve as in Fig. 2. Disconnect the 180S2 and 33012 resistors. Remove scope and detector from pin 5 of V3 . Attenuate output of sweep generator to ob- tain 3 to 5 volts peak to peak on scope. If a separate signal generator is used for a marker, couple it loosely to pin 1 (grid) of 1st. video IF amp. tube (V3). Retouch Al, A2 and A3 if necessary to obtain re- sponse curve similar to Fig. 3. SET 315 FOLDER 9 PAGE 5 RadioFans.CN VIDEO IF ALIGNMENT USING KRK29K/36A TUNER UNIT (CONT.) ALIGNMENT INST DUMMY ANTENNA .0015MFD Two 13 00 Carbon Resistors 10000S2 Carbon Resistor in series with .0015MFD ceramic capacitor TWO 13 on Carbon Resistors 300n pad (Fig. 5) SWEEP GENERATOR COUPLING High side to point . Low side to chassis. Across VHF antenna ter- minals with 130S2 In each ead. High side to front terminal of IN82 cry- stal holder. Low side to tuner case. Use very short leads. Across antenna (VHF) terminals with 1300 in each lead. Across UHF antenna terminals thru 300E2 pad (Fig. 5). SWEEP GENERATOR FREQUENCY 44 MC (10MC Swp) 797MC (10 MC Swp) 44 MC (10MC Swp) See freq. chart of all UHF channels MARKER GENERATOR FREQUENCY 41.25MC 42 . SMC 45.0MC 45.75MC 45.75MC 42.5MC 42.5MC 45.0MC 45.75MC 46. SMC CHANNEL 4 All VHF channels separately Between channels 68 and 69 Check all VHF channels Check aUUHF channels CONNECT SCOPE Vert. Amp. to point . Low side to chassis. Vert. Amp. thru detector Fig. 1) to junction of 220S2 and .0015MFD (see remarks). Low side to chassis. Vert. Amp. thru detector (Fig. 1) to point . Low side to chassis. Vert. Amp. to point . Low side to chassis. ADJUST A1.A3 A1.A2 A8,A9 A10, All A1,A2 A10.AU REMARKS Increase sweep generator output ten times and notice attenuation at 41.25MC. Adjust Al and A3 to set 41.25MC marker at approximately 30 times down with response curve as shown in Fig. 3. SLIGHTLY readjust Al and A2 to correct any overall tilt while switching from VHF channel to VHF channel (Fig. 3). Set tuner to UHF position. Connect a 220fi n series with a .0015MFD capacitor (ceramic) between pin 1 (plate) of 4BQ7A ar.d chassis with the capacitor end connected to pin 1 of 4BQ7A and resistor end to chassis If VHF generator is used as a marker, couple it loosely to detector (Fig-1). Connect a second bias supply to point . Positive side to tuner case. Adjust for -3 volts at point . Attenuate sweep generator for 0. 5 volts peak to peak on scope. Adjust A8 and A9 for maximum gain as in Fig. 4. Tuner in UHF position- Loosely couple marker generator to detector (Ftg.l). If necessary, adjust A10 and AH to place 45.75MC marker at peak of curve with MINIMUM tilt. Remove 220J2 resistor and .0015MFD capacitor from pin 1 of 4BQ7A tube. Remove detector and scope from point . Couple marker generator loosely to first video IF amplifier grid. Check for response curve similar to Fig. 3 on all VHF channels. SLIGHTLY retouch Al and A2 if necessary to correct for any overall tilt as in step 8. Couple marker generator loosely to first video IF amplifier grid. Check for response curve similar to Fig. 3 on ail UHF channels. If necessary, SLIGHTLY retouch A10 and All to correct for any overall tilt. Do not retouch Al, A2, A3, A6, A7, A8 or A9 in this step. Remove all test equipment. Disconnect both bias supplies. KRK32B, KRK29K/36A ANTENNA WATCHING UNIT ALIGNMENT The antenna matching unit has been properly aligned at the factory. The RF unit is aligned with a particular antenna matching unit in place. If a new antenna unit is installed, the RF unit should be realigned. Alignment should not be attempted without the proper alignment facilities. The FM trap adjustment (A46) which is located on the antenna matching unit may be adjusted without seriously affecting the RJT alignment. Disconnect the lead from the FM trap (L7) to the channel selector switch. Use a short jumper to connect point <1y on the matching unit through a . 001MFD capacitor to pin (grid) of second video IF amplifier tube (V4). Remove the first video IF amplifier tube (V3) from its socket. Cover o the matching unit must be in place during alignment. Connect the negative terminal of potentiometer arm of bias supply to point 0*0 . Positive termina to chassis. Set the potentiometer arm to obtain -5 volts at point on VTVM. Note: Adjustments A!2 thru A15 are adjusted by expanding or compressing coil turns, except in antenna matching units in which C6, C7 and C8 are variable capacitors. C6 would be adjustment A13. C7 would be adjustment for A14 and A15. C8 would be adjustment A12. Connect the synchronized sweep vo tage from the sweep generator to the horizontal input of the oscilloscope for horizontal deflection, The sweep generator output lead should be terminated with its characteristic impedance, usually 50 ohms. DUMMY ANTENNA Two 130r Carbon Resistor 3 00 ft Pad (Fig. 5) SWEEP GENERATOR COUPLING Across antenna termi- nals with 13CM2 in each lead. Across antenna termi- nals thru 300S2 pad (Fig. 5). SWEEP GENERATOR FREQUENCY Not used 50 MC (20MC Swp) MARKER GENERATOR FREQUENCY 45.75MC (4 00 .Mod) 41.25MC (4000-Mod) 50 MC 52MC 53 MC 60MC CHANNEL Any CONNECT SCOPE Vert. Amp. to point . Low side to chassis. Vert- Amp. thru detector probe (Fig. 1) to point . Low side to chassis. ADJUST A12 A13 A14.A15 REMARKS Set scope gain to maximum and adjust for MINIMUM 400 indication on scope. Remove the .001MFD capacitor from point to pin 1 of V4. Connect a 30012, n resistor from point to chassis. Adjust A14 and A15 to obtain re- sponse curve similar to Fig. 6. Repeat steps 13, 14 and 15 until no further improve- ment is noted. Remove the 300S2 resistor and the detector probe between point and chassis. Replace V3 in its socket. KRK32B TUNER ALIGNMENT An RF unit which is operative and requires only minor touch up adjustments will require no presetting of adjustments. This unit is properly aligned at the factory and under norma use should not require alignment unless components are changed to effect alignment. When complete alignment is necessary make the following pre - adjustments. 1. Turn A6 so that slug is all the way out. 2. Preset A16 all the way out. 3. Set channel 7 thru 13 slugs one turn from tight. 4. Disconnect the link from terminals of converter plate transformer (L36) and shunt the terminals of L36 with a 3 9S2 carbon resistor. Tuner alignment as outlined below requires the use of a heterodyne frequency meter. The limits of oscillator injection voltage are 2 volts minimum and 5. 5 volts max mum measured at point with a VTVM. Connect negative termina of potentiometer arm of one of the bias supplies to point < . Positive side to tuner chassis. Adjust for -3. 5 volts bias at point Connect the synchronized sweep vo tage from the sweep generator to the horizontal input of the oscilloscope for horizontal deflection. The sweep generator output lead should be termi ated with its characteristic impedance, usually 50 ohms. DUMMY ANTENNA Direct SWEEP GENERATOR COUPLING RF input of heterodyne freq. meter to end of insulated wire insertec in hole provided for adjustment of A30. Be careful that the wire does not touch any of the tuned circuits as this may cause oscillator shift. SWEEP GENERATOR FREQUENCY Not used MARKER GENERATOR FREQUENCY Set freq. meter to 227MC CHANNEL 8 CONNECT SCOPE Not used ADJUST A16 REM