JVC AV-14AG16/U User manual

SERVICE MANUAL
COPYRIGHT © 2006 Victor Company of Japan, Limited No.YA392
2006/6
COLOUR TELEVISION
YA39220066
AV-14AG16/U
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24
BASIC CHASSIS
CG4

1-2 (No.YA392)
SPECIFICATION
Design and specifications are subject to change without notice.
Items Contents
Dimensions (W ×H ×D) 36.4 cm ×33.4 cm ×37.4 cm
Mass 9 kg
TV RF System B/G, I, D/K, M
Colour System PAL
SECAM
NTSC 3.58 / NTSC 4.43
Receiving
Frequency
VHF Low
VHF High
UHF
CATV
46.25 MHz to 140.25 MHz
147.25 MHz to 423.25 MHz
431.25 MHz to 863.25 MHz
Mid (X to Z+2, S1 to S10) / Super (S11 to S20) / Hyper (S21 to S41) bands
Intermediate Frequency VIF 38.0 MHz (B/G, I, D/K, M)
SIF 32.5 MHz (5.5 MHz: B/G)
32MHz (6.0 MHz: I)
31.5MHz (6.5 MHz: D/K)
33.5MHz (4.5 MHz: M)
Colour Sub Carrier PAL
SECAM
NTSC
4.43 MHz
4.40625 MHz / 4.25 MHz
3.58 MHz / 4.43 MHz
Power Input AC110 V to AC240 V, 50 Hz / 60Hz
Power Consumption 68 W (Max) / 47W(Avg)
Picture Tube Visible size: 34 cm measured diagonally ( H : 28.7 cm ×V : 21.7 cm)
High Voltage 22.5 kV±1.5kV (at zero beam current)
Speaker 8 cm Round type ×1
Audio Power Output 3 W (monaural)
Aerial Input Terminal 75 Ωunbalanced, coaxial
Input Terminal
[Front / Rear]
Video
Audio
1 V(p-p), 75 Ω, RCA pin jack ×2
500 mV(rms) (-4 dBs), High impedance, RCA pin jack ×2
Output Terminal
[Rear]
Video
Audio
1 V(p-p), 75Ω, RCA pin jack ×1
500 mV(rms) (-4 dBs), Low impedance, RCA pin jack ×1
Headphone Jack 3.5 mm mini jack ×1
Remote Control Unit RM-C360GY (Battery size : AA / R6 / UM-3 ×2)

(No.YA392)1-3
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 ADJUSTMENT OF B1 POWER SUPPLY).
(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 1000Ωper 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)
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART
1500 10W
0.15 F AC-TYPE
GOOD EARTH GROUND

1-4 (No.YA392)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 FEATURES
PICTURE MODE
This function can adjust the picture settings automatically.
There are BRIGHT, STANDARD and SOFT in the PICTURE
MODE.
RETURN +
This function can set a channel you frequently view to the
Return Channel and you can view that channel at any time with
one-touch.
CHILD LOCK
Use this function to prevent children from operating the TV
without parental consent.
VNR
This function can reduce the picture noise.
2.2 TECHNINAL INFORMATION
2.2.1 MAIN MI-COM (CPU) PIN FUNCTION
Pin
No. Pin name I/O Function Pin
No. Pin name I/O Function
1 REMOCON I Remote control 22 PROTECT I Low B protect detection [Detect: H]
2 SDA2 I/O Data for Inter IC control (For main memory) 23 P_ON/OFF I Main power control [ON : H]
3 SCL2 O Clock for Inter IC contorl (For main memory) 24 LOCK - Not used
4 BUS_FREE - Not used 25 3.58/OTH - Not used
5 NC - Not used 26 4.5/OTH - Not used
6 KEY1 I Key scan for front key (Menu CH -/+) 27 H_SYNC I Horizontal sync
7 KEY2 I Key scan for front key (Vol -/+) 28 I/II - Not used
8 ECO IN - Not used 29 OSD_Ys O Ys (blanking) for OSD
9 AFT I AFT voltage for tuner 30 OSD_B O Blue for OSD
10 LED[POW] - Not used 31 OSD_G O Green for OSD
11 LED[TIM] O Liting for timer [Liting : H] 32 OSD_R O Red for OSD
12 GND - GND 33 NC - Not used
13 NC - Not used 34 RST I CPU reset [Reset:L]
14 NC - Not used 35 V_SYNC I Vertical sync
15 TV/V - Not used 36 TCLOCK - Not used
16 TEXT RESET - Not used 37 SDA1 I/O Data for Inter IC control (For generally)
17 ACL ON/OFF - Not used 38 SCL1 O Clock for Inter IC contorl (For generally)
18 VOL O Volume control 39 VDD I 3.3V
19 A_MUTE O Aodio muting [Muting : H] 40 OSC1 I System clock oscillation (4MHz)
20 NC - Not used 41 OSC2 O System clock oscillation (4MHz)
21 TEXT/OTH - Not used 42 VSS - GND

(No.YA392)1-5
SECTION 3
DISASSEMBLY
3.1 DISASSEMBLY PROCEDURE
3.1.1 REMOVING THE REAR COVER
• Unplug the power cord.
(1) Remove the 4 screws [A], 1 screw [B] and 1 screw [C] 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.
• Remove the MAIN PW BOARD.
(1) Raise the SPEAKER HOLDER claw [D] slightly, and
remove the SPEAKER HOLDER.
(2) Remove the SPEAKER.
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.
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.