LG KF-20P31 Service Manual Download Page 2

Page: 2 / 80

CHASSIS : MV-025A

MODEL : KF-20/21P31

MODEL

CONTENT

SPECIFICATION ................................................1-2

SAFETY INSTRUCTIONS ............................ 1-3

SERVICING PRECAUTIONS ....................... 1-4

DESCRIPTION OF CONTROLS .................. 1-6

SECTION 1

SUMMARY

TVCR

SERVICE MANUAL

Summary of Contents for KF-20P31

Page 1: ...EFORE SERVICING THE CHASSIS READ THE SAFETY PRECAUTIONS IN THIS MANUAL CHASSIS MV 025A MODEL KF 20 21P31 website http biz LGservice com e mail http www LGEservice com techsup html SERVICE MANUAL MODEL KF 20 21P31 LG Electronics inc ...

Page 2: ...CHASSIS MV 025A MODEL KF 20 21P31 MODEL CONTENT SPECIFICATION 1 2 SAFETY INSTRUCTIONS 1 3 SERVICING PRECAUTIONS 1 4 DESCRIPTION OF CONTROLS 1 6 SECTION 1 SUMMARY TVCR SERVICE MANUAL ...

Page 3: ... UHF 21 69 CATV S1 S20 Tuning System Voltage Synthesizer Antenna UHF VHF 75 ohm Sound Output 3Wmax at 50KHz deviation Operating Condition 5 C 35 C less than 80 RH ABBREVIATIONS Used in this book ADJ Adjustment or Adjust AFC Automatic Frequency Control AGC Automatic Gain Control AMP Amplifier CPT Color Picture Tube DEF Deflection DET Detector FBT Flyback Transformer H V High Voltage OSC Oscillator ...

Page 4: ...perform an AC leakage current check on the exposed metallic parts of the cabinet such as antennas terminals etc to be sure the set is safe to operate without damage of electrical shock Leakage Current Cold Check Antenna Cold Check With the instrument AC plug removed from AC source connect an electrical jumper across the two AC plug prongs Place the AC switch in the on positioin connect one lead of...

Page 5: ...es are integrated circuits and some fieldeffect transistors and semicounductor chip components The following techniques should be used to help reduce the incidence of component damage caused by static by static electricity 1 Immediately before handling any semiconductor component or semiconductor equipped assembly drain off any electostatic charge on your body by touching a known earth ground Alte...

Page 6: ...the corresponding lead on the circuit board 4 Securely crimp each connection and solder it 5 Inspect on the circuit board copper side the solder joints of the two original leads If they are not shiny reheat them and if necessary apply additional solder Fuse and Conventional Resistor Removal Replacement 1 Clip each fuse or resistor lead at top of the circuit board hollow stake 2 Securely crimp the ...

Page 7: ... UP DOWN adjusts the volume adjusts menu settings 8 REW REWIND REVIEW rewinds the tape at high speed in the stop mode reviews fast the tape during playback 9 PLAY plays back the tape at normal speed 10 PAUSE STILL stops the tape temporarily during recording displays a still picture during playback 11 STOP stops the tape during playback or recording 12 SLEEP sets the sleep timer 13 TRK AUTO adjust ...

Page 8: ...ote control handset is powered by two AA type batteries Gently pull down the cover of the remote control handset until the battery compartment is exposed Install two batteries as indicated by the polarity symbols and marked inside the compartment Note To avoid damage from possible battery leakage remove the batteries if you do not plan to use the remote control handset for an extended period of ti...

Page 9: ...cts the tape 18 OK option accepts your selection or displays the current mode 19 TAPE IN INDICATOR option illuminates green while a video cassette tape is inserted 20 HEADPHONE SOCKET option connect the headphone plug to this socket Note In some models you might drop the set if you move it only with the handle on the top of the set So you can should support the bottom of the set at the same time F...

Page 10: ...CHASSIS MV 025A MODEL KF 20 21P31 MODEL CONTENT EXPLODED VIEW 2 2 EXPLODED VIEW PARTS LIST 2 3 DISASSEMBLY INSTRUCTIONS 2 4 SECTION 2 DISASSEMBLY PART TVCR SERVICE MANUAL ...

Page 11: ...2 2 EXPLODED VIEW 330 320 315 603 610 601 602 A00 501 520 174 913 510 112 153 170 150 310 943 400 120 ...

Page 12: ...00 3809V00195D 3809V00195D BACK COVER ASSY LOCAL LGEIN PHONE 3809V00195H BACK COVER ASSY CKD 40AF 501 4810V00206B 4810V00206B BRACKET SMPS 4810V00206A BRACKET SMPS 520 6871VDM125N 6871VDM125E PWB ASSY DEFLECTION MAIN2 025A 21 WIDE CKD 601 4810V00195C 4810V00195A BRACKET MAIN P10 P10 P30 33DECK 602 4814V00158B 4814V00158B SHIELD BOTTOM P10 P20 P30 CKD 603 4814V00157F 4814V00157F SHIELD TOP CASE 20 ...

Page 13: ... CPT REMOV AL 1 After removal of VCR chassis and speaker assy remove the CPT board from CPT neck 2 Plase the cabinet with the front down on suitable cushion 3 Remove 4 screws swcuring the CPT to the cabinet 4 Carefully separate CPT from front cabinet PICTURE TUBE HANDLING CAUTION Due to high vacuum and large surface area of picture tube great care is needed when handling the picture tube Always li...

Page 14: ... CONTENT PURITY CONVERGENCE ADJUSTMENT 3 2 ADJUSTMENT INSTRUCTIONS 3 5 BLOCK DIAGRAM 3 9 WIRING DIAGRAM 3 10 TROUBLESHOOTING CHARTS 3 11 PRINTED CIRCUIT BOARDS 3 16 COMPONENT LOCATION GUIDE 3 17 SECTION 3 ELECTRICAL PART TVCR SERVICE MANUAL ...

Page 15: ...mpletely forward 5 Reconnect the internal degaussing coil 6 Position the beam bender locking rings at the 9 o clock position and the other three pairs of tabs 2 4 and 6 pole magnets at the 12 o clock position 7 Perform the following steps in the order given to prepare the receiver for the purity adjustment procedure a Face the receiver in the magnetic north direction b Externally degauss the recei...

Page 16: ...nal degaussing coil 9 Turn on the receiver connect a signal generator to the VHF antenna terminal and apply a crosshatch signal Caution During the convergence adjustment procedure be very careful not to disturb the purity adjustment tabs are accidentally move purity should be confirmed before proceeding with the convergence adjustments Note Make sure the focus is set correctly on this instrument b...

Page 17: ... and blue horizontal lines Fig upper right 17 Temporarily place a rubber wedge at the 5 o clock and 7 o clock positions to hold the horizontal position of the yoke 18 Check the 3 o clock and 9 o clock areas to confirm that the red and blue vertical lines are converged If the lines are not converged slightly offset the horizontal tilt of the yoke move the temporary rubber wedges if necessary to equ...

Page 18: ...HILIPS DIGITAL PATTERN or COLOR BAR PATTERN or CIRCLE PATTERN depend on itmes 3 DECK LINE ADJ VCR DECK CIRCUIT ADJ 3 1 P2 P3 TEMPORARY ADJUSTMENT 3 1 1 Necessary Instruments 1 PAL SP Normal TAPE 2 OSCILLOSCOPE 3 10 1 PROBE two 4 SPECIAL NUT DRIVER P2 P3 FOR ADJUSTMENT 3 1 2 ADJUSTMENT 1 Play the PAL SP NORMAL TAPE 2 Connect the oscilloscope CH 1 to J123 H SW of main PCB 3 Connect the oscilloscope ...

Page 19: ...ote controller 3 3 3 X DISTANCE ADJUSTMENT 1 Turn the X distant adjust groove of the deck right and left to maximize the scope waveform 2 Check that if waveform satisfies with the linearity by pressing TRK Up and Down button 3 Tighten the X distant adjust screw 3 3 4 P2 P3 RF LINEARITY CHECK ADJUSTMENT 1 Adjust p2 p3 so that the the RF envelope waveform of the oscilloscope becomes C in figure 2 2 ...

Page 20: ...ON 4 5 3 ADJUSTMENT Push the SVC key of a transmitter which is possible to control the SVC and adjust the RG and BG varying the VOL in the status of the initial data 32 of the CG in SVC MENU on the screen This chassis adjusts only the high light 4 6 DEFLECTION DATA ADJUSTMENT 4 6 1 INPUT PAL DIGITAL PATTERN EU05CH 4 6 2 PRESS SVC KEY ON THE SERVICE REMOTE CONTROLLER AND SELECT LINE SERVICE2 MODE A...

Page 21: ... GG RG BG PEAK CDL 2nd SIF RF Gain Green Drive Gain Red Drive Gain Blue Drive Gain Peaking Control Cathode Drive Level 2nd SIF 15 32 32 32 17 10 0 15 32 32 32 17 08 0 15 32 32 32 17 12 0 15 32 32 32 17 12 0 CONTENTS 15 21 20 14 Mode 0 1 2 OFF BG DK INternal BPF BG EXTERNAL DK I INTERNAL BPF DK EXTERNAL BG I INTERNAL BPF Funtion Remark Note No 1 2 3 4 FRANCE GERMANY Other EU Except EU FRENCH GERMAN...

Page 22: ...COM SECAM DECODER TA1238N Y C LA71590M AV DY DY DRUM AUDIO AMP OSD IC RGB CRT SPEAKER CVBS AUDIO IN CONTROL CONTROL CONTROL REC PB RF AUDI O OUT VCR CVBS I N VCR AV AUDI O I N AV CVBS IN CVBS OUT RF CVBS I N VCR OUT AV CVBS IN AV AUDIO IN AV AUDIO OUT ...

Page 23: ...3 10 WIRING DIAGRAM TOUCH P805 P805 1 P708 1 P602 P804 P03 P01 P02 P708 P602 P805 P804 P708 P102 P702 P703 P901A SMPS PWB P802 P103 P100 CPT PWB ...

Page 24: ...in 9 of T801 YES NO POWER NO STAND BY Replace the Fuse Check the 6V Line of MAIN 1 BOARD Check if the Fuse is O K YES NO Check Replace DB801 R801 C806 NO Check Replace D806 Q801 R807 ZD801 C814 IC801 NO Check Replace FR851 D852 C856 Q860 Q861 Q862 ZD860 ZD861 R874 Check the pin 11 of P804 LOW NO Check Replace IC857 D856 F852 C875 NO TROUBLE SHOOTING ...

Page 25: ...n 9 of P804 YES NO POWER NO MONITOR ON Go to NO POWER NO ST BY BLOCK Go to NO RASTER BLOCK Check T701 Q781 and go to NO RASTER BLOCK Check the NO POWER NO ST BY BLOCK YES NO Check the pin 10 of P804 HIGH NO Check Replace D851 L851 C860 IC851 Check the pin 10 of P804 HIGH NO ...

Page 26: ...s there about 8V at pin 6 of P805 YES NO RASTER Go to NO POWER BLOCK Go to NO PICTURE BLOCK Is there about 115V at pin 3 of T701 YES NO Check Replace F852 D850 R858 IC853 C863 Check the 8V LINE of VCD BOARD NO Check the H OUT LINE of VCD BOARD Check Replace IC501 of VCD BOARD NO Check Replace Q782 T781 R783 Q781 NO Check Replace T701 5PIN CONNECTOR FR901 FR902 NO ...

Page 27: ... IC701 Does the V A V B signal appear at pin 4 7 of P805 YES NO Check Replace FR702 D703 C703 Check Replace FR701 D702 C704 NO Is there about 185V at pin 1 of P902 YES NO PICTURE Check the CVBS line of VCD Check Replace IC901 Check screen voltage Does the RGB signal appear at pin 3 5 7 of P901A YES NO Check Replace D701 C701 T701 5PIN CONNECTOR NO NO ...

Page 28: ...appear at pin 9 of P805 YES NO SOUND Check Replace FR854 D855 IC601 Check Replace speaker speaker connector Is there about 25V at pin 5 of IC601 YES NO Check the Audio source line of VCD Check the voltage at collector of Q602 Check Replace IC601 external components of IC601 NO NO ...

Page 29: ...3 16 PRINTED CIRCUIT BOARD MAIN ...

Page 30: ...234 F3 J236 G5 J237 D1 J240 F2 J241 F4 J243 E2 J246 F3 J247 E5 J248 F4 J249 F4 J250 G4 J251 G4 J252 F4 J253 G3 J254 E4 J255 G5 J256 F5 J257 E2 J258 F4 J262 G5 J263 G4 J264 G4 J265 F5 J266 G5 J267 G4 J268 E2 J269 F5 J270 F4 J271 G2 J274 G3 J275 F2 J276 F3 J282 D4 J294 F4 J300 F5 J301 E2 J302 A5 J303 A5 J304 G3 J305 D4 J306 C4 J307 D3 J308 C3 J309 D3 J310 C1 J311 A5 J312 B3 J314 B2 J315 B2 J317 E3 J...

Page 31: ...3 18 POWER ...

Page 32: ...3 J810 C3 J811 B5 J812 D3 J813 D1 J814 D1 J815 E3 J816 D5 J817 D3 J818 C4 J819 F3 J820 B2 J821 C2 J822 E4 J823 B4 J824 B5 J825 E2 J826 C2 J827 C4 J829 D2 J830 C2 J831 C2 J832 D1 J834 E3 J835 E5 J836 B3 J837 D4 J838 D5 J839 D4 J840 C3 J841 D4 J842 E3 J843 E5 J844 F4 J847 E3 J848 E3 J849 E3 J850 E3 J851 E3 J854 D5 J857 C5 J858 D4 J860 D1 J863 C5 J864 G3 J865 F3 J868 G2 J873 C3 J875 C2 J877 D1 J879 C...

Page 33: ...3 20 CPT AV 14 AV 20 ...

Page 34: ... KF 20 21P31 MODEL CONTENT Deck Mechanism Disassembly 4 1 Mechanism Adjustment 4 15 Maintenance Inspection Procedure 4 22 Mechanism Troubleshooting Guide 4 26 Exploded Views 4 31 SECTION 4 MECHANISM PART TVCR SERVICE MANUAL ...

Page 35: ... Hole A 2 4 Guide CST 2 Hooks A 2 2 3 4 5 Bracket Side L 1 Screw A 2 2 3 4 6 BracketAssembly Door 1 Screw A 2 2 3 4 5 6 7 ArmAssembly F L Chassis Hole A 2 2 3 4 5 8 LeverAssembly S W Chassis Hole A 2 9 ArmAssembly Cleaner Chassis Embossing A 3 10 Head F E 2 Hooks A 3 11 BaseAssemblyA C Head 1 Screw A 3 12 BrakeAssembly S Chassis Hole A 4 2 3 13 BrakeAssemblyT Chassis Hole A 4 2 3 12 14 ArmAssembly...

Page 36: ...cket Side L 1 Screw A 2 2 3 4 6 BracketAssembly Door 1 Screw A 2 2 3 4 5 6 7 ArmAssembly F L Chassis Hole A 2 2 3 4 5 8 LeverAssembly S W Chassis Hole A 2 9 ArmAssembly Cleaner Chassis Embossing A 3 10 Head F E 2 Hooks A 3 11 BaseAssemblyA C Head 1 Screw A 3 12 BrakeAssembly S Chassis Hole A 4 2 3 13 BrakeAssemblyT Chassis Hole A 4 2 3 12 14 ArmAssemblyTension Chassis Hole A 4 2 3 12 14 15 Reel S ...

Page 37: ...ook the H1 on the back side of the Chassis and separate the Cap FPC 2 Remove three Screws S1 and lift up the Drum Assembly 3 Remove two Screws S2 and Separate the Stator of Drum Motor 4 Remove two Screws S3 and Separate the Rotor of Drum Motor from the Drum Sub Assembly 1 When reassembling Cap FPC two Holes of Drum FPC are inserted to the two Bosses of Holder FPC correctly Refer to Fig B 1 Fig A 1...

Page 38: ...Assembly F L Lever Assembly S W Bracket Side L H5 H3 Groove Guide CST Gear Rack F L Groove For Jog Shuttle Models H4 Bracket Assembly Door S4 S4 Arm F L Holder Assembly CST Lever Stopper R Fig A 2 Fig A 2 1 Fig A 2 2 Fig A 2 6 Fig A 2 7 Fig A 2 5 Fig A 2 3 Fig A 2 4 ...

Page 39: ... above No 1 and disassemble the Guide CST in the direction of the arrow 5 Bracket Side L Fig A 2 4 Bracket Assembly Door Fig A 2 5 1 Remove the Screw S4 and disassemble the Bracket Side L in the front 2 Remove the Screw S4 and disassemble the Bracket Assembly Door in the front 6 Arm Assembly F L Fig A 2 6 1 Push the Arm Assembly F L to the left and lift up it 1 When reassembling confirm that the G...

Page 40: ...and lift up the Arm Assembly Cleaner 9 Head F E Fig A 3 2 1 Unhook the two Hooks H1 on the back side of the Chassis and lift up the Head F E 10 Base Assembly A C Head Fig A 3 3 1 Remove the Screw S5 and lift up the Base Assembly A C Head NOTE DECK MECHANISM DISASSEMBLY H1 Head F E Arm Assembly Cleaner A S5 Base Assembly A C Head For Jog Shuttle Models Fig A 3 Fig A 3 1 Fig A 3 3 Fig A 3 2 Spring L...

Page 41: ... direction and then lift up the Brake Assembly T 1 When reassembling be careful not to change the Spring with above No 11 Refer to Fig B 2 13 Arm Assembly Tension Fig A 4 3 1 Remove the Spring Tension 2 Hold the C part shown above Fig A 4 3 and turn to the clock wise direction and then lift up theArmAssembly Tension 1 When reassembling be careful not to change the Spring with above No 11 12 Refer ...

Page 42: ...bossing of the Chassis in the counterclockwise direc tion and lift up the Base Assembly P4 17 Opener Lid Fig A 5 3 1 Break away the C Part of the Opener Lid from the Embossing of the Chassis in the Clockwise direction and lift up the Opener Lid 18 Arm Assembly T up Fig A 5 4 1 Just lift up the Arm Assembly T UP 1 When reassembling confirm the opener lid is placed on the Hook H1 of the Arm Assembly...

Page 43: ...n 1 When reassembling Confirm the A B parts of Motor Capstan is located to the A B of the Chassis 21 Clutch Assembly D33 K Fig A 6 3 1 Remove the Washer W1 and lift up the Clutch Assembly D33 K 22 Lever F R Fig A 6 4 1 Unhook the H1 shown above Fig A 6 4 and lift up the Lever F R 1 When reassembling move the C part of the Lever F R up and down then confirm if it is returned to original position 23...

Page 44: ...d lift up the Bracket Assembly Jog 25 Guide Rack F L Fig A 7 2 Gear Rack F L Fig A 7 3 1 Remove the Screw S4 and lift up the Guide Rack F L 2 Lift up the Gear Rack F L 26 Brake Assembly Capstan Fig A 7 4 4HD model option 1 Hook the Spring Capstan on the Hook H1 2 Unhook the Hook H2 and lift up the Brake Assembly Capstan Refer to Fig to the right 1 When reassembling confirm that the Hole A of the B...

Page 45: ...t up the Gear Connector 1 When reassembling confirm that the Hole A of the Gear Connector is aligned to the Hole A of the Chassis Fig A 8 3 2 When reassembling confirm that the Hole B of the Gear Cam is aligned to the Hole B of the Chassis Fig A 8 2 3 When reassembling confirm that the C part of the Gear Cam is aligned to the D part of the Gear Drive as shown Fig B 3 28 Bracket Assembly L D Motor ...

Page 46: ... 2 Plate Slider Fig A 9 3 Lever Tension Fig A 9 4 1 Remove the Screw S4 and lift up the Base Tension 2 Lift up the Plate Slider 3 Hold the A Part of the Lever Tension and turn to the counterclockwise direction and then lift up the Lever Tension 1 When reassembling turn the Lever Tension to the clock wise direction in maximum 2 Push the plate slide right side to be guided by the shaft NOTE Fig A 9 ...

Page 47: ...0 4 1 Move the Base Assembly P3 in the direction of the arrow of the Chassis Hole A and push down the Base Assembly P3 2 Move the Base Assembly P2 in the direction of the arrow of the Chassis Hole B and push down the Base Assembly P2 33 Arm Assembly Idler or Arm Assembly Idler Jog Fig A 10 5 1 Unhook the Hook H3 and push down the Arm Assembly Idler Jog 1 Arm Assembly Idler is for Normal Models 2 A...

Page 48: ...00 D006 4 Torque gauge adaptor Parts No D09 R001 5 Post height adjusting driver Parts No DTL 0005 6 Type driver ø 5 2 Alignment tape Parts No NTSC DTN 001 PAL DTN 0002 3 Torque gauge 3 600g Cm ATG 3 Parts No D00 D002 SRK VIDEO CASSETTE TORQUE METER VHT 303 S R K V H T S SRK V HT T 300 250 200 150 50 0 300 250 200 150 50 0 100 ...

Page 49: ... until the Alignment is as below Fig C 2 4 Remove the Screw which fixes the Deck Mechanism and Main Frame and confirm if the Gear Cam is aligned with the Gear Drive as below Fig C 1 A 5 Confirm if the Mode S W on the Main P C Board is aligned as below Fig C 1 B 6 Remount the Deck Mechanism on the Main P C Board and check each operation Mode S W Gear Cam Gear Drive A B L D Motor Assembly Gear Cam H...

Page 50: ...ise until the Alignment is as below Fig C 2 4 Remove the Screw which fixes the Deck Mechanism and Main Frame and confirm if the Gear Cam is aligned with the Gear Drive as below Fig C 1 A 5 Confirm if the Mode S W on the Main P C Board is aligned as below Fig C 1 B 6 Remount the Deck Mechanism on the Main P C Board and check each operation Mode S W Gear Cam Gear Drive A B L D Motor Assembly Gear Ca...

Page 51: ... Adaptor with the Torque Gauge affixed The Torque reading to measure occurs when the Tape abruptly changes direction from Fast Forward of Rewind Mode when quick bracking is applied to both Reels SRK VIDEO CASSETTE TORQUE METER VHT 303 S R K V H T S SRK V HT T 300 250 200 150 50 0 300 250 200 150 50 0 100 Test Equipment Fixture Torque Gauge 600g cm ATG Torque Gauge Adaptor Cassette Torque Meter SRK...

Page 52: ...velope CH 2 NTSC SW 30Hz PAL SW 25Hz Head Switching Output Point RF Envelope Output Point Test Conditions VCR VCP State Play an Alignment Tape Adjustment Point Guide Roller Height Adjustment Screws Fig C 4 2 Fig C 4 3 P3 POST ADJUSTMENT P2 POST ADJUSTMENT Turn the Roller Guide Height Adjustment Screw slightly to flatten the waveform Tracking control at center RF ENVELOPE OUTPUT TEST POINT OSCILLOS...

Page 53: ...Screw Fig C 5 3 A C Head Tape Tape 0 2 0 25mm P4 5 1 Preliminary Adjustment Height and Tilt Adjustment Perform the Preliminary Adjustment when there is no Audio Output Signal with the Alignment Tape 1 Initially adjust the Base Assembly A C Head as shown Fig C 5 1 by using the Height Adjustment Screw B 2 Play a Blank Tape and observe if the Tape passes accu rately over the A C Head without Tape Cur...

Page 54: ...ly adjust the Azimuth Adjustment Screw A and the Tilt Adjustment Screw C for Maximum Output of the 1Khz and 7Khz segments while maintaining the flattest Envelope differential between the two Frequencies Adjustment Procedure 5 3 Precise Adjustment Azimuth adjustment 6 X Value Adjustment Fig C 5 4 1KHZ Oscilloscope Alignment tape SP only Screw Driver Type 5mm CH 1 PB RF Envelope CH 2 NTSC SW 30Hz PA...

Page 55: ... Mechanism Condition Play the blank tape Play an alignment tape Adjustment Points Guide Roller Precise Adjustment Switching Point Tracking Preset X Value Checking Adjustment Procedure Play a blank tape and check for tape curling or creasing around the roller guide If there is a problem then follow the procedure 4 Guide Roller Height and 5 Audio Control A C Head Adjustment RF ENVELOPE OUTPUT TEST P...

Page 56: ... head Dirt on pinch roller If locations marked with o do not operate normally after cleaning check for wear and replace See the EXPLODED VIEWS at the end of this manual as well as the above illustrations See the Greasing Page 4 22 for the sections to be lubricated and greased NOTE o o o o Dirt on video head Dirt on tape transport system Low volume Sound distorted Tape does not run Tape is slack o ...

Page 57: ...ol head Dirt on pinch roller If locations marked with o do not operate normally after clean ing check for wear and replace See the EXPLODED VIEWS at the end of this manual as well as the above illustrations See the Greasing Page 4 22 for the sections to be lubricated and greased NOTE o o o o Dirt on video head Dirt on tape transport system Low volume Sound distorted Tape does not run Tape is slack...

Page 58: ...tch with Isopropyl Alcohol Touch the cleaning patch to the head tip and gently turn the head rotating cylinder right and left Do not move the cleaning patch vertically Make sure that only the buckskin on the cleaning patch comes into contact with the head Otherwise the head may be dam aged Thoroughly dry the head Then run the test tape If lso propyl Alcohol remains on the video head the tape may b...

Page 59: ...ssembly F L U Groove 4 Arm Take up Rubbing Section 5 L D Motor Worm Wheel Part 6 Shaft 7 Arm Assembly F L of Buming Inside Hole 8 Reel S T Shaft G381 Yellow 9 Brake T Groove Guide Rail Gear Assembly Up D Gear Drive Gear Sector Gear Cam Press Cam Part Cam Part Gear Part Stopper Part Bracket Side L Bracket Assembly Door 1 4 5 7 6 3 2 1 Loading Path Inside Top side 2 Shaft 3 Gear Rack F L Moving Sect...

Page 60: ...d sensor Check syscon circuit NO YES YES YES NO NO NO 1 Deck Mechanism A NO NO NO No F R modes Is the present mode F R Mode Is the mode SW assembled correctly refer to Pages 4 14 Is the normal voltage supplied to the Capstan Motor Vcc1 Vcc2 Does terminal voltage Vctl of Capstan Motor supply side more than 4V Check Servo Power Circuits Replace the Capstan Motor Does the Capstan Motor rotate Do the ...

Page 61: ...tions page 4 14 Check spring Pinch Replace Drum Motor Check Servo Syscon Check the Syscon µ COM No cassette loading Insert the cassette Check Cassette Carry Assembly Is there variation for F L S W Output In Tape with REC Tab L H L In Tape without REC Tab L H L H Does the F L S W work normally Does the lever S W work normally Check Syscon Circuit Check Syscon Circuit Replace F L S W YES YES YES YES...

Page 62: ...ensors ok Check Syscon Circuit Check Syscon Circuit Check Servo Syscon Does the Capstan Motor turn Is the terminal voltage of the Drum Motor more than 2 3V Replace the Drum Motor Is the Vcc voltage of the Drum Motor normal Check the clutch and the Idler Assembly YES YES YES YES YES YES YES YES NO NO NO NO NO Is the terminal voltage of Capstan Motor supplied more than 4V Replace the Capstan Motor I...

Page 63: ...Board 5V YES Is there a short circuit between cassette switch and GND on main P C Board Remove the short circuit part or Replace the main P C Board NO Check Mode switch location and syscon circuit Replace F L Switch YES NO YES NO NO Replace F L Switch NO NO Cassette will not eject Does the L D motor rotate in reverse Check L D Motor or Drive IC Replace lever Switch Does the Lever Switch work YES N...

Page 64: ...m Assembly F L Check the power of L D Motor Is the Holder Assembly Cassette assembled correctly Replace the Rear Rack F L Does the Gear Rack F L work Does the Opener Door work Does the Arm Assembly F L work Does the L D Motor work Does the Holder Assembly Cassette move the Arm Assembly F L Replace the Front Loading Mechanism Assembly YES YES YES YES NO NO NO YES NO YES NO YES NO C ...

Page 65: ...4 31 EXPLODED VIEWS 101 426 103 117 104 105 100 110 115 116 112 113 114 032 109 108 426 A22 A23 A21 A24 107 106 1 Front Loading Mechanism Section ...

Page 66: ...03 009 025 026 027 A04 011 031 018 019 021 020 029 003 003 003 004 409 016 O p t i o n a l P a r t s O p t io n a l P a r t s O n l y f o r V C R M o d e l s Only for 4HD Hi Fi Models Only for 4HD Mono Models Only for 2HD Models Optional Parts Only for Jog shuttle Models For Normal Models 2 Moving Mechanism Section 1 ...

Page 67: ... 065 A11 068 069 070 079 426 064 518 052 055 518 517 061 062 062 060 063 519 051 059 A14 058 Optional Parts O p ti o n a l P a r ts Only for 4HD Models O n ly f o r N o m a l M o d e ls O n ly f o r H i R e w in d M o d e ls Optional Parts Only for Jog Shuttle Models 3 Moving Mechanism Section 2 ...

Page 68: ...CHASSIS MV 025A MODEL KF 20 21P31 MODEL CONTENT MECHANICAL PARTS 5 2 ELECTRICAL PARTS 5 4 SECTION 5 RPL TVCR SERVICE MANUAL ...

Page 69: ...R 0029A A00 A01 A02 A03 A04 A11 A12 A21 A22 A23 A24 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 031 032 051 052 053 054 055 056 057 060 061 062 063 064 065 066 067 DECK ASSY DRUM CIRC ASSY ARM ASSY ARM ASSY BRACKET ASSY GEAR ASSY GEAR ASSY HOLDER ASSY BRACKET ASSY ARM ASSY LEVER ASSY BASE ASSY BASE ASSY BASE ASSY OPENER BASE ASSY REEL SPRING BRAKE ASSY SPRING BRAKE ASSY...

Page 70: ...5 106 107 108 109 110 111 112 113 114 115 116 401 406 407 409 410 426 504 517 518 GEAR SPRING LEVER PLATE LEVER BASE PLATE ASSY BRACKET HOLDER GUIDE HOLDER HOLDER LEVER BRACKET OPENER ARM SPRING BODY SPRING ARM SPRING LEVER PAN HEAD MACHINE SCREW PAN HEAD MACHINE SCREW S W SCREW TAP TITE B PAN HEAD PAN HEAD MACN SCREW S P WASH SCREW TAP TITE B PAN HEAD SCREW MACHINE WASHER WASHER WASHER P2 L D P2 ...

Page 71: ...KTC3205 Y KTC2236A TP KEC TR CHIP 2SC3875S ALY KEC TR CHIP 2SC3875S ALY KEC TR CHIP 2SA1504S ASY KEC TR CHIP 2SA1504S ASY KEC TR CHIP 2SC3875S ALY KEC TR CHIP 2SA1504S ASY KEC TR CHIP 2SA1504S ASY KEC TR KTC3198 TP KEC Y KTC1815 LOCA NO PART NO DESCRIPTION IC01 IC01S IC02 IC03 IC04 IC05 IC06 IC203 IC301 IC500 IC501 IC601 IC701 IC801 IC802 IC803 IC851 IC852 IC853 IC855 IC857 IC901 D01 D02 D03 D04 D...

Page 72: ...04 C107 C109 C200 C207 C214 C215 C223 C224 C226 C251 C262 C264 C302 C303 C305 C306 C307 C309 C310 C313 C316 C329 C330 C332 C333 C334 C335 C336 C338 C340 C341 C342 C343 C347 C350 C351 C353 C355 C356 C357 C359 C365 C367 C368 C369 C370 C371 0CE4763F618 0CE107DF618 0CN1030F679 0CE106DF618 0CE105DK618 0CE107DD618 0CE107DD618 0CE476DK618 0CF4741L438 0CF4741L438 0CE106DF618 0CE476DF618 0CE1063F618 0CE476...

Page 73: ... 100V K POLY TP 47UF STD 16V M FL TP5 LOCA NO PART NO DESCRIPTION C782 C783 C784 C785 C786 C787 C788 C801 C802 C805 C806 C807 C808 C809 C810 C811 C812 C813 C814 C816 C851 C852 C853 C854 C855 C856 C857 C858 C859 C860 C861 C865 C866 C867 C868 C869 C870 C871 C872 C874 C875 C876 C901 C902 C903 C904 C905 J275 L01S 0CE106DK618 0CQ1531N509 181 091U 181 015E 181 015F 0CK8210W515 181 013N 181 013P 0CE475DP...

Page 74: ...CONNECTOR GB201 2P TS B LGC LOCA NO PART NO DESCRIPTION P303 P602 P701 P703 P801A P801B P802A P802B P802B P802A P803A P803B P804 P804A P805 P805A P806 P901 P901A P902 P902A P903 PD04 F851 F852 F853 FR701 FR702 FR851 FR854 FR901 FR902 J258 R01 R02 R03 R06 R08 R08S R09S R09 R11 R12 R14 R17 R18 R20 R21J R22 R22J 561 234Z 366 932B 366 043K 366 009D 366 009D 366 009D 366 009D 366 009D 366 009D 366 009D...

Page 75: ...RT NO DESCRIPTION R321 R333 R334 R348 R360 R361 R363 R364 R365 R380 R381 R382 R503 R504 R511 R513 R519 R520 R521 R522 R524 R525 R529 R531 R541 R546 R550 R551 R552 R554 R558 R593 R601 R602 R603 R604 R605 R606 R607 R608 R609 R610 R701 R702 R703 R704 R705 R731 R732 R734 R735 R736 0RD1001F609 0RD1000F609 0RD1000F609 0RD1001F609 0RD2202F609 0RD1001F609 0RD4702F609 0RD4702F609 0RD4702F609 0RD1000F609 0R...

Page 76: ... RA07 RA11 RA20 RA22 RA23 RA30 RA33 VR01 SW01 SW03 SW04 SW05 SW06 SW07 SW08 SW11 SW12 SW13 SW14 SW804 FB801 FB802 FB803 FB851 L24J L222 L801 T301 T502 T503 T504 X01S X01 X02 X301 X501 Z100 A1 A1 A2 A3 0RD1000F609 0RS1501H609 0RS1501H609 0RS1501H609 0RD2204H609 0RD3902F609 0RD3902F609 0RD4700F609 0RD5600F609 0RD4700F609 0RD2700F609 0RD1202F609 180 F03M 6600RDB004C 140 315F 140 315F 140 315F 140 315...

Page 77: ...00MA 250V 5 2X20 CY CE SEMK JACK ASSY PMJ019A A V 2P WH YL REMOTE CONTROLLER RECEIVER 38KHZ SENSOR GP1S566 SHARP D 33 REEL SENSOR SENSOR GP1S566 SHARP D 33 REEL SENSOR HOLDER END SENSOR ASSY 33 DECK 49 HOLDER END SENSOR ASSY 33 DECK 49 JACK RCA PJ6037A HORIZONTAL 4 SOCKET CPT PCS030A 8PIN 14 360 THERMISTOR J503P84D140M290Q TUNER TAEL G579D LG MULTI FS W S 38 TUNER TAFD M232D LG MULTI VARISTOR SVC6...

Page 78: ......

Page 79: ......

Page 80: ...Aug 2002 Printed in Korea P NO 3828VD0067G ...

Search results

Summary of Contents for KF-20P31

Reviews:

Related manuals for KF-20P31

Brands by name

Popular brands

LG KF-20P31, Service Manual

Search results

Summary of Contents for KF-20P31

Reviews:

Related manuals for KF-20P31

Brands by name

Popular brands