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AV225T

service manual
Catalog

Chapter One About Maintenance 1
1.1 Safety precautions 1
1.1.1 Power supply 1
1.1.2 Precautions for antistatic 1
1.1.3 About placement position 2
1.2 Maintenance method 2
1.2.1 Visualized method 2
1.2.2 Electric resistance method 2
1.2.4 Current method 2
1.2.5 Cutting method 2
1.2.4Currentmethod 2
1.2.5Cuttingmethod 2
1.2.6 Element substitution method 3
1.2.7 Comparison method 3
1.3 Required device for maintenance 3

Chapter Two Operation Instructions 4
2.1 Control button locations and explanations 4
2.1.1 Front panel illustratlons 5
2.1.2 Rear panel illustration 5
2.1.3 illustrations to the 5
2.2 Basic operations remote control 6
2.2.1 Turn on/off this unit 6
2.2.2 O tp function 6
2.2.3 Select Input Sound Source 7
2.2.4 Bass Enhancer 7
2.2.5 Select Sound Field 8
2.2.6 Adjust Volume 9
2.2.7 Adjust Level 9
2.2.8 EQ function 10
2.2.9 Parameter Processing 11
2.2.10 Adjust Karaoke 12
2.2.11 Tuning Function 13
2.2.12 Other Operations 15

Chapter Three Principle and Servicing 17
Section One Principle of the Player 17
3.1.1 Composition of the player 17
3.1.2 Function and features 17
3.1.3 Player block diagram 18
3.1.4 The player signal flow chart 19
Section Two Unit Circuit Principle 20
3.2.1 Volume board circuit 20
3.2.2 Signal processing board circuit 23
3.2.3 MCU board circuit 25
3.2.4 Control panel circuit 29
3.2.5 Power board circuit 30
3.2.6 Power amplifier board and protection circuit 31
3.2.7 MIC, headphone board 34
3.2.8 Video in/out board circuit 34
Section Three Servicing Cases 36
3.3.1 Servicing instances 36
3.3.2 Troubleshooting process 41
Section Four Servicing Parameters 49
3.4.1 Signal waveform diagram 49
3.4.2 Key point voltage 56
Section Five Function Introduction to IC 57
3.5.1 function introduction to 4558 57
3.5.2 function introduction to Pt2399 58
3.5.3 function introduction to Cd4051 59
3.5.4 function introduction to Cd4052 60
3.5.5 function introduction to Cd4053 61
3.5.6 function introduction to Sm79164 62
3.5.7 function introduction to Pt2308 65
3.5.8 function introduction to Pt2222 66
3.5.9 function introduction to Lm1875 67
3.5.10 function introduction to TDA7265 68
3.5.11 function introduction to M62446 69
3.5.12 function introduction to AT24C02 70
3.5.13 function introduction to L7805 71
3.5.14 function introduction to 7812 72
3.5.15 function introduction to 7912 72
3.5.16 function introduction to LM324 73
3.5.17 function introduction to Pt2315 74
3.5.18 function introduction to 74VHC245 75
3.5.19 function introduction to Cd4094 77

Chapter Four Disassembly and Assembly Process 79
Chapter Cinque PCB board & Circuit diagram 87
Section One PCB board 87
Section Two circuit diagram 96

Chart 6 BOM List 105
6.1 Volume board 105
6.2 Volume board ai segment 105
6.3 Signal disposal board 106
6.4 Signal disposal board ai segment 108
6.5 C pu board 110
6.6 C pu board-smd 111
6.7 A mplifier board 112
6.8 Surface control board 116
6.9 Video input output board 117
6.10 Microphone holder board 117
6.11 Power board 118
6.12 R emote coneroller 120
6.13 P anel units 120
6.14 S ofeware program 121
6.15 S n lasel 121
6.16 Supplement module 121
Chapter One About Maintenance

1.1 Safety precautions
1.1.1 Power supply
When servicing audio power amplifier, the servicing personnel pay special attention to the power
board with 220V AC, or else the improper operation will lead to body damage. The alternate current
which outputs to power amplifier board through power board is also up to voltage with about 50V; when
servicing, short-circuit and joint welding cannot occur, or else the elements will be burnt out and trouble
range will be enlarged.

1.1.2 Precautions for antistatic
Movement and friction will both bring static electricity which causes serious damages to integrated
IC. Though static charge is little, when a limited quantity of electric charge is added to large-
scaleintegrated IC, as the capacitance is very small in the meantime, now the integrated IC is very much
easy to be struck through by static electricity or the performance will decrease. Thus static electricity
prevention is of extraordinary importance. The following are several measures to prevent static
electricity:
1. Use a piece of electric conduction metal with the length of about 2 metres to insert into the earth,
and Fetch the lead wire from the top of the surplus metal and connect to the required static electricity
device. The length and depth of the metal embedded under the earth should be determined according to
the wettability of the local soil. For humid places, it may be shorter, and longer and deeper for dry places.
If possible, it can be distributed and layed in terms of "
#"shape.
2. On operating table-board, the antistatic table cushion should be covered and grounded.
3. All devices and equipments should be placed on the antistatic table cushion and grounded.
4. Maintenance personnel should wear antistatic wrist ring which should be grounded.
5. Places around the operating position should also be covered with electric conduction cushion or
Painted with antistatic paint.

-1-
1.1.3 About placement position
1. Audio power amplifier cannot be installed in places with high temperature and humidity.
2. Positions for placement should be stable and secure.

1.2 Maintenance method
1.2.1 Visualized method
Directly view whether abnormalities of collision, lack of element, joint welding, shedding welding,
rosin joint, copper foil turning up, lead wire disconnection and elements burning up among pins of
elements appear. Check power supply of the machine and then use hands to touch the casing of part of
elements and check whether they are hot to judge the trouble spot. You should pay more attention when
using this method to check in high voltage parts.

1.2.2 Electric resistance method
Set the multimeter in resistance position and test whether the numerical value of resistance of each
point in the circuit has difference from the normal value to judge the trouble spot. But in the circuit the
tested numerical value of resistance is not accurate, and the tested numerical value of integrated IC's
pins can only be used for reference, so the elements should be broken down for test.

1.2.3 Voltage method
Voltage method is relatively convenient, quick and accurate. Set the multimeter in voltage position
and test power supply voltage of the player and voltage of a certain point to judge the trouble spot
according to the tested voltage variation.

1.2.4 Current method
Set the multimeter in current position and test current of the player of a certain point to judge the
trouble spot. But when testing in current method, the multimeter should be series connected in the
circuit, which makes this method too trivial and troublesome, so it is less frequently used in reality.

1.2.5 Cutting method
Cutting method should be combined with electric resistance method and voltage method to use.
This method is mainly used in phenomena of short circuit and current leakage of the circuit. When
cutting the input terminal voltage of a certain level, if voltage of the player rises again, it means that the
trouble lies in this level.

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1.2.6 Element substitution method
When some elements cannot be judged good or bad, substitution method may de adopted directly.

1.2.7 Comparison method
A same good PC board is usually used to test the correct voltage and waveform. Compared these
data with those tested through fault PC board, the cause of troubles may be found.
Through the above maintenance method, theoretical knowledge and maintenance experience, all
difficulties and troubles will be readily solved.

1.3 Required device for maintenance
бЇ Generator
Audio
б Digital oscillograph (Ї100MHE) б ▌
бЇ rework station
SMD
бЇMultimeter
бЇSoldering iron
бЇPointed-month pincers
бЇCutting nippers
бЇForceps
бЇElectric screw driver
бЇTerminals connecting cord
бЇHeadphone
бЇMicrophone

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Chapter Two Operation Instructions

2.1 CONTROL BUTTON LOCATIONS AND EXPLANATIONS
2.1.1 FRONT PANEL ILLUSTRATLONS

1 POWER SWITCH 9 Tuning
Power on/off this unit Select other frequency radio stations
2 LCD Screen downwards
Buttons operation indication and spectrum 10 BAND

display when working Select FM/AM tuner BAND
3 IR sensor 11 PRESET

Receive the infrared signals transmitted from Select the latter preset radio station
the remote control 12 PRESET

4 MASTER VOLUME- Select the previous preset radio station
Press this button to synchronously lower all 13 MODE

6CH volumes Select tuner mode:manual/auto
5 INPUT 14 MASTER VOLUME+

Sound source input button Press this button to synchronously increase
6 MIC VOLUME+ all 6CH volumes
Press this button to increase the volume of 15 STANDBY

MIC Standby
7 MIC VOLUME- 16 COVER OF PHONE JACK AND

Press this button to lower the volume of MIC MICROPHONE JACK
8 TUNING
Select other frequency radio stations upwards

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2.1.2 REAR PANEL ILLUSTRATION

1 AC-3/DTS 5.1CH INPUT
5.1CH audio signals input terminals that
connect to DVD, AC-3/DTS
2 AM/FM antenna terminal
Connect AM/FM antenna outside
3 Stereo Audio jack
The terminals that connect with VCD, DVD
stereo audio signals input
4 Video input
The terminals that connect with VCD,DVD
Video signals input
5 Video output jack
The terminals that connect with TV Video
signal output
6 Data
The data plate of this unit
7 SERIAL NO. Mark
The manufacturing records
8 CAUTION mark
Remind the user of dangerous voltage inside
9 Line-out
Subwoofer signals line-out jack
10 This unit's manufacturer
11 Terminals
Connect with SPEAKER terminals
12 Number buttons 1~8: Select 8 preset working modes
with the help of SAVE/CALL button, capable of storing
2.1.3 ILLUSTRATIONS TO THE and calling the user-set working mode parameters
13 SPEAKERS button: Adjust the separate channel level
REMOTE CONTROL with the help of / keys
14 CHILD LOCK button: Lock the functions of the front
1 STANDBY button: Power on, STANDBY switch button panel controls
2 DISPLAY button: Select audio spectrum display modes 15 SURR. Button: Select the surround sound field
3 MUTE button: Mute On/Off button
16 DEFAULT button: Restore the factory default settings
4 INPUT button: Select input signal sources manually
17 SAVE button: Store the current working mode
5 MOVIE button: OTP button to set standard movie parameters with the help of number buttons 1~8
theater surround mode 18 CALL button: Call the user-stored working mode
6 MUSIC button: OTP button to set standard concert mode parameters with the help of number buttons 1~8
7 K.R.OK: OTP button to set standard Karaoke mode 19 EQ select button: Select the equalization frequency
8 HI-FI button: Select the Hi-Fi sound field 20 MULTI-BAND EQ button:Adjust multi-band electronic
9 STANDARD button: Select the standard sound field equalization
10 CYBER LOGIC button: Select the cyber logic sound 21 Adjust button: Adjust level and multi-band EQ
field 22 EQ button: Circularly call the preset EQ modes
11 BASS ENHANCER button: Select the bass enhancing 23 AUTO EQ button: Analyze the current signal spectrum,
effect automatically set EQ parameters

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24 VOLUME button: Adjust the karaoke level with / keys The signal automatically, press the INPUT button
25 ECHO button: Adjust the karaoke ECHO with / keys
26 VOICE MODIFY: on the remote control to select the input signal.
MODIFY button: Select Karaoke voice modify When the unit is in normal working mode,
WF button: Karaoke wide sound field On/Off
27 TONE button: Adjust the karaoke BASS/Treble tone press the STANDBY button on the front panel or
levelwith / keys remote control if you want to enter standby mode.
28 DELAY button: Adjust the karaoke delay time with /
Please turn off the power when you are not
keys
29 MASTER VOL button: Synchronously increase/decrease going to use the unit for a long time.
6 channels' volume
30 BAND button: Select FM/AM tuner band Please turn off the power every time after you
31 MODE button: Select tuner mode:manual/auto use the unit.
32 STEP button: Select AM tuning step:9K/10K
33 MEMORY button: Memory the received radio station Press the " POWER" button on the front
with the help of number buttons 0~9
34 CLEAR button: Clear the preset radio station with the panel to power off this unit.
help of number buttons 0~9
35 TUNING : Scan other frequency radio station upwards
36 TUNING : Scan other frequency radio station
downwards
37 PRESET : Select the latter preset radio station
38 PRESET : Select the previous preset radio station
39 NUMBER 0~9 :Save the received radio station programs
or directly call the preset programs with the help of
MEMORY button

2.2 BASIC OPERATIONS
POWER

2.2.1 TURN ON/OFF THIS UNIT
Please check the connection cords before
turning this unit on. If all connections are correct,
you can connect this unit to power.
Press the POWER button, this unit enters the
standby mode .
When this unit is in the standby mode, it
detects the input signals automatically.
When there is signal input, this unit turns on
automatically.
When the input signal is too small, this unit
might not detect the signal and will not turn on
automatically.
When there is signal input and the unit cannot
turn on automatically, press the STANDBY
button on the front panel or remote control to
operate manually and select input signals by
2.2.2 OTP function
using the INPUT button.
When the unit is in the standby mode, press We have set the OTP function to simplify the
the STANDBY button on the front panel or
operation of testing sound effects.If the played
remote control to turn on this unit.
Press the STANDBY button on the front panel disc is movie or story, you just press the MOVIE
or remote control. button and the system will automatically set
After turning on this unit, it detects the input
signal automatically. When there is signal input, standard movie mode.If the played disc is music,
it receives the input signal automatically. you just press the MUSIC button and the system
Otherwise, the unit will automatically search
will automatically set standard music mode.If
signals all the time.
When there is signal input but it cannot receive you want to sing Karaoke, you just press the

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K.R.OK button after inserting microphone and 2.2.3 Select Input Sound Source
The system will automatically set standard This unit utilizes two input lines of stereo audio
Karaoke mode. sources: VCD, DVD; one line 5.1 channel signal
Press the MOVIE button to set standard input. Select the input signal source manually
theater surround mode. through the remote control.
Automatically detect the input signal source. If Press the INPUT button on the remote control,
many signal sources input, it will select the and "INPUT TUNER" splays, which means
current signal input preferentially. TUNER has been selected.
Automatically set the parameters of surround. Press the INPUT button on the remote control,
If 5.1CH input signal is detected, it will and "INPUT VCD" displays, which means VCD
automatically adopt standard mode; if 2CH 2CH input jack has been selected.
signal source is detected, it will automatically Press the INPUT button on the remote control,
adopt Cyber Logic. and "INPUT DVD" displays, which means DVD
Press the MUSIC button to set standard music 2CH input jack has been selected.
modeAutomatically detect the input signalsource. Press the INPUT button on the remote control,
If many signal sources input, it will select the and "INPUT 5.1CH" displays, which means
current signal preferentially. 5.1CH input jack has been selected.
Automatically set the parameters when
enjoying music. If 5.1CH input signal is detected,
it will automatically adopt standard mode;if 2CH
signal source is detected, it will automatically
adopt Hi-Fi mode.
Press the K.R.OK button to set standard
Karaoke mode.
Automatically detect the input signal source. If
many signal sources input, it will select the
current signal preferentially.
Automatically set the parameters of Karaoke
mode.
NOTE: If the signal is too weak or in the blank
segment of music
when operating, the system will probably appear
wrong indications.

2.2.4 Bass Enhancer
In order to strengthen the low frequency of music,
you may start up Bass Enhancer function.
Press the "BASS ENHANCER" button on the
front panel or remote control, "BASS driver 0",
"BASS driver 1 ", "BASS driver 2 " or"BASSdriver
3" will display.

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The display "BASS driver 1-3" means the first, Press the STANDARD button on the remote
second and third Bass Enhancer; the subwoofer control and "STANDARD" will display, which
signal adds into the master channelsignal; turn means the system enters standard sound field.
off the subwoofer line output.
The display "BASS driver 0 " means turn off
Bass Enhancer; normal subwoofer line output.
Bass Enhancer function cannot be started up
in Hi-Fi mode.

3 Cyber Logic
In order to make 2 channel input signals have
multi-channel sound field effect, you may select
Cyber Logic sound field.
2.2.5 Select Sound Field Press the CYBER LOGIC button on the remote
1 HI-FI
control and "CYBER LOGIC" will display, which
In 2CH signal input, you may select the Hi-Fi
means the system enters Cyber Logic sound
mode to keep the originally musical features.
field: if "INVALID" displays, it means the system
Press the HI-FI button on the remote control
cannot enter Cyber Logic
and "HI-FI" will displays, which means the Cyber Logic mode is invalid in 5.1 channel
system enters the Hi-Fi mode; if "NVALID" signal input.
displays, it means the system cannot enter the
Hi-Fi mode.
Bass Enhancer function and operations
related to EQ are invalid in Hi-Fi mode.
Pressing the HI-FI button is invalid in
5.1channel input.

4 Surround
In order to cater for different listening
Environments and meet different sound effect
requirements of customers, you may select
different surround modes in 5.1 channel signal
input status.
2 Standard Press the SURR button on the remote control
In order to keep the correspondence with input in 5.1 channel signal source input, the surround
signals and adjust output timbre according to will display.
personal habit, you may select the standard Press the SURR button on the remote control
sound field. Repeatedly; you may select the environment

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Modes between Affectional movie, Sowordsmen 2.2.7 Adjust Level
movie, Gunfignt movie, Sci-fi movie and music. 1 Left channel level
The environment surround is invalid in 2- When sound of left and right channels is
channel signal input status. imbalance, you may adjust R channel level to
The environment surround is invalid if make it in balance with L channel.
microphone is inserted. Press the SPEAKERS button on the remote
control and "L: 00" will display. Operate as
follows:
Press the " " button on the remote control to
Increase the volume of L channel. The max level
is +60.Press the " " button on the remote
control to decrease the volume of L channel. The
min level is -60.
2 Right channel level
When sound of left and right channels is
imbalance, you may adjust L channel level to
make it in balance with R channel.
Press the SPEAKERS button on the remote
control and "L: 00" will display. Operate as
2.2.6 Adjust Volume follows:
Press the " " button on the remote control to
1 Master Volume
Increase the volume of L channel. The max level
When the current sound is too high, too low or
is +60.Press the " " button on the remote
unsuitable, you may press the MASTER VOL on
control to decrease the volume of L channel. The
the front panel or remote control to adjust the
min level is -60.
volume of all channels.
3 Center level
Press the "+" button of master volume on the
When sound of left and right channels is
front panel or remote control to increase all
imbalance, you may adjust R channel level to
channels' volume simultaneously; the max
make it in balance with L channel.
volume is 60.
Press the SPEAKERS button on the remote
Press the "-" button of master volume on the
control and "R: 00" will display. Operate as
front panel or remote control to decrease all
follows:
channels' volume simultaneously; the min
Press the " " button on the remote control to
volume is 0.
increase the volume of R channel. The max level
The master volume displays as the example:
is +60.Press the " " button on the remote
"VOL: 20"
control to decrease the volume of R channel.
The min level is -60.
4 Surround Left level
When sound of center channel is unsuitable,
you may adjust center level to make it suitable to
the sound field.
Press the SPEAKERS button on the remote
control and "C: 00" will display. Operate as
follows:
Press the " " button on the remote control to
increase the volume of C channel. The max level
is +60.Press the " " button on the remote
control to decrease the volume of C channel.
The min level is -60.
NOTE: The center level cannot be adjusted only
when left and right channels have output.
5 Surround Right level
When sound of surround left is unsuitable, you

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may adjust surround left level to make it suitable Press the " " button on the remote control to
to the sound field. increase the volume of subwoofer. The max level
Press the SPEAKERS button on the remote is +60.
control and "SL: 00" will display. Operate as Press the " " button on the remote control to
follows: decrease the volume of subwoofer. The min level
Press the " " button on the remote control to is -60.
increase the volume of surround left. The max NOTE: The subwoofer level cannot be adjusted
level is +60.Press the " " button on the remote only in Hi-Fi and Bass Enhancer conditions.
control to decrease the volume of surround left.
The min level is -60. 2.2.8 EQ function
NOTE: The surround left level cannot Due to the personal like to music, you may adjust
beadjusted only when left and right channels EQ to meet your own needs. If the music tempo
have output. is not enough or full, adjust bass; if the voice is
When sound of surround right is unsuitable, unclear, adjust middle frequency; if the
you may adjust surround right level to make it musical details are not rich, adjust treble.
suitable to the sound field. 1 Pre-set EQ
When the sound of master volume is too weak
Press the SPEAKERS button on the remote
or unclear, you may directly use pre-set EQ
control and "SR: 00" will display. Operate as
mode to make it accordant with the current music.
follows:
Press the " " button on the remote control to This unit utilizes 8 EQ modes: Rock, Jazz,
increase the volume of surround right. The max Classical, Pop, Disco, Rap and Blues.
level is +60.Press the " " button on the remote Press the EQ button on the remote control to
control to decrease the volume of surround right. display the EQ curve.
The min level is -60. Press the EQ button repeatedly to select the
NOTE: The surround right level cannot be EQ mode accordant with the current music.
adjusted only when left and right channels have EQ mode cannot be adjusted in Hi-Fi mode.
2 Multi-band EQ
output. When the sound of master volume is too weak
6 Subwoofer level or unclear, you may set EQ mode yourself to
When sound of subwoofer is unsuitable, you meet you own taste.
may adjust the volume of subwoofer speaker Press the "AUTO EQ" button on the remote
and the level of subwoofer channel to make it control to display the current EQ curve. There is
balanced to the sound field. a cursor flashing in the current frequency.
Press the SPEAKERS button on the remote
Press the " " button on the remote control to
control and "SW: 00" will display. Operate as
select the high
follows:
frequency. The flashing cursor moves rightwards
until the rightmost.
Press the " " button on the remote control to
select the low frequency. The flashing cursor
moves leftwards until the leftmost.
Press the " " button on the remote control and
the current frequency level increases until the
maximum.
Press the " " button on the remote control and
the current frequency level decreases until the
minimum.
EQ mode cannot be adjusted in Hi-Fi mode.
3 Auto EQ
When the sound of master volume is
unsuitable to you listening, you may select auto
EQ.
The unit will automatically analyze the current
spectrum to set the current EQ according to the
current music.

- 10 -
Press the AUTO EQ button on the remote channel level is too high or too low, the system
control to display the analyzing curve.
EQ function will adjust automatically
Auto EQ setup is invalid in Hi-Fi mode.

2.2.9 Parameter Processing
To memory the current parameter for later use,
or use the defauly parameter, the Memory and
Call functions will be used. The current
parameters to be adjusted include: Channel
Level, EQ, Bass Enhancer, Sound Field,
Environment Surround, MIC Volume, MIC Treble,
MIC Bass, MIC Delay, MIC Echo and Voice
Modification.
1 Call Default parameter
Press the number buttons 1-8 on the remote
control and "CALL 1-8" displays.
Setup will be processed automatically
according to the default parameters.
2 Memory Parameters
Press the "SAVE" button on the remote control
first to display "SAVE "
Press the number buttons 1-8 on the remote
control again under the display "SAVE "
The current parameter is memorized into the
corresponding number buttons and "SAVE 1-8"
displays.
3 Call parameters
Press the "CALL" button on the remote control
first to display "CALL "
Press the number buttons 1-8 on the remote
control again under the display "CALL "
The parameters memorized in the number
buttons before will be adopted currently and
"CALL 1-8" displays.NOTE: Due to some
unexpected reasons, the user-memorized
parameters will probably be lost, so please
adjust again and then memorize. The system will
automatically check the parameter saved ast
time when switching on this unit. When the

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2.2.10 Adjust Karaoke
1 Microphone Volume
When inserting microphones to sing Karaoke,
press the MIC VOL button to adjust the volume
of microphonewhen the microphone voice is too
high, too low or unsuitable.
Press the " " button of MIC VOL on the front
panel to increase the volume of microphone
The maximum volume is 30.
Press the " " button of MIC VOL on the front
panel to decrease the volume of microphone
The minimum volume is 0.
Press the "VOLUME" on remote control,then
press " "" " to adjust karaoke volume.
The microphone volume displays as "MIC VOL
20".
The microphone volume cannot be adjusted
when not inserting microphones.
2 Bass
When inserting microphone to sing Karaoke, you
may adjust microphone bass when the sound
tempo is not full or rich.
Press the "TONE" button on the remote control
once then press" " or " " to adjust the bass of
microphone. The adjustable range is 6.
The microphone bass displays as "MIC BASS
+2"
The microphone bass cannot be adjusted
when not inserting microphone. 4 Echo
3 Treble When inserting microphone to sing Karaoke, you
When inserting microphone to sing Karaoke, you may adjust microphone echo when the sound is
may adjust microphone treble when the sound is weak or not full.
unclear. Press the "ECHO" button on the remote
Press the "TONE" button on the remote control then press " " or" " to adjust the echo of
control twice, then press " " or " " to adjust microphone. The adjustable range is 0~7.
the treble of microphone. The adjustable range The microphone echo displays as "MIC ECHO
is 6 2"
The microphone treble displays as "MIC The microphone echo cannot be adjusted
TREBL+2" when not inserting microphone.
The microphone treble cannot be adjusted
when not inserting microphone.

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5 Delay 7 Wide Field
When inserting microphone to sing Karaoke, you When inserting microphone to sing Karaoke, you
may adjust microphone delay when the sound is may select to switch on/off Karaoke wide field
not full. when the sound field is not wide.
Press the "DELAY" button on the remote Press the "WF" button on the remote control to
control then press " " of " " to adjust the delay display "MIC WIDE ON", which means Karaoke
of microphone. The adjustable range is 0~7.. Wide Sound Field is switched on.
The microphone delay displays as "MIC Press the "WF" button on the remote control
DELAY 2" again to display "MIC WIDE OFF", which means
The microphone delay cannot be adjusted Karaoke Wide Sound Field is switched off.
when not inserting microphone. The karaoke WF button cannot be selected
when not inserting microphone.
NOTE: If noise appears when adjusting Karaoke,
please refer to TROUBLESHOOTING for details.

6 Modify
When inserting microphone to sing Karaoke, you
may select microphone euphonize mode when 2.2.11 Tuning Function
Auto Tuning One:
the sound is unsuitable.
Pressing the "MODIFY" button on the remote 1 Press INPUT button on the front panel or
control can circularly select the euphonized remote control to select TUNER as the input
бя
voice"NATURAL", "Full", "Fruity", "Bright" and sound source.
"Ringing".
The MODIFY button cannot be selected when
not inserting microphone.

2 Press BAND button on the front panel or
remote control to select receiving wave band.

7 Wide Field
When inserting microphone to sing Karaoke, you
may select to switch on/off Karaoke wide field when
the sound field is not wide.

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NOTE: 1. This operation will search and save
automatically, so the user-preset programs will
be covered.
2. Pressing TUNING / button may
stop the function in the course of this operation.
If the tuning searching stops in imperfect radio
station (because of weak radio station signals or
radio wave interferes), please change into
3 Press TUNING / button on the front panel manual tuning method.
or remote control for above 5 seconds to Clear Radio Station
automatically tune upwards/downwards until If you do not need the preset radio station, you
your needed radio station programs. When may clear it by using CLEAR button on the
programs are searched, it will stop searching remote control with the help of number buttons
automatically. 0~9.
1 Press CLEAR button on the remote control.
2 Press the serial number of the radio station
3бв
that you want to clear in the course of the
screen's displaying"CLEAR " to finish this
operation.

If the tuning searching stops in imperfect radio
station or radio wave interferes, please continue
operating.
If the tuning searching stops in imperfect radio
station (because of weak radio station signals),
please change into manual tuning method. NOTE: 1. This operation is beyond retrieve, so
4 The following save and call operations are please take care to operate.
the same with manual tuning operations. 2. If you clear the radio station
Auto Tuning Two: incautiously, you may save again according to
1 Firstly select TUNER as the current input
the select operation.
sound source according to the operations oF The Explanation of MODE button
"Manual Tuning", and then select the wave band This unit has two working modes in the receiving
to be received. status: AUTO/MANUAL
2 Press MEMORY button on the front panel or 1 In AUTO working mode, if you select FM
remote control, and then press TUNING / wave band, this unit will automatically recognize
button for above 0.5 seconds during the course the radio station program is mono signal or
of displaying MEMORY to enter the radio station stereo signal and keep the mono or stereo
auto searching status. receiving status.
2 If the received radio station program has
louder noise or cacophony in stereo status, you
may switch to MANUAL working mode.In this
way, the unit is in mono receiving status to
decrease noise and cacophony generally.
You may switch the two working modes through
MODE button on the remote control.

- 14 -
NOTE: 1. AM round antenna should be placed far
away from the equipment. You may put up on the
wall or on the bookshelf.
2. AM round antenna and outdoor antenna can
be used at the same time.
Connect to FM Antenna
Connect to the indoor FM antenna
Connect the accessional indoor FM antenna to
Antenna Connection 75 UNBAL.FM ANT terminal.
You may use our accessional AM and FM indoor
antenna when in bad receiving effect. Generally
speaking, these antennae can supply enough
signal strength.
Connect to AM Round Antenna
1 Push the jack button to open it.Push the jack
button to open it.
2 Connect the AM round antenna cord to AM
ANT and GND terminals.
3 Let go of the button to clamp the speaker
cord. Pull the cord lightly to check the connection
is right or not. NOTE:Do not use the outdoor and indoor FM
antennae at the same time.

How to Connect
GND (Grounding) terminal
Push the jack button to open it.
In order to ensure the safety and decrease the interference,
Insert the speaker cord. please well connect the GND terminal. The better grounding
method is insert the metal pole into wet ground.
Let go off the button to clamp
thespeaker cord.

2.2.12 Other Operations
4 Connect the AM round antenna to the stand.
1 Mute
AM round antenna Mute the sound to make your conversation or
answering telephone not be affected by music.
Press the MUTE button on the remote control
to mute the sound and the display "MUTE"
flickers.

5 Adjust the direction of AM round antenna
to get the best receiving effect.

Rotate

Mute

- 15 -
2 Child Lock The DISPLAY button cannot be selected when
To prevent the children wrongly pressing the no signals input.
front panel buttons, you may lock the buttons on
Other Operations
the front panel.
Press the CHILD LOCK button on the remote
control to display "LOCK". The buttons on the
front panel are invalid and now "LOCKED"
displays.
Press the CHILD LOCK button on the remote
control again to display"UNLOCK" and the fronta
pnel buttons can be normally used.

4 Default
When the system parameters adjusted disorderly,
you may restore the default settings.
Press the DEFAULT button on the remote
control to display "DEFAULT".
The unit automatically sets the default
parameters.
3 Display
To make the display spectrum colorful, we have
set many kinds of spectrum display means. You
may press the DISPLAY button to select.
After switching on the unit, it will automatically
select a kind of spectrum display mode every
third moment or so.
Pressing the DISPLAY button on the remote
control can cancel auto switch and select your
favorite display mode.
Pressing the DISPLAY button on the remote
control repeatedly can select many kinds of
Default
spectrum display effects until auto switch.

- 16 -
Chapter Three Principle and Servicing

Section One Principle of the Player

AV225T (RU) is an advanced power amplifier with complete functions. Based on the former power
amplifiers, it adopts LCD screen, with sky blue background matched with 16 different kinds of spectrum
display styles, in addition, this player is with tuning function and it is an excellent selection for users who
love listening to radio.

3.1.1 Composition of the player
1. Volume board: select input signal source, Cyber Logic and bass enhancer control.
2. Signal processing board: Karaoke signal processing and 5.1CH signal amplifying.
3. MCU board: player control, frequency point gating, and auto search circuit.
4. Control panel: LCD display, remote keyboard and background light display.
5. Power board: supply the working voltage required by each unit circuit and perform player
protection function.
6. Power amplifier board: perform power amplifying to 5.1CH analog signal.
7. Digital tuner: receive radio signal and then send to power amplifier for signal processing.
8. MIC, headphone board: MIC signal input, headphone amplifying output circuit.
9. Video input and output board: fulfil the switch of VCD, DVD channel.

3.1.2 Function and features
бЇBuilt-in 5CH power amplifying, applicable to AC-3/DTS and stereo music replay. Main channel
80W, central/surround 15W with strong power.
бЇ
AC-3/DTS, VCD, DVD input jack and subwoofer output jack.
бЇ volume control and separate level control, with 7-band electronic equalization.
6CH
бЇ enhancer system, Cyber logic function and Hi-Fi playback function.
Bass
бЇ
Q-play function of movie, music and Karaoke.
бЇ
Multiple EQ modes, applicable to different music styles.
бЇ spectrum analysis compensation function performs compensation to signals automatically.
Auto
бЇ
Complete Karaoke function, including separate MIC volume control, high/low tone adjustment,
voice compensation, delay and echo adjustment, Karaoke wide sound field function.

- 17 -
220V

XP7
SWM
Signal output XP13 XS13
RLY0
XS1 P_RC RLY
XL100 XS7 P_RC Video board
OVER XS101 Tuner socket
P_LRM
P_CSM
XP8 XP101
XP9 XS9
L2
SWM
Volume board
Power board R2
C2
L1
SL2 XS20
R1
XS22
SR2
XS8 VC+ C1
GND
GND SL1 XP20 XP22
VC- SR1
XS2 XS3 XS4
Xp101

Transformer
elementary Sublevel coil
D+5V
SWITCH DGND CPU board
L1
R1

XS25 XP100
XP23
XS23 XS6 XS102 XS103 XS12

+12V
GND
Sublevel coil -12V
+12V
GND
GND
-12V

Transformer
XP25 XP12 XP102 XP103

MIC holder
board
Control panel
A A

Input selection
TUNER(L/R) B B Power amplifier board

AGND
+12V
5.1CH

-12V
VCD(L/R) 1
VCD

CD4051
LR_T 2

Electronic volume
Headphone 3
DVD(L/R) L/R L/R DVD
amplif