JVC AV-21YN14/P, AV-21YT14/P Service Manual

YA143200412

SERVICE MANUAL

FLAT COLOR TELEVISION

AV-21YN14/P,
AV-21YT14

[AV-21YT14/P][AV-21YN14/P]

/P

BASIC CHASSIS

CW

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30

COPYRIGHT © 2004 Victor Company of Japan, Limited

No.YA143

2004/12

SPECIFICATION

Items

Dimensions (W × H × D) 64.9cm × 47.05cm × 47.75cm

Mass 21kg

TV RF System M

Color System TV Mode

Video Mode

Stereo System Mono MTS (Multi-Channel Television Sound)

Receiving Frequency VHF Low

VHF High

Intermediate
Frequency

Color Sub Carrier Frequency 4.43MHz (PAL), 4.40MHz/4.25MHz (SECAM), 3.58MHz/4.43MHz (NTSC)

Aerial Input Terminal 75Ω unbalanced, coaxial

Power Input AC110V-AC240V, 50Hz / 60Hz (Operating Voltage AC90V ~ AC260V)

Power Consumption 81W (Max.) / 57W (Avg.) 91W (Max.) / 65W (Avg.)

Picture Tube A51LZM10X

Screen Size Visible size :51.0cm (Diagonal) / 42.0cm × 31.85cm (H × V)

High Voltage 26kV ± 1.5kV (at zero beam current)

Speaker 6cm × 12cm, Oval type × 2

Audio Output 3W 3W + 3W

Video / Audio Input
[1/2]

Video / Audio Output Video 1V(p-p), 75Ω, RCA pin jack × 1

Headphone 3.5mm stereo mini jack × 1

Remote Control Unit RM-C1262-2H

Video [1/2] 1V(p-p), negative sync, 75Ω, RCA pin jack × 2

Audio [1/2] 500mV(rms)(-4dBs ),

NTSC3.58
PAL / SECAM / NTSC3.58 / NTSC4.43

46.25MHz ~ 168.25MHz (AU0 ~ S10)

175.25MHz ~ 463.25MHz (E5 ~ S41)

UHF

471.25MHz ~ 863.25MHz (E21 ~ CHINA 57)

CATV

Mid : X ~ Z, S1 ~ S10
Super: S11 ~ S20
Hyper: S21 ~ S41

VIF 38.0MHz

SIF 33.5MHz (4.5MHz)

21-inch, aspect ratio 4:3, conventional square face type, tinted

high impedance, RCA pin jack × 2

Audio 500mV(rms)(-4dBs), Low impedance (400Hz

when modulated 100%), RCA pin jack × 1

(AA/R06/UM-3 battery × 2)

AV-21YN14/P AV-21YT14/P

Contents

500mV(rms)(-4dBs),

high impedance, RCA pin jack × 4

500mV(rms)(-4dBs), Low impedance (400Hz

when modulated 100%), RCA pin jack × 2

RM-C1282-2H

(AA/R06/UM-3 battery × 2)

Design & specifications are subject to change without notice.

1-2 (No.YA143)

SECTION 1

PRECAUTION

1.1 SAFETY PRECAUTIONS

(1) The design of this product contains special hardware,

many circuits and components specially for safety
purposes. For continued protection, no changes should be
made to the original design unless authorized in writing by
the manufacturer. Replacement parts must be identical to
those used in the original circuits. Service should be
performed by qualified personnel only.

(2) Alterations of the design or circuitry of the products should

not be made. Any design alterations or additions will void
the manufacturer's warranty and will further relieve the
manufacturer of responsibility for personal injury or
property damage resulting therefrom.

(3) Many electrical and mechanical parts in the products have

special safety-related characteristics. These
characteristics are often not evident from visual inspection
nor can the protection afforded by them necessarily be
obtained by using replacement components rated for
higher voltage, wattage, etc. Replacement parts which
have these special safety characteristics are identified in
the parts list of Service manual. Electrical components

having such features are identified by shading on the
schematics and by ( ) on the parts list in Service
manual. The use of a substitute replacement which does

not have the same safety characteristics as the
recommended replacement part shown in the parts list of
Service manual may cause shock, fire, or other hazards.

(4) Don't short between the LIVE side ground and

ISOLATED (NEUTRAL) side ground or EARTH side
ground when repairing.

Some model's power circuit is partly different in the GND.
The difference of the GND is shown by the LIVE : ( ) side
GND, the ISOLATED (NEUTRAL) : ( ) side GND and
EARTH : ( ) side GND.
Don't short between the LIVE side GND and ISOLATED
(NEUTRAL) side GND or EARTH side GND and never
measure the LIVE side GND and ISOLATED (NEUTRAL)
side GND or EARTH side GND at the same time with a
measuring apparatus (oscilloscope etc.). If above note will
not be kept, a fuse or any parts will be broken.

(5) If any repair has been made to the chassis, it is

recommended that the B1 setting should be checked or
adjusted (See B1 POWER SUPPLY check).

(6) The high voltage applied to the picture tube must conform

with that specified in Service manual. Excessive high
voltage can cause an increase in X-Ray emission, arcing
and possible component damage, therefore operation
under excessive high voltage conditions should be kept to
a minimum, or should be prevented. If severe arcing
occurs, remove the AC power immediately and determine
the cause by visual inspection (incorrect installation,
cracked or melted high voltage harness, poor soldering,
etc.). To maintain the proper minimum level of soft X-Ray
emission, components in the high voltage circuitry
including the picture tube must be the exact replacements
or alternatives approved by the manufacturer of the
complete product.

(7) Do not check high voltage by drawing an arc. Use a high

voltage meter or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground frame

and connecting the other end of the lead through a 10kΩ

2W resistor to the anode button.

(8) When service is required, observe the original lead dress.

Extra precaution should be given to assure correct lead
dress in the high voltage circuit area. Where a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the
manufacturer's replacement components.

(9) Isolation Check (Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an
isolation check on the exposed metal parts of the cabinet
(antenna terminals, video/audio input and output terminals,
Control knobs, metal cabinet, screw heads, earphone jack,
control shafts, etc.) to be sure the product is safe to operate
without danger of electrical shock.

a) Dielectric Strength Test

The isolation between the AC primary circuit and all metal
parts exposed to the user, particularly any exposed metal
part having a return path to the chassis should withstand a
voltage of 3000V AC (r.m.s.) for a period of one second. (.
. . . Withstand a voltage of 1100V AC (r.m.s.) to an
appliance rated up to 120V, and 3000V AC (r.m.s.) to an
appliance rated 200V or more, for a period of one second.)
This method of test requires a test equipment not generally
found in the service trade.

b) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use
a line isolation transformer during this check.). Using a
"Leakage Current Tester", measure the leakage current
from each exposed metal part of the cabinet, particularly
any exposed metal part having a return path to the chassis,
to a known good earth ground (water pipe, etc.). Any
leakage current must not exceed 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).

Alternate Check Method

Plug the AC line cord directly into the AC outlet (do not
use a line isolation transformer during this check.). Use

an AC voltmeter having 1000Ω per volt or more
sensitivity in the following manner. Connect a 1500Ω
10W resistor paralleled by a 0.15µF AC-type capacitor

between an exposed metal part and a known good earth
ground (water pipe, etc.). Measure the AC voltage
across the resistor with the AC voltmeter. Move the
resistor connection to each exposed metal part,
particularly any exposed metal part having a return path
to the chassis, and measure the AC voltage across the
resistor. Now, reverse the plug in the AC outlet and
repeat each measurement. Any voltage measured must
not exceed 0.75V AC (r.m.s.). This corresponds to

0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.3V AC
(r.m.s.). This corresponds to 0.2mA AC (r.m.s.).

AC VOLTMETER
(HAVING 1000 /V,
OR MORE SENSITIVITY)

0.15 F AC-TYPE

PLACE THIS PROBE

1500 10W

GOOD EARTH GROUND

ON EACH EXPOSED
ME TAL PAR T

(No.YA143)1-3

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

2.1 FEATURES

• New chassis design enables use of an interactive on-screen control.

• Pure flat CRT produces fine textured picture in every detail.

• Wide range voltage (110V ~ 240V) for AC power input.

• With AUDIO/VIDEO input terminals.

2

C bus control utilizes single chip ICs.

•I

• By means of AUTO PROGRAM, the TV stations can be selected automatically and the TV channels can also be rearranged
automatically.

• Built-in OFF TIMER & RETURN +.

2.2 MAIN DIFFERENCE LIST

Items AV-21YN14/P AV-21YT14/P

STEREO SYSTEM Mono MTS (Multi-Channel Television Sound)

AUDIO OUTPUT 3W 3W + 3W

POWER CONSUMPTION 81W (Max.) / 57W (Avg.) 91W (Max.) / 65W (Avg.)

1-4 (No.YA143)

2.3 FUNCTIONS

 REMOTE CONTROL UNIT

RM-C1262-2H [AV-21YN14/P]

10

1

11

2

3

4

5

6

7
8

9

12

13

14

15

16

17

PICTURE BOOSTER key

1

COLOR SYSTEM key

2

FAVORITE CHANNEL keys

3

4

TV / VIDEO key

5

PICTURE MODE key

6

CLOSED CAPTION key

7

OFF TIMER key

8

RETURN + key

9

DISPLAY / BACK key

10

CHANNEL (-/+) keys

11

POWER key

Number keys

12

13

100+ key

14

MENU/OK key

15

MENU (

16

MUTING key
VOLUME (-/+) keys

17

/

,

/

) keys

RM-C1282-2H [AV-21YT14/P]

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15
16

17

18

19

20

21

COLOR SYSTEM key

1

FAVORITE CHANNEL keys

2

DISPLAY BACK key

3

MENU ( / , / ) keys

4

CLOSED CAPTION key

5

SOUND TURBO key

6

7

PICTURE MODE key

8

RETURN + key

9

OFF TIMER key

CHANNEL (-/+) keys

10

PICTURE BOOSTER key

11

ECO key

12

POWER key

13

14

TV / VIDEO key

MENU (OK) key

15

16

MUTING key

17

Number keys

18

100+ key

VOLUME (-/+) keys

19

20

Not used

21

CINEMA SURROUND key

(No.YA143)1-5

 FRONT PANEL CONTROLS

[AV-21YN14/P]

[AV-21YT14/P]

AUDIO

VIDEO

IN (VIDEO-2)

1

1

2

3

4

5

6

3

2

HEADPHONE jack

IN (VIDEO-2) : VIDEO

IN (VIDEO-2) : AUDIO

MENU (OK) button

CHANNEL (-/+) buttons

VOLUME (-/+) buttons

MENU

OK

4

POWER

TIMER

5

6

7

7

Remote control sensor

8

TIMER lamp

9

POWER lamp

10

MAIN POWER button

9

8

10

V L/MONO
IN (VIDEO-2)

1

2

HEADPHONE jack

1

IN (VIDEO-2) : VIDEO

2

IN (VIDEO-2) : AUDIO L/MONO

3

4

IN (VIDEO-2) : AUDIO R

5

MENU (OK) button

CHANNEL (-/+) buttons

6

R

3

4

MENU

OK

5

POWER

TIMER

6

7

8

7

VOLUME (-/+) buttons

8

Remote control sensor

9

TIMER lamp

10

POWER lamp

11

MAIN POWER button

9

10

11

1-6 (No.YA143)

 REAR TERMINAL
[AV-21YN14/P]

VIDEO-1 INPUT TERMINAL

[AV-21YT14/P]

VIDEO-1

OUTPUT

INPUT

VIDEO

AUDIO

1 2 3 4

VIDEO

1

AUDIO

2

OUTPUT TERMINAL

3

AUDIO

4

VIDEO

Aerial input terminal

5

7

1

2

VIDEO-1

INPUT

V

L

/

MONO

R

3

4 5

OUTPUT

V

L

R

6

VIDEO-1 INPUT TERMINAL

VIDEO

1

AUDIO L/MONO

2

AUDIO R

3

OUTPUT TERMINAL

VIDEO

4

AUDIO L

5

AUDIO R

6

9

Aerial input terminal

7

(No.YA143)1-7

2.4 MAIN CPU [MAIN PWB : IC701] PIN FUNCTION

Pin no. Pin name I/O Remark

1 VssP2 - GND

2 VssC4 - GND

3 V1.8C4 I 1.8V (Digital)

4 V3.3A3 I 3.3V

5 VrefP_Sdac I 3.3V (Positive)

6 VrefN_Sdac - GND

7 VrefP_Sdac I 3.3V (Negative)

8 VrefN_Sdac - GND

9 VrefP_Sdac I 3.3V (Positive)

10 XtalIn I 24.567MHz for system clock

11 XtalOut O 24.567MHz for system clock

12 VssA1 - GND

13 NECK I V-guard input/ I/O switch

14 CONT I 1.8V regulator control

15 V5P1 I +5V

16 Ph2 - Phase-2 filter

17 Ph1 - Phase-1 filter

18 Gnd1 - GND

19 SecPll - SECAM PLL decoupling

20 Dec8G - Bandgap decoupling

21 EW O East-West drive output

22 VDRB- O Vertical drive B output

23 VDRA+ O Vertical drive A output

24 Vif1 I Video IF input 1

25 Vif2 I Video IF input 2

26 Vsc - Vertical sawtooth capacitor

27 Iref I Reference current input

28 GndIF - GND

29 Sif1 I Sound IF input 1

30 Sif2 I Sound IF input 2

31 AGC O Tuner AGC output

32 EHT I EHT/overvoltage protection input

33 Ssif/RefIn/Avl/RefOut O

34 L3 I Audio-L3 input (left signal)

35 R3 I Audio-R3 input (right signal)

36 L_OUT O Audio L output

37 R_OUT O Audio R output

38 DecsDem - Decoupling sound demodulator

39 QssO/AmO/AudeEm O QSS intercarrier output / AM output /

40 Gnd2 - GND

41 PllIf - IF-PLL loop filter

42 SifAgc - AGC sound IF

43 IfVo/FmRo/DvbO O Not used

44 NC O Not used

45 V8AudioSwitches I 8V

46 AgcSsif - AGC capacitor second sound IF

47 V5P2 I 5V

48 V_OUT O Video output

49 L1 I Audio-L1 input

50 R1 I Audio-R1 input

51 V3 I Video V3 input

52 C4 I Not used

53 Audio2InL I Not used

54 Audio2InR I Not used

55 V2/Y I Video 2 input

56 L2 I Audio L2 input (Left signal)

57 R2 I Audio R2 input (right signal)

58 Y3/Cvbs I S-Video Y1 input

59 C1 I S-Video C1 input

60 AudioLsL O Audio L output for audio power amplifier

61 AudioLsR O Audio R output for audio power amplifier

62 HP_L O Headphone L

63 HP_R O Headphone R

Automatic Volume Levelling/ sound IF input /
subcarrier reference output / external reference
signal input for I signal mixer for DVB operation

deemphasis / (front-end audio out)

Pin no. Pin name I/O Remark

64 CVBSO/PIP O CVBS / PIP output

65 SVM O Scan velocity modulation output

66 FbiSo I Flyback input/sandcastle output

67 Hout O Horizontal output

68 VssComb - GND

69 V5Comb I 5V

70 Vin/R2/Pr I PIP R input

71 Uin/B2/Pb I PIP B input

72 Yin/G2/Y I PIP G input

73 Ysync I Not used

74 Yout O Not used

75 Uout/INSSW2 I YUV insertion input

76 NC O Not used

77 INSSW3 I YUV insertion input

78 R3/Pr I Component PR input (Video-2)

79 G3/Y I Component Y input (Video-2)

80 B3/Pb I Component PB input (Video-2)

81 Gnd3 - GND

82 V5P3 I 5V

83 BCL I Beam current limiter input

84 BLKIN I Black current input

85 Rout O R output

86 Gout O G output

87 Bout O B output

88 V3.3A1 I 3.3V

89 RefAdN - GND

90 V3.3RefAdP I 3.3V (Positive)

91 RefAd I 3.3/2V

92 GndA - GND

93 V1.8A I 1.8V

94 V3.3A2 I 3.3V

95 VssADC - GND

96 V1.8ADC I 1.8V

97 REMOTE I Remote control

98 PW_LED I POWER LED control

99 P11/TO I POWER LED control

100 V1.8C2 I 1.8V

101 VssC2 - GND

102 COMPONENT-PIP - Not used

103

COMB_SW_NT3.5/OTHER

104 VER_PROTECT O X-ray protect

105 S_REDUCE O Sound control

106 P00/I2SDI1 O Not used

107 POWER O SUB POWER control

108 SCL1 I I2C bus clock

109 SDA1 I/O I2C bus clock

110 V3.3P I 3.3V

111 ROTATION O ROTATION

112 3.58/OTHER O

113 A_MUTE O Audio muting

114 4.5/OTHER O NTSC 4.43 detection

115 PROT I Protect

116 ECO_IN I ECO sensor level detection

117 V1.8C1 I 1.8V (Digital)

118 DecV1V8 I 1.8V

119 KEY_IN I Key scan data

120 VDO_DET I Video DET input

121 VSSC1+P1 - Digital GND

122 P24/PWM3 I S-Video DET input

123 P25/PWM4 O GTVA_reset

124 V1.8C3 I 1.8V (Digital)

125 VssC3 - GND

126 P12/Int2 I External interrupt

127 SDA0 I/O I2C bus data (for memory)

128 SCL0 I I2C bus clock (for memory)

- Not used

NTSC 3.58 detection

1-8 (No.YA143)

SECTION 3

DISASSEMBLY

3.1 DISASSEMBLY PROCEDURE

3.1.1 REMOVING THE REAR COVER

• Unplug the power cord.
(1) Remove the 9 screws [A] and 2 screws [B] as shown in

Fig.1.

(2) Withdraw the REAR COVER toward you.

CAUTION:

When reinstalling the rear cover, carefully push it inward after
inserting the MAIN PWB into the REAR COVER groove.

3.1.2 REMOVING THE MAIN PW BOARD

• Remove the REAR COVER.
(1) Slightly raise the both sides of the MAIN PWB by hand.
(2) Withdraw the MAIN PWB backward.

(If necessary, take off the wire clamp and connectors, etc.)

3.1.3 REMOVING THE SPEAKER

• Remove the REAR COVER.
(1) Remove the 4 screws [C] as shown in Fig.1.

3.1.4 CHECKING THE MAIN PW BOARD

• To check the back side of the MAIN PWB.
(1) Pull out the MAIN PWB. (Refer to REMOVING THE MAIN

PW BOARD).

(2) Erect the MAIN PWB vertically so that you can easily check

its back side.

CAUTIONS:

• Before turning on power, make sure that the CRT earth wire

and other connectors are properly connected.

• When repairing, connect the DEG. COIL to the DEG.

connector on the MAIN PWB.

• When repairing, connect the DEG. COIL to the DEG.

connector on the MAIN PWB.

3.1.5 WIRE CLAMPING AND CABLE TYING

(1) Be sure to clamp the wire.
(2) Never remove the cable tie used for tying the wires

together.
Should it be inadvertently removed, be sure to tie the wires
with a new cable tie.

(No.YA143)1-9

SPEAKER

PICTURE TUBE

FRONT CABINET

C

(x4)

SPEAKER

MAIN PWB
(CRT SOCKET PWB)

FBT

[AV-21YT14/P]

C

(x4)

MAIN PWB

REAR COVER

FRONT CABINET

(x9)

A

B

(x2)

1-10 (No.YA143)

Fig.1