SERVICE MANUAL
AV-21L81B
AV-25L81B
COLOUR TELEVISION
BASIC CHASSIS
CH
No. 51903
Sep. 2001
COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.
AV-21L81B (-VT)
AV-25L81B (-VT)
RM-C356-1C
RM-C356 REMOTE CONTROL UNIT
DISPLAY
SUPER
BASS
MENU
POWER
CHANNEL
VOLUME
SYSTEM
COLOUR
OFF TIMER
TV/VIDEO
PICTURE MODE
CHANNEL SCAN
ECO SENSOR
SOUND
MUTING
RETURN
123
456
78
0
9
-/--
CONTENTS
a SPECIFICATIONS ....................................................................................................................................2
a SAFETY PRECAUTIONS ........................................................................................................................3
a FEATURES ..............................................................................................................................................4
a FUNCTIONS .............................................................................................................................................5
a SPECIFIC SERVICE INSTRUCTIONS ....................................................................................................6
¤ OPERATING INSTRUCTIONS (APPENDIX) ....................................................................................... 1-1
a SERVICE ADJUSTMENTS ....................................................................................................................14
¤ STANDARD CIRCUIT DIAGRAM (APPENDIX) .................................................................................. 2-1
a PARTS LIST ...........................................................................................................................................39
2
No. 51903
AV-21L81B
AV-25L81B
Dimensions (W
× H × D)
59.8cm
× 47.43cm × 47.15cm
68.2cm
× 54.33cm × 47.75cm
Mass
22kg
32kg
TV RF System
B, G, D, K, M
Colour System
TV Mode
PAL / SECAM / NTSC3.58 / NTSC4.43
VIDEO Mode
PAL / SECAM / NTSC3.58 / NTSC4.43
Stereo System
Playback Only
Receiving Frequency
VHF (VL)
43.75MHz 142.25MHz
VHF (VH)
142.28MHz 428.75MHz
UHF
428.78MHz 865.75MHz
CATV
G Cable TVs of Mid (X-Z, S1-S10)
Super (S11-S20) & Hyper (S21-S41) bands receivable
Intermediate
VIF Carrier
38.0MHz
Frequency
31.5MHz (6.5MHz)
SIF Carrier
32.5MHz (5.5MHz)
33.5MHz (4.5MHz)
Colour Sub Carrier Frequency
PAL (4.43MHz), SECAM (4.40625MHz / 4.25MHz)
NTSC (3.58MHz / 4.43MHz)
Aerial Input Terminal
75Ø Unbalanced
Power Input
AC110 240V, 50 / 60Hz
Power Consumption
141W (Max.) / 88W (Avg.)
169W (Max.) / 106W (Avg.)
Picture Tube (Vsible size)
51cm measured diagonally
60cm measured diagonally
High Voltage (at cut-off in service mode)
29kV ± 1kV
31kV ± 1kV
Speaker
MAIN : 5
× 12cm
Oval type
×2, 7W +7W
BASS BLASTER UNIT :
13cm, 13W
Video / Audio Input (1 / 2 / 3)
Video(1,3)
: 1Vp-p, 75Ø (RCA pin jack)
Audio(1,2,3) : 500mVrms ( -4dBs ), High Impedance (RCA pin jack)
Component Input ( Input 2 )
Y
: 1Vp-p positive (negative sync provided, when terminated with 75Ø)
CB/CR
: 0.7Vp-p 75Ø
Video/Audio Output
1Vp-p, 75Ø (RCA pin jack)
500mVrms(-4dBs)
Low impedance (400Hz when modulated 100%) (RCA pin jack)
Headphone Jack
Stereo mini jack (3.5
)
Remote Control Unit
RM-C356-1C
(Battery size: AA/R06/UM-3
× 2)
SPECIFICATIONS
Items
Design & specifications are subject to change without notice.
Contents
AV-21L81B-VT
AV-25L81B-VT
AV-21L81B
AV-25L81B
No. 51903
3
SAFETY PRECAUTIONS
1. The design of this product contains special hardware, many circuits
and components specially for safety purposes. For continued pro-
tection, 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 manufactur-
er's warranty and will further relieve the manufacturer of responsi-
bility 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 (NEU-
TRAL) side ground or EARTH side ground when repairing.
Some model's power circuit is partly different in the GND. The differ-
ence of the GND is shown by the LIVE : (
) side GND, the ISO-
LATED (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 with a measur-
ing apparatus (oscilloscope etc.) the LIVE side GND and ISOLATED
(NEUTRAL) side GND or EARTH side GND at the same time.
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 dam-
age, 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 10kØ 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 com-
ponents 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.
(1) 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.
(2) 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.).
G 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 hav-
ing 1000 ohms per volt or more sensitivity in the following manner.
Connect a 1500Ø 10W resistor paralleled by a 0.15µF AC-type ca-
pacitor between an exposed metal part and a known good earth
ground (water pipe, etc.). Measure the AC voltage across the resis-
tor with the AC voltmeter. Move the resistor connection to each ex-
posed metal part, particularly any exposed metal part having a re-
turn 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
µF AC-TYPE
GOOD EARTH GROUND
4
No. 51903
AV-21L81B
AV-25L81B
FEATURES
s New chassis design enables use of an interactive on-screen control.
s Pure flat CRT produces fine textured picture in every detail.
s Wide range voltage (110V ~ 240V) for AC power input.
s With AUDIO/VIDEO/COMPONENT input terminals.
s I 2 C bus control utilizes single chip ICs.
s Built-in bass blaster circuit reinforces bass sound.
s By means of AUTO PROGRAM, the TV stations can be selected
automatically and the TV channels can also be rearranged auto-
matically.
s Built-in DIGITAL ECO MODE (ECONOMY, ECOLOGY).
In accordance with the brightness in a room, the brightness and/or
contrast of the picture can be adjusted automatically to make the op-
timum picture which is easy on the eye.
s Built-in OFF TIMER & RETURN +.
AV-21L81B
AV-25L81B
No. 51903
5
FUNCTIONS
a REAR PANEL
a FRONT PANEL
a REMOTE CONTROL UNIT
RM-C356-1C
RM-C356 REMOTE CONTROL UNIT
DISPLAY
SUPER
BASS
MENU
POWER
CHANNEL
VOLUME
SYSTEM
COLOUR
OFF TIMER
TV/VIDEO
PICTURE MODE
CHANNEL SCAN
ECO SENSOR
SOUND
MUTING
RETURN
123
456
78
0
9
-/--
VIDEO-1
INPUT
OUTPUT
COMPONENT
(VIDEO-2)
INPUT
BASS
SPEAKER
OUT
RR
R
CR
V
MONO
L/
V
Y/
V
L
MONO
L/
CB