JVC AV-20N8(BK) Service Manual
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JVC AV-20N8(BK) Service Manual

JVC AV-20N8(BK) Service Manual

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SERVICE MANUAL
CONTENTS
SPECIFICATIONS ........................................................................................................................... 2
SAFETY PRECAUTIONS ................................................................................................................ 3
FEATURES ...................................................................................................................................... 4
OPERATING INSTRUCTIONS (APPENDED) .............................................................................. 1-1
SPECIFIC SERVICE INSTRUCTIONS ............................................................................................ 4
SERVICE ADJUSTMENTS ............................................................................................................ 10
STANDARD CIRCUIT DIAGRAM (APPENDED) ......................................................................... 2-1
PARTS LIST ................................................................................................................................... 27
COPYRIGHT © 2000 VICTOR COMPANY OF JAPAN, LTD.
COLOUR TELEVISION
AV-20N8
−
+
−
+
(BK)
No. 56030
AV-20N8
AV-20N8
BASIC CHASSIS
CL-M
No. 56030
1
Jul. 2000

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Summary of Contents for JVC AV-20N8(BK)

  • Page 1: Table Of Contents

    AV-20N8 AV-20N8 SERVICE MANUAL COLOUR TELEVISION BASIC CHASSIS CL-M AV-20N8 (BK) − − CONTENTS SPECIFICATIONS ........................... 2 SAFETY PRECAUTIONS ........................ 3 FEATURES ............................4 OPERATING INSTRUCTIONS (APPENDED) ................1-1 SPECIFIC SERVICE INSTRUCTIONS .................... 4 SERVICE ADJUSTMENTS ......................10 STANDARD CIRCUIT DIAGRAM (APPENDED) ................. 2-1 PARTS LIST ...........................

  • Page 2: Specifications

    AV-20N8 SPECIFICATIONS Item Content Dimensions (W × H × D) 619mm × 458mm × 488mm Mass 19kg TV RF System B / G, I, D / K, K1, M Colour System TV Mode PAL / SECAM / NTSC3.58 / NTSC4.43 VIDEO Mode PAL / SECAM / NTSC3.58 / NTSC4.43 Stereo System...

  • Page 3: Safety Precautions

    AV-20N8 SAFETY PRECAUTIONS 1. The design of this product contains special hardware, many 8. When service is required, observe the original lead dress. Ex- circuits and components specially for safety purposes. For con- tra precaution should be given to assure correct lead dress in tinued protection, no changes should be made to the original the high voltage circuit area.

  • Page 4: Features

    AV-20N8 FEATURES New chassis design enables use of an interactive on-screen control. Wide range voltage for AC power input. With AUDIO / VIDEO INPUT & OUTPUT terminals. MUTING button can reduce the audio level to zero instantly. Functional remote control to operate TV set (for channel select, volume control, power ON/OFF, etc.) from a distance. C bus control utilizes single chip ICs for IF, V/C (Video/Chroma) and VSM (Video Status Memory).
  • Page 5 AV-20N8 FRONT CABINET SPEAKER (×2) CRT SOCKET PWB (Within MAIN PWB) MAIN PWB A2 PWB SPEAKER (×2) REAR COVER (×2) (×6) No. 56030...

  • Page 6: Replacement Of Memory Ic

    AV-20N8 REPLACEMENT OF MEMORY IC MEMORY IC SERVICE MENU This TV uses the following memory IC. Memory IC: IC1702 on MAIN PW Board SERVICE MENU The memory IC memorizes data for correctly operating the video and deflection circuits. When replacing the memory IC, 1.
  • Page 7 AV-20N8 NAME OF REMOTE CONTROL KEYS POWER DISPLAY DISPLAY MENU − − MENU MENU MENU LIVE SPATIAL MENU − CHANNEL VOLUME SYSTEM PICTURE COLOUR MUTING SOUND BOOSTER TV/VIDEO I/II PICTURE MODE PICTURE MODE CHANNEL SCAN RETURN+ -/-- ECO SENSOR OFF TIMER SETTING OF SYSTEM CONSTANT SET Table 1 Setting item...
  • Page 8 AV-20N8 SERVICE MENU SETTING ITEMS Table 3 Service menu Setting item Service menu Setting item 1. IF 1. VCO 3. VSM PRESET TINT 2. DELAY POINT (BRIGHT/STD/SOFT) COLOUR BRIGHT Do not adjust. CONT. 2. V / C 1. CUTOFF(R/G/B) SHARP 2.
  • Page 9 AV-20N8 REPLACEMENT OF CHIP COMPONENT 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. SOLDERING IRON 1.

  • Page 10: Service Adjustments

    AV-20N8 SERVICE ADJUSTMENTS BEFORE STARTING SERVICE ADJUSTMENT 7. Preparation for adjustment (presetting): 1. There are 2 ways for adjusting this TV: One is with the Unless otherwise specified in the adjustment items, preset the REMOTE CONTROL UNIT and the other is the conventional following functions with the remote control unit.
  • Page 11 AV-20N8 3. BASIC OPERATION IN SERVICE MENU SERVICE MENU (1) How to enter SERVICE MENU Press the DISPLAY key and the PICTURE MODE key on SERVICE MENU the remote control unit simultaneously. The SERVICE MENU screen will be displayed. (See Fig. 1.) 1.
  • Page 12 AV-20N8 (3) Method of Setting *Once the setting values are set, they are memorized automatically. *It must not adjust without inputting a signal. 1) 1. IF [1. VCO] (a) 1 Key ......... Select 1. IF. (b) 1 Key ......... Select 1. VCO. (CW) (c) VCO(CW) TRANSF.
  • Page 13 AV-20N8 ADJUSTMENT LOCATIONS MAIN PWB FRONT TIMER ECO SENSOR MENU POWER REMOCON IC701 RECEIVER F901 MEMORY S901 POWER SW IC702 IC201 CN001 T101 TU001 1 Pin TP-91(B1) UPPER : FOCUS 2 Pin NC LOWER : SCREEN 3 Pin X-ray1 4 Pin X-ray2 5 Pin TP-E (") CRT SOCKET PWB A2 PWB...
  • Page 14 AV-20N8 ADJUSTMENTS B1 POWER SUPPLY Measuring Description Item Test point Adjustment part instrument Check of Signal TP-91 (B1) 1. Receive a whole black signal. B1 POWER Generator TP-E (" " " " " ) 2. Connect a DC voltmeter between TP-91 (B1) and TP-E (") SUPPLY (between pins 1 and 5 of the connector S1).
  • Page 15 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment Remote DELAY POINT 1. Receive a black and white signal (colour off). of DELAY control unit (AGC TAKE-OVER) 2. Select 1. IF from the SERVICE MENU. POINT 3. Select 2. DELAY POINT by pressing the 2 key on the remote control.
  • Page 16 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment Signal 1. CUTOFF (R) 1. Receive a black and white signal (colour off). of WHITE generator CUTOFF (G) 2. Select 2. V/C from the SERVICE MENU. 3. Select 1. CUTOFF (R), (G) and (B) with MENU a key, and BALANCE CUTOFF (B) (Low light)
  • Page 17 AV-20N8 Measuring Description Item Test point Adjustment part instrument 1. Receive any broadcast. Adjustment Remote 3. BRIGHT 2. Select 2. V/C from the SERVICE MENU. control unit 3. Select 3. BRIGHT with the MENU a key. 4. Set the initial setting value with the MENU − or + key. BRIGHT 5.
  • Page 18 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment Signal TP-47G 5. COLOUR [Method of adjustment using measuring instrument] of SUB generator TP-E (" " " " " ) COLOUR-II [CRT Oscillo- SOCKET PAL COLOUR (PAL COLOUR) scope PWB] 1.
  • Page 19 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment Remote 6. TINT [Method of adjustment without measuring instrument] control unit SUB TINT-I NTSC 3.58 TINT (NTSC 3.58 TINT) 1. Receive a NTSC 3.58 colour bar signal (full field colour bar 75% white).
  • Page 20 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment Remote [Method of adjustment without measuring instrument] of BLACK control unit OFFSET-I (SECAM) 7. BLACK OFFSET 1. Receive a SECAM broadcast. (R-Y) 2. Select 2. V/C from the SERVICE MENU. 3.
  • Page 21 AV-20N8 DEFLECTION CIRCUIT ADJUSTMENT There are 2 modes of adjustment (initial setting value) — 50Hz mode and 60Hz mode — depending upon the kind of signals (vertical frequency 50Hz / 60Hz). When adjusted in 50Hz mode, 60Hz mode will be automatically set. The setting (adjustment) using the remote control unit is made on the basis of the initial setting values.
  • Page 22 AV-20N8 Measuring Description Item Test point Adjustment part instrument Adjustment 10. H. CENTER 6. Receive a circle pattern signal. 7. Select 10. H. CENTER with the MENU a key. H. CENTER 8. Set the initial setting value of 10. H. CENTER with the MENU −...
  • Page 23 AV-20N8 VSM PRESET ADJUSTMENT Measuring Description Item Test point Adjustment part instrument Setting of Remote TINT (VSM PRESET) control unit COLOUR 1. Select 3. VSM PRESET from the SERVICE MENU. PRESET BRIGHT 2. Select BRIGHT with the PICTURE MODE key. 3.
  • Page 24 AV-20N8 PURITY, CONVERGENCE ADJUSTMENT PURITY ADJUSTMENT 1. Demagnetize CRT with the demagnetizer. WEDGE DEFLECTION YOKE 2. Loosen the retainer screw of the deflection yoke. 3. Remove the wedges. (Fig. 1.) 4. Input a green raster signal from the signal generator, and turn the screen to green raster.
  • Page 25 AV-20N8 STATIC CONVERGENCE ADJUSTMENT 1. Input a cross-hatch signal. 2. Using 4-pole convergence magnets, overlap the red and blue lines in the center of the screen (Fig. 1) to turn them to magenta (red/blue). (FRONT VIEW) 3. Using 6-pole convergence magnets, overlap the magenta (red/ blue) and green lines in the center of the screen to turn them to white.
  • Page 26 AV-20N8 SELF-CHECK FUNCTIONS 1. Outline This model has self-check functions given below. When an abnormality has been detected, the SUB POWER is turned off and the ON TIMER LED flashes to inform of the failure. An abnormality is detected by the signal input state of the control line connected to the microcomputer.

  • Page 27: Parts List

    AV-20N8 VICTOR COMPANY OF JAPAN, LIMITED TELEVISION RECEIVER DIVISION 1106 Heta, Iwai-city, Ibaraki-prefecture, 306-0698, Japan AV20N8BK-BK #3 CTH 0007 No. 56030...

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