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JVC AV-20420/SA Service Manual

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SERVICE MANUAL
2003
03
52111
VIDEO
VIDEO
STATUS
STATUS
DISPLAY
DISPLAY
1
PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2
SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
4
TROUBLE SHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
COLOR TELEVISION
AV-20420
AV-20421
SLEEP
SLEEP
TIMER
TIMER
POWER
POWER
INPUT
INPUT
1
2
3
4
5
6
7
8
9
100+
100+
0
RETURN+
RETURN+
MUTING
MUTING
V-CHIP
CHIP
+
CH
VOL
VOL
+
C H
MENU
MENU
EXIT
EXIT
VCR CONTROL
VCR CONTROL
CHANNEL
CHANNEL
POWER
POWER TV/VCR
TV/VCR
REW
REW
PLAY
PLAY
FF
FF
REC
REC
STOP PAUSE
STOP
PAUSE
RM-C205
RM-C205
TABLE OF CONTENTS
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD.
,
/SA
/SA
AV-20420
AV-20421
BASIC CHASSIS
FV5
No.52111
2003/03

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Summary of Contents for JVC AV-20420/SA

  • Page 1 AV-20420 AV-20421 SERVICE MANUAL COLOR TELEVISION 52111 2003 AV-20420 BASIC CHASSIS AV-20421 VIDEO VIDEO SLEEP SLEEP STATUS STATUS TIMER TIMER POWER POWER DISPLAY DISPLAY INPUT INPUT 100+ 100+ RETURN+ RETURN+ MUTING MUTING V—CHIP CHIP MENU MENU EXIT EXIT VCR CONTROL VCR CONTROL CHANNEL CHANNEL...
  • Page 2 AV-20420 AV-20421 SPECIFICATION Items Contents Dimensions (W x H x D) 50.3cm x 45.2cm x 49.3cm (19-7/8” x 17-7/8” x 19-1/2”) Mass 19.9 kg (43.8 Ibs) TV RF System CCIR(M) Color Sound System NTSC, BTSC system (Multi Channel Sound) TV Receiving Channels and Frequency VHF LOW 02ch~06ch : 54MHz~88MHz VHF HIGH...

  • Page 3: Precautions

    AV-20420 AV-20421 SECTION 1 PRECAUTIONS 1.1 SAFETY PRECAUTIONS (10) Isolation Check (Safety for Electrical Shock Hazard)After re-assembling the (1) The design of this product contains special hardware, many circuits product, always perform an isolation check on the exposed metal and components specially for safety purposes. For continued parts of the cabinet (antenna terminals, video/audio input and output protection, no changes should be made to the original design unless terminals, Control knobs, metal cabinet, screwheads, earphone jack,...

  • Page 4: Specific Service Instructions

    AV-20420 AV-20421 SECTION 2 SPECIFIC SERVICE INSTRUCTIONS 2.1 FEATURES • New chassis design enables use of a single board with simplified circuitry. • Provided with miniature tuner (TV/CATV). • Multifunctional remote control permits picture adjustment. • Adoption of the CHANNEL GUARD function prevents the specific channels from being selected, unless the “ID number” is key in. •...
  • Page 5 AV-20420 AV-20421 2.3 MAIN DIFFERENCE LIST Parts Name AV-20420 AV-20421 BODY COLOR BLACK WHITE FRONT CABINET LC10109-016A-A LC10109-017A-A POWER KNOB LC30376-001A-A LC30376-002A-A PUSH KNOB LC30271-001A-A LC30271-002A-A REAR COVER LC10108-006A-A LC10108-007A-A POWER CORD CLAMP LC20106-001D-A LC20106-002C-A REMOTE CONTROL UNIT RM-C205-1C RM-C205W-1C WHITE MARK (PACKING CASE) not used GQ40012-001A-A...
  • Page 6 AV-20420 AV-20421 2.4 DISASSEMBLY PROCEDURE 2.4.1 REMOVING THE REAR COVER 2.4.4 CHECKING THE MAIN PW BOARD (1) Unplug the power plug. (1) Pull out the MAIN CHASSIS (refer to REMOVING THE (2) Remove the 5 screws [A], and 2 screws [B] as shown in MAIN PWB).
  • Page 7 AV-20420 AV-20421 FRONT CABINET CRT SOCKET PWB (Within MAIN PWB) SPEAKER BRAIDED ASSY DEG. COIL MAIN PWB TUNER REAR COVER PWB STOPPER Fig.1 (No.52111)1-7...
  • Page 8 AV-20420 AV-20421 2.5 REPLACEMENT OF MEMORY IC 2.5.1 MEMORY IC This TV use memory IC. In the memory IC, there are memorized data for correctly operating the video and deflection circuits. When replacing the memory IC, be sure to use IC written with the initial values of data. 2.5.2 PROCEDURE FOR REPLACING MEMORY IC (1) Power off Switch the power off and unplug the power plug.
  • Page 9 AV-20420 AV-20421 2.5.3 SYSTEM CONSTANT SETTING Setting Item AV-20420 AV-20421 Setting Content AV-20220 AV-27220 AV-20220 MODEL AV-20220 C-20210 C-13210 V-CHIP CAN V-CHIP 2.5.4 USER SETTING VALUE Setting item Setting value 1. Use remote controller keys POWER CHANNEL CH 02 CHANNEL PRESET See OPERATING INSTRUCTIONS.
  • Page 10 AV-20420 AV-20421 2.5.5 SERVICE MENU SETTING ITEM Menu item Setting item Menu item Setting item PICTURE 1. BRIGHT GAME TINT 2. PICTURE COLOR 3. TV DETAIL PICTURE 4. TV BPF BRIGHT 5. TINT DETAIL 6. COLOR LOW LIGHT 7. EXT BRIGHT GREEN 8.
  • Page 11 AV-20420 AV-20421 2.6 REPLACEMENT OF CHIP COMPONENT 2.6.1 CAUTIONS (1) Avoid heating for more than 3 seconds. (2) Do not rub the electrodes and the resist parts of the pattern. (3) When removing a chip part, melt the solder adequately. (4) Do not reuse a chip part after removing it.

  • Page 12: Adjustment

    AV-20420 AV-20421 SECTION 3 ADJUSTMENT 3.1 ADJUSTMENT PREPARATION (1) There are 2 ways of adjusting this TV : One is with the REMOTE CONTROL UNIT and the other is the conventional method using adjustment parts and components. (2) The adjustment using the REMOTE CONTROL UNIT is made on the basis of the initial setting values. The setting values which adjust the screen to the optimum condition can be different from the initial setting values.

  • Page 13: Main Pwb

    AV-20420 AV-20421 3.4 ADJUSTMENT LOCATIONS FRONT CRT SOCKET PWB (Within MAIN PWB ASS'Y) TP-R TP-E (SOLDER SIDE) CRT EARTH (BRAIDED ASS'Y) FRONT MAIN PWB REMOCON VOL+ VOL- MENU RECEIVER POWER TIMER IC701 IC702 STEREO F901 DEG. TP-12B IC421 T131 R926 IC201 F902 TP-91...
  • Page 14 AV-20420 AV-20421 3.5 BASIC OPERATION OF SERVICE MENU 3.5.1 TOOL OF SERVICE MENU OPERATION Operate the SERVICE MENU with the REMOTE CONTROL UNIT. 3.5.2 SERVICE MENU ITEMS With the SERVICE MENU, various adjustments can be made, and they are broadly classified in the following items of settings. PICTURE This mode adjusts the VIDEO CHROMA and DEFLECTION control circuit.
  • Page 15 AV-20420 AV-20421 3.5.3 BASIC OPERATION IN SERVICE MENU (1) HOW TO ENTER THE SERVICE MENU Press the [SLEEP TIMER] key and set the SLEEP TIMER for SERVICE MENU “0 MIN”. PICTURE SOUND Then press the [DISPLAY] key and [VIDEO STATUS] key of GAME the remote control unit at the same time to enter the SERVICE LOW LIGHT...
  • Page 16 AV-20420 AV-20421 3.5.4 SERVICE SUB MENU [2] SCREEN [3] PICTURE MODE [1] SERVICE MENU (MAIN MENU) SERVICE MENU SOUND PICTURE GAME LOW LIGHT HIGH LIGHT RF AFC CHK 1. BRIGHT VCO(CW) STATUS ******** EXIT BY SELECT BY EXIT BY EXIT BY SELECT BY SELECT BY OPERATE BY...
  • Page 17 AV-20420 AV-20421 3.6 INITIAL SETTING VALUE OF SERVICE MENU (1) Adjustment of the SERVICE MENU is made on the basis of the initial setting values; however, the new setting values which set the screen in its optimum condition may differ from the initial setting. (2) Do not change the initial setting values of the setting (adjustment) items not listed in “ADJUSTMENTS PROCEDURE”.
  • Page 18 AV-20420 AV-20421 3.6.3 GAME MODE Setting item Variable range Initial setting value TINT ±20 COLOR ±20 PICTURE ±20 BRIGHT ±20 DETAIL ±15 3.6.4 LOW LIGHT MODE Setting item Variable range Initial setting value R CUTOFF 0 ~ 255 G CUTOFF 0 ~ 255 B CUTOFF 0 ~ 255...
  • Page 19 AV-20420 AV-20421 3.7 ADJUSTMENTS PROCEDURE 3.7.1 B1 POWER SUPPLY VOLTAGE CHECK Measuring Item Test point Adjustment part Description instrument B1 POWER DC voltmeter TP-91 (B1) (1) Receive the black-and-white signal. SUPPLY TP-E (2) Connect the DC voltmeter to TP-91 (B1) and TP-E. check (3) Confirm that the voltage is DC134V.
  • Page 20 AV-20420 AV-20421 3.7.3 DEFLECTION CIRCUIT Measuring Item Test point Adjustment part Description instrument V. SIZE Signal [PICTURE] (1) Receive the crosshatch signal. generator <13. V SIZE> (2) Select <13. V SIZE> of the PICTURE mode. (3) Set the initial setting value of <13 V SIZE>. Remote (4) Adjust <13.
  • Page 21 AV-20420 AV-20421 3.7.4 WHITE BALANCE Measuring Item Test point Adjustment part Description instrument WHITE Signal [PICTURE] (1) Receive the black-and-white signal (color off). BALANCE generator <1. BRIGHT> (2) Select <1. BRIGHT> of the PICTURE mode. (Low Light) (3) Set the initial setting value of the <1 BRIGHT>. Remote [LOW LIGHT] (4) Select the [LOW LIGHT] mode from SERVICE...
  • Page 22 AV-20420 AV-20421 Measuring Item Test point Adjustment part Description instrument WHITE Signal [HIGH LIGHT] (1) Receive the black-and-white signal (color off). BALANCE generator <G DRIVE> (2) Select the HIGH LIGHT mode of the SERVICE (High Light) <B DRIVE> MENU. Remote (3) Set the initial setting value of <G DRIVE>...
  • Page 23 AV-20420 AV-20421 Measuring Item Test point Adjustment part Description instrument Remote [PICTURE] (1) Receive the broadcast. CONTRAST control unit <2. PICTURE> (2) Select <2. PICTURE> of the PICTURE mode. (3) Set the initial setting value of the <2. PICTURE>. (4) If the contrast is not best with the initial setting value, make fine adjustment of the <2.
  • Page 24 AV-20420 AV-20421 Measuring Item Test point Adjustment part Description instrument SUB TINT Signal TP-R [PICTURE] [ Method of adjustment without measuring instrument ] generator TP-E <5. TINT> (1) Receive the broadcast. [CRT SOCKET (2) Select <5. TINT> of the PICTURE mode. Oscilloscope PWB] (3) Set the initial setting value of the <5.
  • Page 25 AV-20420 AV-20421 Measuring Item Test point Adjustment part Description instrument Signal R OUT [SOUND] (1) Receive the RF signal (no modulated sound signal) STEREO VCO generator [AUDIO OUT] <2. FH MON> from the antenna terminal. <3. ST VCO> (2) Select the <2. FH MON> of SOUND mode, and Frequency change the setting value from 0 to 1.
  • Page 26 AV-20420 AV-20421 Measuring Item Test point Adjustment part Description instrument TV audio L OUT [SOUND] (1) Input a stereo L signal (300Hz) from the TV audio SEPARATION multiplex R OUT <6. LOW SEP> multiplex signal generator to the antenna terminal. signal [AUDIO OUT] <7.
  • Page 27 AV-20420 AV-20421 3.7.7 PURITY AND CONVERGENCE PURITY ADJUSTMENT (1) Demagnetize CRT with the demagnetizer. WEDGE DEFLECTION YOKE (2) Loosen the retainer screw of the deflection yoke. (3) Remove the wedges. (4) Input a green raster signal from the signal generator, and turn the screen to green raster.
  • Page 28 AV-20420 AV-20421 STATIC CONVERGENCE ADJUSTMENT (1) Input a crosshatch signal. (2) Using 4-pole convergence magnets, overlap the red and blue lines in the center of the screen (Fig.1) and turn them (FRONT VIEW) to magenta (red/blue). (3) Using 6-pole convergence magnets, overlap the magenta (red/blue) and green lines in the center of the screen and turn them to white.
  • Page 29 AV-20420 AV-20421 3.7.8 HOW TO CHECK THE HIGH VOLTAGE HOLD DOWN CIRCUIT 3.7.8.1 HIGH VOLTAGE HOLD DOWN CIRCUIT After repairing the high voltage hold down circuit shown in Fig.1. This circuit shall be checked to operate correctly. 3.7.8.2 CHECKING OF THE HIGH VOLTAGE HOLD DOWN CIRCUIT (1) Turn the power switch to on.

  • Page 30: Trouble Shooting

    AV-20420 AV-20421 SECTION 4 TROUBLE SHOOTING 4.1 SELF CHECK FUNCTIONS 4.1.1 OUTLINE This model has self check functions given below. When a malfunction has been detected, the POWER is turned off and the LED flashes to inform of the failure . The malfunction is detected by the signal input state of the control line connected to the microcomputer. 4.1.2 SELF CHECK ITEMS Check item Details of detection...
  • Page 31 AV-20420 AV-20421 (No.52111)1-31...
  • Page 32 AV-20420 AV-20421 JVC SERVICE & ENGINEERING COMPANY OF AMERICA DIVISION OF JVC AMERICAS CORP. www.jvcservice.com(US Only) JVC CANADA INC. Head office : 21 Finchdene Square Scarborough, Ontario M1X 1A7 (416)293-1311 (No.52111) Printed in Japan 200303WPC...

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Av-20421/saAv-20420Av-20421