BBK AV225T Service Manual

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AV225T

service manual

Catalog

Chapter One About Maintenance

1.1 Safety precautions

1.1.1 Power supply

1.1.2 Precautions for antistatic

1.1.3 About placement position

1.2 Maintenance method

1.2.1 Visualized method

1.2.2 Electric resistance method

1.2.4 Current method

1.2.5 Cutting method

1.2.4Currentmethod

1.2.5Cuttingmethod

1.2.6 Element substitution method

1.2.7 Comparison method

1.3 Required device for maintenance

Chapter Two Operation Instructions

2.1 Control button locations and explanations

2.1.1 Front panel illustratlons

2.1.2 Rear panel illustration

2.1.3 llustrations to the

2.2 asic operations remote control

2.2.1 urn on/off this unit

2.2.2 tp function

2.2.3 Select Input Sound Source

2.2.4 Bass Enhancer

2.2.5 Select Sound Field

2.2.6 Adjust Volume

2.2.7 Adjust Level

2.2.8 EQ function

2.2.9 Parameter Processing

2.2.10 Adjust Karaoke

2.2.11 Tuning Function

2.2.12 Other Operations

Chapter Three Principle and Servicing

Section One Principle of the Player

3.1.1 Composition of the player

3.1.2 Function and features

3.1.3 Player block diagram

3.1.4 The player signal flow chart

Section Two Unit Circuit Principle

3.2.1 Volume board circuit

3.2.2 Signal processing board circuit

3.2.3 MCU board circuit

3.2.4 Control panel circuit

3.2.5 Power board circuit

3.2.6 Power amplifier board and protection circuit

3.2.7 MIC, headphone board

3.2.8 Video in/out board circuit

Section Three Servicing Cases

3.3.1 Servicing instances

3.3.2 Troubleshooting process

Section Four Servicing Parameters

3.4.1 Signal waveform diagram

3.4.2 Key point voltage

Section Five Function Introduction to IC

3.5.1 function introduction to 4558

3.5.2 function introduction to Pt2399

3.5.3 function introduction to Cd4051

3.5.4 function introduction to Cd4052

3.5.5 function introduction to Cd4053

3.5.6 function introduction to Sm79164

3.5.7 function introduction to Pt2308

3.5.8 function introduction to Pt2222

3.5.9 function introduction to Lm1875

3.5.10 function introduction to TDA7265

3.5.11 function introduction to M62446

3.5.12 function introduction to AT24C02

3.5.13 function introduction to L7805

3.5.14 function introduction to 7812

3.5.15 function introduction to 7912

3.5.16 function introduction to LM324

3.5.17 function introduction to Pt2315

3.5.18 function introduction to 74VHC245

3.5.19 function introduction to Cd4094

Chapter Four Disassembly and Assembly Process

Chapter Cinque PCB board & Circuit diagram

Section One PCB board

Section Two circuit diagram

Chart 6 BOM List

6.1 olume board

6.2 olume board ai segment

6.3 ignal disposal board

6.4 ignal disposal board ai segment

6.5 pu board

6.6 pu board-smd

6.7 mplifier board

6.8 urface control board

6.9 ideo input output board

6.10 Microphone holder board

6.11 ower board

6.12 emote coneroller

6.13 anel units

6.14 ofeware program

105

106

108

110

111

112

116

117

118

120

121

6.15 n lasel

6.16 Supplement module

121

ChapterOneAboutMaintenance

1.1Safetyprecautions

1.1.1Powersupply

Whenservicingaudiopoweramplifier,theservicingpersonnelpayspecialattentiontothepower boardwith220VAC,orelsetheimproperoperationwillleadtobodydamage.Thealternatecurrent whichoutputstopoweramplifierboardthroughpowerboardisalsouptovoltagewithabout50V;when servicing,short-circuitandjointweldingcannotoccur,orelsetheelementswillbeburntoutandtrouble rangewillbeenlarged.

1.1.2Precautionsforantistatic

Movementandfrictionwillbothbringstaticelectricitywhichcausesseriousdamagestointegrated IC.Thoughstaticchargeislittle,whenalimitedquantityofelectricchargeisaddedtolargescaleintegratedIC,asthecapacitanceisverysmallinthemeantime,nowtheintegratedICisverymuch easytobestruckthroughbystaticelectricityortheperformancewilldecrease.Thusstaticelectricity preventionisofextraordinaryimportance.Thefollowingareseveralmeasurestopreventstatic electricity:

1.Useapieceofelectricconductionmetalwiththelengthofabout2metrestoinsertintotheearth, andFetchtheleadwirefromthetopofthesurplusmetalandconnecttotherequiredstaticelectricity device.Thelengthanddepthofthemetalembeddedundertheearthshouldbedeterminedaccordingto thewettabilityofthelocalsoil.Forhumidplaces,itmaybeshorter,andlongeranddeeperfordryplaces. Ifpossible,itcanbedistributedandlayedintermsof“#”shape.

2.Onoperatingtable-board,theantistatictablecushionshouldbecoveredandgrounded.

3.Alldevicesandequipmentsshouldbeplacedontheantistatictablecushionandgrounded.

4.Maintenancepersonnelshouldwearantistaticwristringwhichshouldbegrounded.

5.Placesaroundtheoperatingpositionshouldalsobecoveredwithelectricconductioncushionor Paintedwithantistaticpaint.

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1.1.3Aboutplacementposition

Audiopoweramplifiercannotbeinstalledinplaceswithhightemperatureandhumidity.

2.Positionsforplacementshouldbestableandsecure.

1.2Maintenancemethod

1.2.1Visualizedmethod

Directlyviewwhetherabnormalitiesofcollision,lackofelement,jointwelding,sheddingwelding, rosinjoint,copperfoilturningup,leadwiredisconnectionandelementsburningupamongpinsof elementsappear.Checkpowersupplyofthemachineandthenusehandstotouchthecasingofpartof elementsandcheckwhethertheyarehottojudgethetroublespot.Youshouldpaymoreattentionwhen usingthismethodtocheckinhighvoltageparts.

1.2.2Electricresistancemethod

Setthemultimeterinresistancepositionandtestwhetherthenumericalvalueofresistanceofeach pointinthecircuithasdifferencefromthenormalvaluetojudgethetroublespot.Butinthecircuitthe testednumericalvalueofresistanceisnotaccurate,andthetestednumericalvalueofintegratedIC's pinscanonlybeusedforreference,sotheelementsshouldbebrokendownfortest.

1.2.3Voltagemethod

Voltagemethodisrelativelyconvenient,quickandaccurate.Setthemultimeterinvoltageposition andtestpowersupplyvoltageoftheplayerandvoltageofacertainpointtojudgethetroublespot accordingtothetestedvoltagevariation.

1.2.4Currentmethod

Setthemultimeterincurrentpositionandtestcurrentoftheplayerofacertainpointtojudgethe troublespot.Butwhentestingincurrentmethod,themultimetershouldbeseriesconnectedinthe circuit,whichmakesthismethodtootrivialandtroublesome,soitislessfrequentlyusedinreality.

1.2.5Cuttingmethod

Cuttingmethodshouldbecombinedwithelectricresistancemethodandvoltagemethodtouse. Thismethodismainlyusedinphenomenaofshortcircuitandcurrentleakageofthecircuit.When cuttingtheinputterminalvoltageofacertainlevel,ifvoltageoftheplayerrisesagain,itmeansthatthe troubleliesinthislevel.

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1.2.6Elementsubstitutionmethod

Whensomeelementscannotbejudgedgoodorbad,substitutionmethodmaydeadopteddirectly.

1.2.7Comparisonmethod

AsamegoodPCboardisusuallyusedtotestthecorrectvoltageandwaveform.Comparedthese datawiththosetestedthroughfaultPCboard,thecauseoftroublesmaybefound.

Throughtheabovemaintenancemethod,theoreticalknowledgeandmaintenanceexperience,all difficultiesandtroubleswillbereadilysolved.

1.3Requireddeviceformaintenance

AudioGenerator

◆

Digitaloscillograph(100MHE)

◆≥

SMDreworkstation

◆

Multimeter

◆

Solderingiron

◆

Pointed-monthpincers

◆

Cuttingnippers

◆

Forceps

◆

Electricscrewdriver

◆

Terminalsconnectingcord

◆

Headphone

◆

Microphone

◆

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Chapter Two Operation Instructions

2.1 CONTROL BUTTON LOCATIONS AND EXPLANATIONS

2.1.1 FRONT PANEL ILLUSTRATLONS

POWER SWITCH Power on/off this unit

LCD Screen Buttons operation indication and spectrum display when working

IR sensor Receive the infrared signals transmitted from the remote control

MASTER VOLUMEPress this button to synchronously lower all 6CH volumes

INPUT Sound source input button

MIC VOLUME+ Press this button to increase the volume of MIC

MIC VOLUMEPress this button to lower the volume of MIC

TUNING Select other frequency radio stations upwards

Tuning Select other frequency radio stations downwards

BAND Select FM/AM tuner BAND

PRESET Select the latter preset radio station

PRESET Select the previous preset radio station

MODE Select tuner mode:manual/auto

MASTER VOLUME+ Press this button to synchronously increase all 6CH volumes

STANDBY Standby

COVER OF PHONE JACK AND MICROPHONE JACK

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2.1.2 REAR PANEL ILLUSTRATION

AC-3/DTS 5.1CH INPUT

5.1CH audio signals input terminals that connect to DVD, AC-3/DTS

AM/FM antenna terminal

Connect AM/FM antenna outside

Stereo Audio jack

The terminals that connect with VCD, DVD stereo audio signals input

Video input

The terminals that connect with VCD,DVD Video signals input

Video output jack

The terminals that connect with TV Video signal output

Data The data plate of this unit

SERIAL NO. Mark

The manufacturing records

CAUTION mark

Remind the user of dangerous voltage inside

Line-out

Subwoofer signals line-out jack

This unit's manufacturer

Terminals

Connect with SPEAKER terminals

2.1.3 ILLUSTRATIONS TO THE REMOTE CONTROL

STANDBY button: Power on, STANDBY switch button

DISPLAY button: Select audio spectrum display modes

MUTE button: Mute On/Off button INPUT button: Select input signal sources manually

MOVIE button: OTP button to set standard movie

theater surround mode

MUSIC button: OTP button to set standard concert mode

K.R.OK: OTP button to set standard Karaoke mode

HI-FI button: Select the Hi-Fi sound field

STANDARD button: Select the standard sound field

CYBER LOGIC button: Select the cyber logic sound field

BASS ENHANCER button: Select the bass enhancing effect

Number buttons 1~8: Select 8 preset working modes with the help of SAVE/CALL button, capable of storing and calling the user-set working mode parameters

SPEAKERS button: Adjust the separate channel level with the help of / keys

CHILD LOCK button: Lock the functions of the front panel controls

SURR. Button: Select the surround sound field

DEFAULT button: Restore the factory default settings

SAVE button: Store the current working mode parameters with the help of number buttons 1~8

CALL button: Call the user-stored working mode parameters with the help of number buttons 1~8

EQ select button: Select the equalization frequency

MULTI-BAND EQ button:Adjust multi-band electronic equalization

Adjust button: Adjust level and multi-band EQ

EQ button: Circularly call the preset EQ modes AUTO EQ button: Analyze the current signal spectrum,

automatically set EQ parameters

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VOLUME button: Adjust the karaoke level with / keys

ECHO button: Adjust the karaoke ECHO with / keys

VOICE MODIFY: MODIFY button: Select Karaoke voice modify WF button: Karaoke wide sound field On/Off

TONE button: Adjust the karaoke BASS/Treble tone levelwith / keys

DELAY button: Adjust the karaoke delay time with / keys

MASTER VOL button: Synchronously increase/decrease 6 channels' volume

BAND button: Select FM/AM tuner band

MODE button: Select tuner mode:manual/auto

STEP button: Select AM tuning step:9K/10K

MEMORY button: Memory the received radio station with the help of number buttons 0~9 CLEAR button: Clear the preset radio station with the

help of number buttons 0~9

TUNING : Scan other frequency radio station upwards

TUNING : Scan other frequency radio station downwards

PRESET : Select the latter preset radio station

PRESET : Select the previous preset radio station

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

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 using the INPUT button.

When the unit is in the standby mode, press the STANDBY button on the front panel or remote control to turn on this unit.

Press the STANDBY button on the front panel or remote control.

After turning on this unit, it detects the input signal automatically. When there is signal input, it receives the input signal automatically. Otherwise, the unit will automatically search signals all the time.

When there is signal input but it cannot receive

The signal automatically, press the INPUT button on the remote control to select the input signal.

When the unit is in normal working mode, press the STANDBY button on the front panel or remote control if you want to enter standby mode.

Please turn off the power when you are not going to use the unit for a long time.

Please turn off the power every time after you

use the unit.

Press the " POWER" button on the front

panel to power off this unit.

POWER

2.2.2 OTP function

We have set the OTP function to simplify the

operation of testing sound effects.If the played

disc is movie or story, you just press the MOVIE

button and the system will automatically set

standard movie mode.If the played disc is music,

you just press the MUSIC button and the system

will automatically set standard music mode.If

you want to sing Karaoke, you just press the

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K.R.OK button after inserting microphone and The system will automatically set standard

Karaoke mode.

Press the MOVIE button to set standard

theater surround mode.

Automatically detect the input signal source. If many signal sources input, it will select the current signal input preferentially.

Automatically set the parameters of surround. If 5.1CH input signal is detected, it will automatically adopt standard mode; if 2CH signal source is detected, it will automatically adopt Cyber Logic.

Press the MUSIC button to set standard music modeAutomatically detect the input signalsource. If many signal sources input, it will select the current signal preferentially.

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.

2.2.3 Select Input Sound Source

This unit utilizes two input lines of stereo audio sources: VCD, DVD; one line 5.1 channel signal input. Select the input signal source manually through the remote control.

Press the INPUT button on the remote control, and "INPUT TUNER" splays, which means TUNER has been selected.

Press the INPUT button on the remote control, and "INPUT VCD" displays, which means VCD 2CH input jack has been selected.

Press the INPUT button on the remote control, and "INPUT DVD" displays, which means DVD 2CH input jack has been selected.

Press the INPUT button on the remote control, and "INPUT 5.1CH" displays, which means

5.1CH input jack has been selected.

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, second and third Bass Enhancer; the subwoofer signal adds into the master channelsignal; turn 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.

2.2.5 Select Sound Field

1 HI-FI In 2CH signal input, you may select the Hi-Fi mode to keep the originally musical features.

Press the HI-FI button on the remote control and "HI-FI" will displays, which means the system enters the Hi-Fi mode; if "NVALID" 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.

Press the STANDARD button on the remote control and "STANDARD" will display, which means the system enters standard sound field.

3 Cyber Logic

In order to make 2 channel input signals have multi-channel sound field effect, you may select Cyber Logic sound field.

Press the CYBER LOGIC button on the remote control and "CYBER LOGIC" will display, which means the system enters Cyber Logic sound field: if "INVALID" displays, it means the system cannot enter Cyber Logic

Cyber Logic mode is invalid in 5.1 channel signal input.

2 Standard

In order to keep the correspondence with input signals and adjust output timbre according to personal habit, you may select the standard sound field.

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.

Press the SURR button on the remote control in 5.1 channel signal source input, the surround will display.

Press the SURR button on the remote control Repeatedly; you may select the environment

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Modes between Affectional movie, Sowordsmen movie, Gunfignt movie, Sci-fi movie and music.

The environment surround is invalid in 2-

channel signal input status.

The environment surround is invalid if

microphone is inserted.

2.2.6 Adjust Volume

1 Master Volume When the current sound is too high, too low or unsuitable, you may press the MASTER VOL on the front panel or remote control to adjust the volume of all channels.

Press the "+" button of master volume on the front panel or remote control to increase all channels' volume simultaneously; the max volume is 60.

Press the "-" button of master volume on the front panel or remote control to decrease all channels' volume simultaneously; the min volume is 0.

The master volume displays as the example: "VOL: 20”

2.2.7 Adjust Level

1 Left channel level

When sound of left and right channels is imbalance, you may adjust R channel level to make it in balance with L channel.

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 follows:

3 Center level

When sound of left and right channels is imbalance, you may adjust R channel level to make it in balance with L channel.

Press the SPEAKERS button on the remote control and "R: 00" will display. Operate as follows:

Press the “ " button on the remote control to increase the volume of R channel. The max level is +60.Press the “ " button on the remote 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 to the sound field.

Press the SPEAKERS button on the remote control and "SL: 00" will display. Operate as follows:

Press the " " button on the remote control to increase the volume of surround left. The max level is +60.Press the " " button on the remote control to decrease the volume of surround left. The min level is -60. NOTE: The surround left level cannot beadjusted only when left and right channels have output.

When sound of surround right is unsuitable, you may adjust surround right level to make it suitable to the sound field.

Press the SPEAKERS button on the remote control and "SR: 00" will display. Operate as follows:

Press the " " button on the remote control to increase the volume of surround right. The max level is +60.Press the " " button on the remote control to decrease the volume of surround right. The min level is -60. NOTE: The surround right level cannot be adjusted only when left and right channels have output.

6 Subwoofer level

When sound of subwoofer is unsuitable, you may adjust the volume of subwoofer speaker and the level of subwoofer channel to make it balanced to the sound field.

Press the SPEAKERS button on the remote control and "SW: 00" will display. Operate as follows:

Press the " " button on the remote control to increase the volume of subwoofer. The max level is +60.

Press the " " button on the remote control to decrease the volume of subwoofer. The min level is -60.

NOTE: The subwoofer level cannot be adjusted only in Hi-Fi and Bass Enhancer conditions.

2.2.8 EQ function

Due to the personal like to music, you may adjust EQ to meet your own needs. If the music tempo is not enough or full, adjust bass; if the voice is unclear, adjust middle frequency; if the musical details are not rich, adjust treble.

1 Pre-set EQ

When the sound of master volume is too weak or unclear, you may directly use pre-set EQ mode to make it accordant with the current music. This unit utilizes 8 EQ modes: Rock, Jazz, Classical, Pop, Disco, Rap and Blues.

Press the EQ button on the remote control to display the EQ curve.

Press the EQ button repeatedly to select the EQ mode accordant with the current music.

EQ mode cannot be adjusted in Hi-Fi mode. 2 Multi-band EQ

When the sound of master volume is too weak or unclear, you may set EQ mode yourself to meet you own taste.

Press the "AUTO EQ" button on the remote control to display the current EQ curve. There is a cursor flashing in the current frequency.

Press the " " button on the remote control to select the high 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.

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Press the AUTO EQ button on the remote

control to display the analyzing curve.

EQ function

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

control and "CALL 1-8" displays.

according to the default parameters. 2 Memory Parameters

first to display "SAVE "

control again under the display "SAVE "

corresponding number buttons and "SAVE 1-8" displays.

3 Call parameters

first to display "CALL "

control again under the display "CALL "

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

Press the number buttons 1-8 on the remote

Setup will be processed automatically

Press the "SAVE" button on the remote control

Press the number buttons 1-8 on the remote

The current parameter is memorized into the

Press the "CALL" button on the remote control

Press the number buttons 1-8 on the remote

The parameters memorized in the number

channel level is too high or too low, the system will adjust automatically

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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.

3 Treble

When inserting microphone to sing Karaoke, you may adjust microphone treble when the sound is unclear.

Press the "TONE" button on the remote control twice, then press " " or " " to adjust the treble of microphone. The adjustable range is 6

The microphone treble displays as "MIC TREBL+2”

The microphone treble cannot be adjusted when not inserting microphone.

4 Echo When inserting microphone to sing Karaoke, you

may adjust microphone echo when the sound is weak or not full.

Press the "ECHO" button on the remote

control then press or to adjust the echo of

" "

microphone. The adjustable range is 0~7.

The microphone echo displays as "MIC ECHO

2”

The microphone echo cannot be adjusted

when not inserting microphone.

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5 Delay When inserting microphone to sing Karaoke, you

may adjust microphone delay when the sound is not full.

Press the "DELAY" button on the remote

" "

control then press of to adjust the delay

" "

of microphone. The adjustable range is 0~7..

The microphone delay displays as "MIC DELAY 2”

The microphone delay cannot be adjusted when not inserting microphone.

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.

Press the "WF" button on the remote control to display "MIC WIDE ON", which means Karaoke Wide Sound Field is switched on.

Press the "WF" button on the remote control again to display "MIC WIDE OFF", which means Karaoke Wide Sound Field is switched off.

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 the sound is unsuitable.

Pressing the "MODIFY" button on the remote

control can circularly select the euphonized

¡ï

voice"NATURAL", "Full", "Fruity", "Bright" and "Ringing".

The MODIFY button cannot be selected when

not inserting microphone.

2.2.11 Tuning Function

Auto Tuning One:

1 Press INPUT button on the front panel or remote control to select TUNER as the input sound source.

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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3 Press TUNING / button on the front panel or remote control for above 5 seconds to automatically tune upwards/downwards until your needed radio station programs. When programs are searched, it will stop searching automatically.

3¡¢

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 manual tuning method.

Clear Radio Station

If you do not need the preset radio station, you may clear it by using CLEAR button on the remote control with the help of number buttons 0~9. 1 Press CLEAR button on the remote control. 2 Press the serial number of the radio station 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.

4 The following save and call operations are the same with manual tuning operations.

Auto Tuning Two:

1 Firstly select TUNER as the current input sound source according to the operations oF

"Manual Tuning", and then select the wave band to be received.

2 Press MEMORY button on the front panel or remote control, and then press TUNING / button for above 0.5 seconds during the course of displaying MEMORY to enter the radio station auto searching status.

NOTE: 1. This operation is beyond retrieve, so please take care to operate.

2. If you clear the radio station incautiously, you may save again according to the select operation.

The Explanation of MODE button

This unit has two working modes in the receiving status: AUTO/MANUAL

1 In AUTO working mode, if you select FM wave band, this unit will automatically recognize the radio station program is mono signal or stereo signal and keep the mono or stereo 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.

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Antenna Connection

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: 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

75 UNBAL.FM ANT terminal.

NOTE:Do not use the outdoor and indoor FM antennae at the same time.

How to Connect

Push the jack button to open it.

Insert the speaker cord.

Let go off the button to clamp thespeaker cord.

4 Connect the AM round antenna to the stand.

AM round antenna

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

GND (Grounding) terminal

In order to ensure the safety and decrease the interference, please well connect the GND terminal. The better grounding method is insert the metal pole into wet ground.

2.2.12 Other Operations

1 Mute 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.

Rotate

Mute

- 15 -

2 Child Lock To prevent the children wrongly pressing the 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.

The DISPLAY button cannot be selected when

no signals input.

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 spectrum display effects until auto switch.

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.

Default

- 16 -

ChapterThreePrincipleandServicing

SectionOnePrincipleofthePlayer

AV225T(RU)isanadvancedpoweramplifierwithcompletefunctions.Basedontheformerpower amplifiers,itadoptsLCDscreen,withskybluebackgroundmatchedwith16differentkindsofspectrum displaystyles,inaddition,thisplayeriswithtuningfunctionanditisanexcellentselectionforuserswho lovelisteningtoradio.

3.1.1Compositionoftheplayer

1.Volumeboard:selectinputsignalsource,CyberLogicandbassenhancercontrol.

2.Signalprocessingboard:Karaokesignalprocessingand5.1CHsignalamplifying.

3.MCUboard:playercontrol,frequencypointgating,andautosearchcircuit.

4.Controlpanel:LCDdisplay,remotekeyboardandbackgroundlightdisplay.

5.Powerboard:supplytheworkingvoltagerequiredbyeachunitcircuitandperformplayer

protectionfunction.

6.Poweramplifierboard:performpoweramplifyingto5.1CHanalogsignal.

7.Digitaltuner:receiveradiosignalandthensendtopoweramplifierforsignalprocessing.

8.MIC,headphoneboard:MICsignalinput,headphoneamplifyingoutputcircuit.

9.Videoinputandoutputboard:fulfiltheswitchofVCD,DVDchannel.

3.1.2Functionandfeatures

Built-in5CHpoweramplifying,applicabletoAC-3/DTSandstereomusicreplay.Mainchannel

◆

80W,central/surround15Wwithstrongpower.

◆

AC-3/DTS,VCD,DVDinputjackandsubwooferoutputjack.

◆

6CHvolumecontrolandseparatelevelcontrol,with7-bandelectronicequalization.

◆

Bassenhancersystem,CyberlogicfunctionandHi-Fiplaybackfunction.

◆

Q-playfunctionofmovie,musicandKaraoke.

◆

MultipleEQmodes,applicabletodifferentmusicstyles.

◆

Autospectrumanalysiscompensationfunctionperformscompensationtosignalsautomatically.

◆

CompleteKaraokefunction,includingseparateMICvolumecontrol,high/lowtoneadjustment,

voicecompensation,delayandechoadjustment,Karaokewidesoundfieldfunction.

-17-

XS1

Powerboard

XS2

220V

XS3

Signaloutput

XL100

XS4

XS7

XS8

SWM RLY0

P_RC

OVER

R2 C2 SL2

SR2

VC+

GND

VC-

XP7

XP8

XP13

XP9

RLY P_RC

P_LRM P_CSM

SWM

L1 R1 C1

SL1 SR1

XS13

XS9

Videoboard

Volumeboard

XS20

XP20

Xp101

XS101

XP101

Tunersocket

XS22

XP22

SWITCH

Transformer elementary

Transformer

Sublevelcoil

XP23

+12V

GND

-12V

Controlpanel

DGND

+12V

GND

-12V

XP25

MICholder board

D+5V

XS25

CPUboard

XP12

XP100

XS6XS23

XS102

XP102

XS103

XP103

XS12

TUNER(L/R)

VCD(L/R)

DVD(L/R)

5.1CH(L/R)

Volume board

5.1CH(C/SL/SR)

5.1CH(SW)

Input selection

DLSPLY

A B

L/R

Follow buffering

L/R

5.1CH(C/SL/SR)

5.1CH(SW)

S-C C/SL/SR/SW

MIC

Mix

Cyber logic

S-C/S-SL/S-SR

S-C

D-SW

A B

5.1CH LR_T

Channel selection

LR_T

5.1CH

C/SL/SR

Mix

Electronic volume

L/R

SL/SR

L/R/C

Headphone amplifier

MIC

MIC, headphone board

MIC input

Signal board

VCD

2 3

DVD

4 5

V-OUT

Video in/out board

C/SL/SR

Power amplifier board

CD4051

Mute

Power amplifying

Load

test

AGND

+12V

-12V

Preposition power

VS+ GND VS-

Power

SW-OUT

volume

tone

Amplifying

amplifying

Program

Amplifying

+6.8V

AGND

-6.8V

Switch in bass enhancer and line output

filtering

compare

Bandpass

Dual-limit

boost

Low frequency

Detect

switch

channel

Detect

EEPROM

24C02

echo

Electronic

Echo

adjustment

Delay

adjustment

Sampling

intermit

P_SELECT P_SEARCH

Reset

circuit

CPU board

Reverse

VSTNDANCK

P_CHARGE

CPU

DIST

MIC direct connection

P_DO-P_D7

RST/RS/RW/PE

P REM

PT2222 remote control buttons array

DVD all-in-one input

amplifying

Preposition

MIC

+12V

AGND

3.1.4 The player signal flow chart

The player signal flow chart is shown as the following figure 3.1.4.1:

-12V

Power

±6.8V

Mixed

L/R

Mixed

Clipping

OK-R

Mixed

Clipping

OK-L

LCD display

OKL/OKR

SR/SL

+12V

Power

AGND

±6.8V

-12V

-VS

Remote control receiving

Mixed Mixed Mixed

+6.8V

AGND

-6.8V

+5V

Control panel

Protection circuit

Relay

drive

Relay

SW mute and relay state detect

VC+

AGND

VC-

Main power amplifier power

Power board

R C SL

- 19 -

Figure 3.1.4.1 The player signal flow chart

Section Two Unit Circuit Principle

3.2.1 Volume board circuit

AV225T (RU) has 4 kinds of input means in all: tuning input, VCD, DVD stereo input and 5.1CH

input. The Cyber logic function of AV225T (RU) is to achieve C, SR, SL and SW signal through buffer and

processing of adder and subtracter after sampling from L, R channels. In this circuit, electronic

simulation switch is adopted to fulfil the switch in all kinds of state. Signal flow is shown as the following

figure 3.2.1.1:

Tuner

VCD

DVD

1CH

N101

CD4052

Electronic switch

N10

N105B

N10

S SR

S SL

S-C

N104A

4053

Electronic switch

N102

4053

Electronic switch

N103

N104B

N106

OUT

M62446

SWIN

N107A

N108B

DISPLY

Figure 3.2.1.1 Volume board signal flow chart

- 20 -

1. Input selection and sound field processing mode

A X B Y C Z

0 X0 0 Y0 0 20

1 X1 1 Y1 1 Z1

Mode Pin

Tuner VCD DVD 5.1

A 0 1 0 1

B 0 0 1 1

The input selection of AV225T (RU) is fulfilled through electronic switch CD4052 and CD4053, and

the truth value table is shown as follows:

CD4052 Truth value table

CD4053 truth value table

(1) 5.1CH input state: now A, B, 5.1CH of M62446 are in high level, L and R channel signals of

5.1CH input terminal are outputted from pin 3, 13 of N101 respectively and then sent to IC N106 for

volume and tone adjustment; meanwhile C, SR, SL signals of 5.1CH input terminal are outputted from

pin 14, 15, 4 of N102 and then sent to IC N106 for separate volume adjustment; in addition, SW signal of

5.1CH is outputted through pin 4 of N103, amplified by N107A and then sent to M62446.

(2) 3 kinds of analog input modes: AV225T (RU) has 3 kinds of analog input modes: tuning signal,

VCD and DVD are controlled through signals A, B separately. Please refer to CD53 truth value table for

reference.

(3) AV225T (RU) has 3 kinds of sound field modes in all: standard, Cyber logic and Hi-Fi.

A. Standard: under the control of the player MCU, when bass enhancer is off, left channel, right

channel and subwoofer have output; when bass enhancer is on, only left and right channels have output.

B. Hi-Fi: under the control of MCU, only left and right channels of M62446 have output; when bass

enhancer is off, volume adjustment is off.

C. Cyber logic: pin 9, 10 of electronic switch N101 (CD4052) select a group of analog left and right

channel input signals according to the truth value table, the left and right channel signals are outputted

from pin 3, 13 through the electronic switch inside N101 and divided into 2 ways: one way is sent to pin

13, 15 of M62446 for electronic volume and tone adjustment, and the other way gets SW, S-SR, S-SL

and S-C signals though buffer and adder and subtracter, in which S-C, S-SR and S-SL signals are sent

to pin 12, 2, 5 of N102, under the control of 5.1CH signal, N102 selects Cyber logic signal input (see

Cd4053 truth value table) from Cyber logic and 5.1CH signal, central, right surround and left surround

signals are outputted from pin 14, 15 and 4 respectively and then sent to pin 11, 8 and 9 of M62446 for

volume adjustment. Another SW signal is outputted from N107A and then sent to pin 6 of M62446.

5.1CH signal sen t to M62446 outputs from pin 31, 36 after volume adjustment, and then is outputted by

XS20 flat cable holder to signal board.

(4) The relationship between the switch in all kinds of sound sources and sound handling mode in

input circuit is show as the following figure 3.2.1.2:

- 21 -

Only L/R channel has output, sound field and EQ setup is invalid

Only L, R and SW channel has output, capable of performing sound field and EQ setup

6CH output, capable of performing cinema sound field and EQ setup

Press INPUT button to select circularly

Hi-Fi mode

2 kinds of analog input modes

5.1CH input mode

Figure 3.2.1.2 Illustration between input circuit

Standard mode

Cyber logic mode

6CH output, capable of performing cinema sound field and EQ setup

2. Control circuit

The latched, data and clock signals outputted by MCU (N100) pin are sent to pin 39, 40, 41 of

M62446, pin 1, 2, 3, 4 of M62446 output control level to select the input signal and spectrum sampling

signal. Other functions, such as volume and tone adjustment, are also controlled by the three control

signals. The display of display screen is controlled by CPU directly.

3. Spectrum sampling circuit

The spectrum sampling in AV225T (RU) is sent from pin 13 of N103 to N108B for amplification, and

then sent to spectrum gating circuit. 5.1CH of M62446 selects sampling signal. When selecting Cyber

Logic, 5.1CH control signal is low level, now pin 9, 11 of N103 is low level, and it is known from the truth

value table that the output is X0 and Z0 and this two sampling signals are grounded. It is known from

Cyber logic principle, centre, surround and subwoofer channels are all produced by left and right

channel signals, but in S-C signal, complete left and right channel signals are included, so it is ok to

sample from S-C only. Therefore, S-C signal is outputted through R195 (pin 13 of N103) to N108B and

added with OK-R signal for the amplification of spectrum sampling signal, and then sent through XS20

to frequency point gating and auto search circuit; the same, when selecting 5.1CH input, 5.1CH control

signal is high level, pin 14, 15, 4 of N102 select pin 14, 4 of X1, Y1, Z1 of N103 and connect to X1, Z1,

thus, the 6-channel signals are outputted through pin 13 of N103 to N108B and added with OK-R signal

for the amplification of spectrum sampling signal, and then sent to frequency point gating and auto

search circuit through XS20.

4. Tuning function

This player has tuning function, which provides a good selection for users. It directly controls digital

tuner through MCU to receive audio signal, and then output after amplification by power amplifier. The

clock and data line of digital tuner is commonly used together with M62446, the other two control lines

are directly connected to MCU, L, R signals after being handled by digital tuner are directly sent to pin 1

and 12 of N101 CD4052 for gating input.

- 22 -

3.2.2 Signal processing board circuit

IC SN IC name IC function IC SN IC name IC function

N201 4558

Operational amplifier performs preamplification to voice signals

N207 CD4051 Karaoke delay adjustment

N200 PT2315

Karaoke volume adjustment, including tone adjustment

N208 CD4051 Karaoke echo adjustment

N205 CD4053 Electric switch N204 4558 Inverter

N209 PT2399 Karaoke echo settlement

The signal board performs mixed amplification to 5.1CH signal sent from volume board, voice signal

sent from microphone, headphone board and Karaoke echo signal.

1. AV225T (RU) Karaoke circuit

(1) Function: this circuit is to reset by loudspeaker after handling voice and being amplified by

power amplifier. It includes voice beautification circuit, wide sound field processing circuit and Karaoke’s

echo and delay adjustment circuit.

(2) Function of IC of Karaoke circuit is shown as the following table:

(3) Karaoke signal flow chart

MIC

N20A1

N202A

V200

N200

P_OKT

N202B N203B

N100

Figure 3.2.2.1 Karaoke signal flow chart

N211 N100

N209

N207

N208

N204

Directly connected

N205

Mixed output

Shown as in the figure 3.2.2.1, when microphone is inserted, MIC signal is sent to N201A

operational amplifying circuit for amplification. One path of MIC signal after being amplified gives MCU a

microphone input identification signal P_OKT through VD201 rectification filtering control triode V200

after being amplified by N202A; when there is signal input, P_OKT is low level, MCU makes N210

CD4094 send out KM low level signal to make triode V103, V105, V104 ccutoff and then to make MIC

signal can output; the other path is coupled by C219 to pin 6 of PT2315, and then output from pin 16

after internal volume adjustment to N202B and N203B for amplification. The signal after being amplified

of N203B is divided into two paths, one path outputs directly, and the other path is coupled byR222,

C247 to PT2399 inside for delay and echo adjustment and then outputs from pin 14, and then mix output

- 23 -

Together with direct connection OK signal through N204B, while OK-R is outputted from pin 14 after

being gated by N205 and then overlapped to left and right channels.

In this circuit, the low frequency exalt network composed by triode V201 connected to the reverse

end of N202B is mainly to exalt 75HZ low frequency signal.

When performing delay adjustment to PT2399, firstly give control signal to MCU, and MCU controls

N207 after being extended by N211 IC CD4094, then selects different resistance value to connect into

pin 6 of PT2399 to reach the purpose of delay adjustment.

Similarly, through changing the resistance value in R229 to change the echo level overlapped to

direct connection signal, the echo adjustment is realized.

The wide sound field control signal of Karaoke is sent by N211 to pin 11 of N205, when it is high

level, pin 14 of N205 is connected to X1, now the phase of OK-R signal is reverse from that of OK-L,

sound field is widened and Karaoke is in wide sound filed state. On the contrary, the phase of OK-R

signal is the same with that of OK-L, Karaoke is in the narrow sound field state.

In addition, microphone plug has a detect signal P_MICDET, and it composes the detection to

microphone inserting together with the circuit composed of V202. When microphone is not inserted, it is

low level, V202 cutoff; when microphone is inserted, it is high level, V202 is on, now turn off scene

surround mode and forbid tuning.

Otherwise, there is OK auto mute function. When P-KT cannot detect any signal in a continuous

period, MCU will send out a control signal to make KM be high level, triode V103, V105, V104 is on to

mute OK signal to advance SNR of the player and better listening effect.

(4) Scene mode signal flow

AV225T (RU) has a special function, that is, it may realize switch in 5 kinds of scene mode when there

is no Karaoke, which is fulfilled by Karaoke part. Signal flow chart is shown as in the figure 3.2.2.2:

R- 1

L -1 C- 1

N205

Mixed output

N203B

N209

N207

N208

N204B

Figure 3.2.2.2 Scene mode signal flow chart

When pin 9 and 10 of N205 is in high level, the sampled L, R, C signals are outputted by pin 3

through N205 gating, after being amplified by N203B, one path is sent to PT2399 inside for echo and

delay adjustment (controlled by IC CD4094), the effect after adjustment is overlapped to L, R, C channel

- 24 -

To form various scene modes. Seen from this, its principle is the same with that of Karaoke. In scene

mode, it functions only when microphone is not inserted and in 5.1CH mode at the same time.

2. Bass enhancer circuit

BURST sent out by N210 is bass enhancer on/off signal. When it is high level, it is added to base

electrode of V102, V102 is on, base electrode outputs low level, V107, V100 are cutoff, SW signal

outputs to external terminal normally, at the same time, BURST high level signal is added to emitting

electrode of V108, V108 is on, collector electrode output high level is added to the base electrode of

V101, V101 is on to make SW signal grounding and it will not be overlapped to left and right channel

signals.

Reversely, when BURST is low level, V100 is on, SWM signal cannot output from external terminal,

at the same time V101 is cutoff, SW signal is overlapped to left and right channel signal.

Bass enhancer of AV225T (RU) is divided into 3 levels, the principle is to change the high/low of

bass enhancer level through changing SW output volume of M62446.

Meanwhile, SWM signal is added to relay through XS9, when relay is disconnected, SWM signal is

grounded to make subwoofer terminal have no output to avoid the concussion to speakers at the

moment of power-on.

3. 5.1 signal and Karaoke signal mixed amplification circuit

Left and right channel signals of 5.1 signal, after being mixed with SW signal and being amplified by

N101B, N100B, are sent to the reverse end of N101A, N100A, at the same time, OK-R, OK-L signals are

respectively added to the reverse end of N101A, N100A and then output from pin 1 of N100A, N101A to

power amplifying circuit for amplification after the mixed amplification of N100A, N101A.

Meanwhile, the centre C-1 signal sent from volume board is added to the pin 6 reverse end of

N102B, and then added to the reverse end of N102A after amplification. Now the C1-1 signal after

processed by echo (scene surround mode) is also required to add to the reverse end of N102A and

mixed amplifying with it, then sent to centre channel power amplification circuit.

Surround SR-1, SL-1 signal of the other path volume board is directly sent to surround channel

power amplification circuit.

One path of 5.1 signal after mixed amplification is sent to power amplification circuit through XS9,

the other path forms DIST signal (distortion detect signal) to MCU board through R111, R112, R142,

R145, VD100-VD104 to perform auto gain adjustment to control the volume output.

3.2.3 MCU board circuit

MCU board is composed of player control circuit, auto search input signal and spectrum analysis

circuit.

- 25 -

1. The player MCU control

N100 is the control centre of the player, various control instruction are outputted by it to each

controlled circuit to fulfil each control function. +5V power supply is adopted, and pin 40 is its power

supply pin. Pin 18, 19 externally connects with 12M crystal oscillator to provide itself with working clock

frequency. Pin 9 is its reset pin, when power on, +5V charges C106 through R100. The voltage on the

two ends of capacitor cannot change suddenly, so B-pole of triode V100 is low level, that is, V100 is not

on, a high level reset signal is given to MCU. When capacitor C106 charging finishes, V100 is on, now

reset finishes. Form of this kind of reset circuit is high level reset, and low level is kept.

When the player is working, information of power-on picture and Chinese characters when

operating displayed on display screen are all saved in the static memorizer inside MCU. N101 is a state

memorizer and it can save the working state of the player at the time of power-off and then call these

states until power-on next time to avoid the adjustment of users again. All kinds of user-set sound field

modes are also saved in it and can be called when necessary.

2. Input signal detecting, search circuit automatically

DISPLAY signal from volume board is sent to N103A for amplification, after being coupled by

capacitor C110, sent to the reverse end of voltage comparator N103B, outputted from pin 7 of N103B,

then sent to pin 16 of the player MCU through VD103, V101, R109, R107. When N103B outputs a high

level, Vd103 is in reverse cutoff state, B-electrode of switch pipe V101 is high level, now switch pipe

V101 is in on state, and then a +5V P_SEARCH high level is achieved through VD101 voltage regulating

to MCU, which means there is no signal input, and the search continues. When output terminal of N103B

outputs a low level, VD103 is in positive direction on state, B-electrode of switch pipe V101 is low level,

now switch pipe is in curoff state, MCU detects that P_SEARCH is low level, which means there is signal

input, at the same time, the search stops. The working principle is as follows:

(1) After power-on, under the control of MCU internal program, data signal is outputted to M62446,

then M62446 sends out high/low level to perform scanning to N101, N102, N103 each input port of

volume board, at the same time, P_SELECT is high level, V102 is on, now the in-phase end voltage of

comparator N103B is about 0.1V. When these input ports have no signal output, voltage of pin 6 of

N103B is less than 0.1V, pin 7 outputs 12V, Vd103 is in reverse cutoff state. It is known from the above

analysis, P_SEARCH is high level, which means there is no signal input. After all ports being searched

once, it enters standby state automatically; when a certain port has signal input, this signal is compared

with pin 5 of N103B through N108B of volume board and MCU board N103A amplification, if voltage of

pin 6 of N103B is more than 0.1V, pin 7 outputs -12V, Vd103 is in positive direction on state, now,

P_SEARCH is low level, which means there is signal input, through controlling IC M62446, MCU locks

this port that has signal input to enter normal playback.

(2) When pressing “GOTO” button on remote controller, through remote control receiver on the

panel, the switch from light signal to electric signal is performed, thus, pin 11 of MCU sends out a high

- 26 -

Level to make V102 in on state, and search also according to the above program.

3. Spectrum analysis circuit

(1) Spectrum analysis circuit is composed of auto spectrum gain adjustment circuit, frequency point

gating circuit, A/D conversion circuit and display output circuit, shown as in the following figure 3.2.3.1:

DISPLAY

N104

CD4051

Auto spectrum

Gain adjustment

+5V

N105C

}

A/D conversion

CPU

V105

V104V103

Figure 3.2.3.1 Spectrum analysis circuit

35HZ

134HZ

300HZ

N102A

1KHZ

2.2KHZ

6.3KHZ

16KHZ

CD4051

Frequency point gating

Pin 12 of MCU

Pin 14 of MCU

N108

}

MCU

(2) Auto spectrum gain adjustment circuit: in order to avoid the two conditions that when input signal

is too weak, screen display range is too low, or when input signal is too strong, full screen will appear,

AV225T (RU) has set auto spectrum gain adjustment circuit and adopted a single-channel 1-selected-

from-8 electronic analog switch N104 CD4051, with its truth value table shown as follows:

X0 X1 X2 X3

0 0

0 0 0 0

X4 X5 X6 X7

1 1 1 1

Through changing the resistance value of the reverse end grounding resistor of operation amplifier

N104, gain of the operation amplifier is changed. See the details of the working of the entire circuit. The

spectrum analysis signal source (DISPLAY), mentioned above, is sent to the in-phase input terminal of

operational amplifier N105C for amplification, and its amplified multiple depends on the ratio of the

resistor connected by feedback resistor R130 and N104 electronic switch. When main volume is too high,

through the control of MCU, N104 increases the resistance value of grounding resistor automatically and

- 27 -

Decreases the amplified multiple; when main volume is too small, N104 decreases the resistance value

of grounding resistor automatically and increases the amplifies multiple.

(3) Frequency point gating circuit: the signals after being amplified by N105C, through C115

coupling, are sent to the 7 bandpass filters composed by operational amplifier, the corresponding

frequency range can be confirmed through setting the capacity of its feedback capacitor. On the output

end of each filter, a half-wave rectification circuit is connected, through rectification filtering to the AC

signal after being amplified DC voltage is achieved. This circuit is mainly to realize frequency point

sampling function, which can represent the range of each frequency point in a complete sound signal.

If the low frequency part in sound signal is strong, the DC voltage on the output terminal of 35HZ,

100HZ filter will be higher, similarly, when high frequency part is strong, the DC voltage on10K, 16K filter

will be higher. The output terminal of this 7 filters is connected to 7 input terminals of electronic switch

N108 (Cd4051) to make this electrtonic switch quickly and circularly gating in each frequency point. On

the output terminal of pin 3 of N108 will output a series voltage values that stand for each frequency

point signal range, shown as in the following figure 3.2.3.2:

35HZ

100HZ

300HZ

1KHZ

3KHZ

10KHZ

16KHZ

Note: the voltage range in the figure is uncertain.

35HZ

Time interval of swich

Frequency point circular gating cycle

Figure 3.2.3.2 Frequency point signal range voltage value

(4) A/D conversion, display output circuit (two cases divided)

1) When there is no signal input, MCU sends a P_CHARGE high level signal to B-electrode of V104,

the positive direction end of comparator N102B is low voltage, for the reverse end of N102B gets the

partial pressure of R169, R172, thus it will make N102B output voltage with -12V about to make triode

V105 cutoff; C-electrode of V105 will give a high level P_ADINT0 to pin 12 of MCU to inform MCU of not

performing A/D conversion. (Pin 9, 10 of N108 has no action and keep in high level)

2) When machine detects signal, MCU sends a P_CHARGE low level signal to B-electrode of V104,

+5V voltage charges C137 through V103; when the voltage value of reverse end is reached, comparator

turns over, pin 7 of N102B outputs 12V voltage to make V105 on, C electrode is low level, after MCU

- 28 -

Receives low level signal, 35Hz level gating is immediately finished, and then switches to next

frequency Point 100Hz. During the course of conversion, P_CHARGE outputs an instant high level to

make V104 on, releases the voltage on C137, and makes the in-phase end of N102B begin the process

of 100Hz charging from 0 level. When 100Hz charging finishes, switch into the charge/discharge

process of the next frequency point, and this kind of process circles continuously under the control of

MCU. This period of charge, from 0 level to the point that turn over happens, stands for the signal range

of the current frequency point. The range is larger, time is longer and range displayed on screen is

higher; the range is smaller, time is shorter and range displayed on screen is lower. The digital pulse

outputted from the output terminal of N102B adds to pin 12 of MCU through V105 phase, MCU handles it

and outputs to panel and makes dynamic spectrum display on display screen. Originally speaking the

display of each frequency point performs one by one according to the sequency, for the above

circulation process is fast, on the screen we will see the process of a whole spectrum displays. Shown

as in the figure 3.2.3.3, the charge time parameter is frequency point signal range voltage value cyclic

parameter in the figure 3.2.3.2:

35HZ

100HZ

Frequency point signal range voltage

value switches into time interval

High level discharge

5HZ

100HZ

Switch time interval

Figure 3.2.3.3 Illustration of "Frequency point signal range

voltage value switches into time interval"

Charge time Charge time

3.2.4 Control panel circuit

Front panel control circuit is the window of man-machine conversation of the player, and it can

transmit various operation instructions to MCU to fulfil various operation. At the same time, it is also a

window of the player. Users control the working state of the player through it and it is also an important

composition of the appearance. Control panel circuit block diagram is shown as in the figure 3.2.4.1:

Drive circuit

MCU

Figure 3.2.4.1 Control panel circuit block diagram

LCD display

Power

Remote control receiving

- 29 -

Button

1. Power supply circuit

Control panel power supply of AV225T (RU) has two groups voltage of +3.3V and +5V. The +5V

voltage from signal board after voltage regulating supplies power for N102, N103 (74VHC245) and N101

PT2222 respectively through the voltage reduction of three diode VD105, VD106 and VD107.

2. LCD display drive and buttons circuit

This circuit is composed of N101, N102, N103 and LCD. The display is directly controlled by P0 port

of MCU, LCD is banded with IC inside. For working voltage of display screen is 3.3V, but the control

line level sent out by MCU is 5V, between MCU and LCD display screen, two IC 74VHC245 are used

to perform level conversion to change the +5V control level from MCU into +3.3V control level to control

the display of display screen.

Buttons circuit of this player is equal to a remote controller. Signal of buttons matrix is received by

PT 2222 and then makes infrared light emitting diode VD100 send out signal through the control of

triode gating by pin 7 , then send to MCU for processing after being received by remote control receiver.

3.2.5 Power board circuit

Power board provides each unit circuit of the player with required various working voltage. Shown

as in the figure 3.2.5.1, AV225T (RU) adopts a large power round transformer to supply power for main

channel, central and surround channel power amplifier.

9.8 V

220V 50HZ

Figure 3.2.5.1 Power board power supply block diagram

Panel display,

MCU power supply

Rectification

31V

filtering

Rectification

15V

filtering

Fan

Left/right channel power amplifying level

C , SL, SR channel power amplifying level

1. The two groups AC 31V outputted by the first time grade of transformer, through rectification

filtering of 8 In5404 and 2 large electrolytic capacitor (15000uF/68V), gets +/-43V voltage to supply

power for left and right channels.

2. The two groups AC 15V voltage outputted by the second time grade of transformer, through

rectification filtering of 4 In5404 and 2 electrolytic capacitor (4700uF/35V), gets +/- 21V voltage to

- 30 -

Supply power for SL/SR/C channels. In addition, for other IC and operational amplifiers, power is

achieved also through voltage regulation of 3-end voltage regulator L7812, L7912 by it to supply power

for other IC.

3.2.6 Power amplifier board and protection circuit

1. L/R channel power amplifying circuit

L, R channel power amplifying circuit of AV225T (RU) is composed of discrete components. The

composed block diagram is shown as in the figure 3.2.6.1: (take L channel as instance)

L IN

V101

V116 Mute

AC negative feedback

121,R109,C105

Difference amplification Stage

V102

Constant current source V104, V107,

Vd102, Vd103

,V103

Voltage amplification stage V105

Figure 3.2.6.1 L input block diagram

Composite power amplifying

V132 V112

Temperature compensation stage V106

Composite power amplifying V133, V113

Relay

Speaker

L channel signal, through R101, R103, C101 coupling, is sent to B electrode of V102; V102 and

V103 are composed difference amplifying circuit of single ended input and single ended output. Sound

signal outputs from C electrode of V102 to B electrode of voltage amplifying stage, and then outputs to

composite power amplifying stage after voltage amplification. V104, V107, VD102 and VD103 compose

constant current source circuit. VD102 and VD103 provide constant base electrode current for V104 and

V107. The emitter electrode resistor of V104 decodes working current of difference amplifying stage, the

emitter electrode resistor of V107 decides working current of voltage amplifying stage. V132 and V112

compose multiple unit tube amplifying to make the final stage of power amplifier have strong current

amplification capacity and they compose waveform positive half cycle amplification. V133 and V113

compose the negative half cycle amplifying of waveform and its circuit structure is the same with that of

upper tube. The function of temperature compensation tube V106 in the circuit has two: firstly, it is the

base electrode bias of upper/lower multiple unit tube and its working state decides the static working

current of composite power amplifying stage, that is, we can set the static working point through

adjusting the on degree of V106, and the usual method is to change the base electrode resistor of V106;

secondly, it can automatically adjust the working state of composite power amplifying stage when

temperature increases, and the adjustment process is as follows:

- 31 -

Total current of output stage = working current + leakage current

When temperature increases, the increase of leakage current leads to the drift of static working

point (unfavourable), at the same time, the leakage current of V106 increases, Uce decreases to make

the bias current of output stage decrease to make working state change and working current of back

stage decrease to reach the purpose of temperature compensation.

Introduce voltage negative feedback to power amplifying circuit of AV225T (RU) and it is composed

of R121, R109 and C105, which can stabilize static working point of difference stage. AV225T (RU)

adopts direct output means, R111, C116 (on power board) connected with output end compose Zobel

Network to prevent the high frequency self-exitation caused by the AC inductive reactance of speaker

voice coil.

2. Mute circuit

When pressing MUTE button on remote controller, after the photoelectric conversion performed by

infrared receiver, a mute signal is achieved to send to MCU, which sends out P_LR high level and

P_CSM high level mute instruction at the same time. P_LRM high level make 2N5401 (V115), S8050

(V101), S8050 (V116) on, left/right channel signal is short circuited to ground to fulfil the mute control

function of left/right channel; P_CSM high level makes 9014 (V150)on, 2N5401 (V130) and S8050 (V131)

on, centre channel signal is short circuited to ground and centre channel mute control function is fulfilled;

at the same time, the on of 9014 (V150) makes 9014 (V151) cutoff, voltage of pin 5 of TDA7265 is

positive power voltage, TDA7265 internal mute circuit works to reach surround mute function. When

headphone is inserted, HEADPHONE controls LRM and SCM through VD203 and VD204 to make

main channel, centre and surround channel mute.

3. C, SR, SL power amplifying circuit

Compared with the former models, the three channels of AV225T (RU) adopt power amplifying IC

CD1875CZ (N104) and TDA7265 (N106) special for audio. As for TDA7265 (N106), it has 11 pins in all,

pin 3, 1 and 6 are its positive and negative power pins respectively; pin 10, 8 are its reverse input end,

the rated output power of each channel of this power IC may be up to 15W and it is with function of auto

mute when power on; it has 5 pins in all, and it is a good-performance power amplifying IC, the

application circuit is simple and has 15W power output in rated state. Pin 5 and 3 are positive/negative

power pins.

4 Protection circuit

Protection circuit of AV225T (RU) power amplifier is on power board. Protection means of L, R, C

channel is through disconnecting relay Y100 when protection starts up to disconnect its output. SR, SL

channel fulfils the protection function through mute. AV225T (RU) is with power-on delay protection,

central point over-voltage and over-current protection, standby protection.

- 32 -

(1) Power-on delay attracting protection circuit: when power on, working of circuit is stable, and the

produced current has great damage to speaker and power amplifier, so delay attracting protection circuit

is set. Power-on delay attracting protection circuit is divided into 2 steps: 1. C, L, R channel working

process: the AC outputted from transformer, through rectification filtering of Vd113, C110, gets +22V

voltage to make VD111 reverse broken-down through charge to C115 by R108 to make Vd111 reverse

broken down to make V105, V104 positive direction on to make relay Y100 attracting to realize delay

attracting effect. SR, SL channels performs concussion protection when power-on/off through the

following means: after machine system resets, MCU outputs a P_CMS high level signal to make V150

on and make V151 cutoff; pin 5 of TDA7265 is power voltage, TDA7265 outputs mute. After delay start-

up of machine succeeds, the output signal P_CMS of MCU switches into low level immediately, V150 is

cutoff to make V151 on, voltage of pin 5 of TDA7265 is about 5V lower than power voltage, SL/SR

channel resumes normal output.

(2) Over-voltage protection: on each channel’s output end, a over-voltage sampling resistor is

connected, L channel is R116, R channel is R117, C is R118, SR and SL are R120 and R119 respectively.

When just one channel’s central point voltage is more than +3.5V or less than -3.5V, V101 or V102 is on

to make their C electrode voltage decrease, B electrode of V103 is pulled down to make V103 on, relay

is disconnected finally and over-voltage protection is fulfilled. Working process is shown as the following

figure 3.2.6.2:

Over-voltage sampling resistor is connected to each channel

L channel is R116

When more than +3.5V

When less than -3.5V

Figure 3.2.6.2 Over-voltage protection flow chart

V101 is on

V102 is on

Voltage of C electrode decreases

V103 is on

Relay disconnects and protection starts up

(3) Over-current and short-circuit protection: on the output load resistor of L, R channel, a over-

current sampling triode is connected. Sampling triode of L channel is V114 (on power amplifier board),

load resistor is R126, R127 (on power amplifier board). C, SR, SL channel power amplifying IC is with

over-curent protection function inside. Only over-current appears in L channel, the voltage decrease

that produces on R126, R127 will increase. Once the voltage decrease of R129 (on power amplifier

board) is more than 0.7V, V114 will be on, V103 is also on, and relay is disconnected finally and short-

circuit protection is finished. Working process is shown as the following figure 3.2.6.3:

Over-current sampling triode is connected to each channel

L channel is V114

Figure 3.2.6.3 Over-current and short-circuit protection flow chart

Voltage decrease on R126, R127 increases when over-current

- 33 -

V114 is on

C electrode voltage decreases

V103 is on

Relay disconnects and protection starts up

Similarly, when over-current appears in R channel, (on power amplifier board) voltage on R159 will

be more than 0.7V to make (on power amplifier board) V129 on, and also make V103 on, relay is

disconnected finally to reach the purpose of protecting speaker.

3.2.7 MIC, headphone board

MIC signal is directly sent to signal processing board through flat cable XP12, the principle has

been specified in section 3, so it is omitted here. The main element of headphone part is headphone

amplifier N100 PT2308. It is a dual-channel operational amplifier, has 8 pins in all and adopts signal

power (+5V) to supply power. Pin 1 and 7 are two channels’ signal output ends; pin 2 and 6 are two

channels’ reverse input ends; pin 3 and 5 are two channels’ in-phase input ends; pin 8 and 4 are positive

and negative power pins.

When no headphone is inserted, headphone detect signal PH_SW is low level, now the mute

control signals P_LRM and P_CSM of main channel, centre and surround channels are low level, these

5 channels all have normal output; when headphone is inserted, PH_SW is high level, now diode VD203

and VD204 on signal board make the mute control signals P_LRM and P_CSM of main channel, centre

and surround channels be high level, and make main channel, centre and surround channels have no

output on account of mute. Please refer to mute circuit part for the principle. At the same time, triode

V111 is made on through the resistor R166 on signal board, so V110 and V109 are cutoff to cut the

power supply loop of fan; when volume is more than 45dB, fan tunning is forbidden to facilitate to listen

with headphone.

Please be noted here that headphone detect signal PH_SW is not connected with MCU, but is set

by machinery structure of headphone jack.

3.2.8 Video in/out board circuit

AV225T (RU) is with two-channel composite video input (VCD, DVD or 5.1CH) and one-channel

composite video output (VCD, DVD or 5.1CH).

Input/video switch of video signal is realized through a electronic switch CD4051 (N101), the truth

value table is shown as follows:

X0 X1 X2 X3

C 0

0 0 0

X4 X5 X6 X7

- 34 -

0 1

When select VCD channel, pin 1 and 2 of N106 (M62446) of volume board sends out two control

signals of A and B, and one INH control signal. A=1, B=0, INH=0, known from Cd4051 truth value table

that output pin of CD4051 (pin 3) selects X1, ie, VCD channel, now, in terms of volume board working

principle in section 2, A and B also control gating of audio part CD4052, that is, audio channel also

selects VCD channel, thus, the synchronous switch of audio and video of VCD channel is realized.

Similarly, for the synchronous switch of audio and video of DVD channel, pin 1 and 2 of N106

(M62446) of volume board send out 0, 1 and INH=0 control signal of A and B to fulfil the corresponding

switch. When 5.1CH is selected, A=1, B=1, INH=0, the audio/video switch in 5.1CH is fulfilled.

At last, composite video signal outputs through triode V101 (1015) .

When INH=1, CD4051 gas no output.

- 35 -

Section Three Servicing Cases

3.3.1 Servicing instances

Instance 1 Trouble symptom: power-on protection

Description: relay not attracting and display “System abnormal, auto protection”.

Analysis and troubleshooting: system protection after power-on, relay not attracting; shown as in

the figure 3.3.1.1, test whether L, R, C, SL, SR of power board flat cable holder XP8 has DC output, pin 1

of power board flat cable holder XS7 is tested high level, pin 2 is low level, C electrode of triode V101 is

high level, known from the above test that protection is not caused by over-current and over-voltage

(you may also unplug XP7 and XP8 flat cable holder and check whether it also has protection). The

anode voltage of diode VD112 is tested 0, so relay is judged abnormal. It is normal after changing relay

and trouble is removed.

OVER P_RC RLY0 SWM

L2 R2 C2 SL2 SR2 VC+ GND GND VC-

XP8

CON9

XP7

CON4

1 2 3 4 5 6 7 8 9

R105 10K

V101 C9014

C110

220u/35V

V102 C9014

R116

51K

R117

51K

R118

47K

R119

47K

R120

47K

C122

104

C113

220u/16V

C114

220u/16V

XL101A

R106

WP6

4.7K

R109

VD110

IN4148

R108

100K

R107

100K

V103

C9015 C121 103

10k

XL101A

WP6

C115 47U/25V

13 14

VD111

5.1V R110

RELAY-4

Y100

VD112

1N4148

56K

5 2

6 3

7 4

SWM

RLY0

XL101A

WP6

V104 C8050

XL100A

WP4

XL100A

WP4

V105

C9014

VD113

R100

47/3W

1N4004

R102

RLY0

SWM

VD108

IN4148

R101

R111

4.7/1W

R112

4.7/1W

R113

4.7/1W

R114

4.7/1W

R115

4.71W

R103 47K

4 3 2 1

VC+

VC-

C1160.1u

C1170.1u

C1180.1u

C1190.1u

C1200.1u

C126

R104

10K

V100 C9014

103

L100

0.7UH

L101

0.7UH

Figure 3.3.1.1 Protection circuit diagram

Note: 1. After relay being used for a period, working state may be unstable and some abnormalities

will appear. For instance, relay not attracting after power-on sometimes; each contact point not fully

contacted after relay attracting; CPU not detect RLY0 signal (this signal is low level after relay attracting);

auto protection.

- 36 -

2. Power-on protection causes: over-current protection, over-current protection and CPU not detect

RLY0 signal: test whether each output channel has DC output; when power-on protection trouble

appears, make clear which kind of reason caused this. The common protection is that abnormal centre

or surround power IC causes that output signal has DC.

Instance 2 Symptom: no sound output

Description: system not detect signal after power on, no output when switching various sound

sources

Analysis and troubleshooting: select VCD channel after power on, input sine wave signal, shown as

in the figure 3.3.1.2; test volume board capacitor C133, C134, no signal; test volume board capacitor

C122, C121, also no signal; pin 5 and 14 of N101 have signal; test power voltage of pin 7 and 8 of N101,

normal; it is known primarily that N101 has input but no output, change N101 and N101 still has no

output after changing, so it is judged that N101has no problem, it is that A, B signal of N106 have trouble

when this channel has not been selected; change N106, output is normal after changing and trouble is

removed.

N101 CD4052

5.1CH

INH

N102

CD4053

INH

B C9VEE

VDD

Vss

VDD

VSS

VEE

A+6.8V

A-6.8V

A+6.8V

A-6.8V

R134

R135

R136

150K

R133 150K

C115

47u/16V

A+6.8V

C116

47n

INH

5.1CH

R157

100K

R160

100K

R161

100K

R162

100K

R158

100K

R159

100K

R153

22K

INH

5.1CH

R154

22K

C124

15n

C125

0.33u

R155 22K

C123 822

C117

4.7u/16V

C118

4.7u/16V C119

4.7u/16V

C120

4.7u/16V

C121

4.7u/16V

C122

4.7u/16V

18 19

R156

22K

OUT4

OUT3

OUT2

OUT1

AVDD

SWIN

N106

GNDS

M62446

SRIN

SLIN

GNDC

CIN

GNDR

RIN

GNDL

LIN

BYPASR

BYPASL

LTRE LBASS3

LBASS2

LBASS121RBASS1

DVDD

CLK

DATA

LATCH

DGND

AGND

SWOUT

SROUT

SLOUT

COUT

ROUT

LOUT AVSS

CL1

CL2 CR1

CR2

RTRE

RBASS3

RBASS2

C143

47n

31 30 29

C130

4.7u/16V

28 27

C129

4.7u/16V

26 25 24

C142

47u/16V

C138 4.7u/16V

C137 4.7u/16V

C136 4.7u/16V

C135 4.7u/16V

C134 4.7u/16V

C133 4.7u/16V

C13147n

C128

822

C127

15n

C126

0.33u

L101100uH

C141

101

SR1

SL1

C-1

R-1

L-1

A-6.8V

C132

47u/16V

C140

101

C139

101

5.1CH

VCD-R DVD-R

5.1CH-R

VCD-L DVD-L

5.1CH-L

S-C

5.1CH-C

S-SR

5.1CH-SR

S-SL

5.1CH-SL

Figure 3.3.1.2 Volume circuit diagram

Note: when there is no output, firstly make sure whether signal input can be detected; if signal input

can be correctly detected, it means that signal source conversion circuit has no problem, then make

sure whether it is a certain channel has no output or all have no output; if all have no output, it is

probably that power supply of certain part is abnormal, also it is mute signal that abnormal, etc. For

Cd4052 and Cd4053 belong to the electronic switch with high conversion frequency, they are easy to be

damaged; after being damaged, +6.8V and -6.8V voltage may probably be pulled down, or gating signal

A, B of 62446 will be pulled down, and then troubles, such as signal not detected and no output, will

appear.

- 37 -

Instance 3 Symmtom: no output

Description: after power on, connect to 5.1CH, main channel has no output, central and surround

have output, power board FL101, FL102 fuse is burnt down.

Analysis and troubleshooting: change fuse of FL101, FL102 and power on again. Fuse is burnt

down, power off, test resistance to ground of power board Vc+, Vc- and find that resistance is 0 ohm;

unplug power board flat cable holder XS8, shown as in the figure 3.3.1.3; test resistance to ground of

power amplifier board Vc+, Vc-, it is also 0 ohm, the trouble lies in power amplifier board by primary

judgment, test resistance in each pin of power amplifier board power tube V112, they are all 0 ohm,

resistance in each pin of power tube is 0 ohm, V112 and V113 have been broken down, change V112,

V113, change fuse, output is normal after power on again, and trouble is removed.

C101

10u/16V

R104

47K

C103

47u/100V

R1052KR106

V102

2N5551

C104 220p

R107 47

V104

2N5551

C107

47u/100V

V103

2N5551

R108

R109 1K

C105

100u/16V

VD102

1N4148

R110

VD103

510

1N4148

C108

33p/500V

R111

R114 2.7K

33K/0.5W

V106

2N5551

R115

1.2K

R112

R117

220/0.5W

R113

150

V105

2N5401

V107

2N5551

R116

150

R125

220/0.5W

C109

47n

V132

2SC5248

R121

33K

V133

2SA1964

R120

100/0.25W

R122

100/0.25W

P+30V

V112

2SD1047C

R128

4.3K

R126

0.25/7W

R127

0.25/7W

R130

4.3K

V113 2SB817C

P-30V

R129

2.7K

P+30V

P-30V

C110

1u/16V

V114

2N5551

VD104

1N4148

Figure 3.3.1.3 Power amplifier output circuit diagram

Note: when a certain channel has no output, firstly confirm whether voltage of power amplifying

circuit of each channel is normal. We often test stage by stage from the final stage of signal output and

then analyse. Vibration exists in the course of moving machines, the line of PCB board of signal board

will probably be broken off, or copper surface of element pin will fall off, so you should consider when

analysing problems.

Instance 4 Symptom: microphone has no output

Description: insert microphone after power on, that MIC input has been detected displays, but

microphone has no output.

Analysis and troubleshooting: after power on, insert microphone, microphone inputs sine wave

signal, shown as in the figure 3.3.1.4; test base electrode of signal board triode V105, it is low level, MIC

mute signal is normal, test signal board capacitor C245, C246, they both have no signal, test pin 7 of

signal board N202, there is no signal, considering that MIC input can be detected, test signal board

- 38 -

Capacitor C219, there is signal, power supply voltage of N200 is normal, the trouble lies in N200

PT2315 by primary judgment; change PT2315 and trouble is removed.

+12V

MIC1 GND GND

MIC-DET

XS12

1 2 3 4

CON4

C217

10u/16V

R243

10K

R2075.1K

V202

9014

P_MICDET

C200151

R20039K

-12V

N201A

4558

8 4

+12V

R204

100/0.25W

C208

C211

47n

C23610P

R240220K

-12V

N202A

4558

VD200

9.1V

100u/16V

C21910u/16V

R2132K

C252

10u/16V

8 4

+12V

Figure 3.3.1.4 MIC circuit diagram

C20247u/16V

C225

5.6n

C226

5.6n

VD201

1N4148

N200PT2315

REF

VDD

AGND

TREBL

TREBR

RIN

BOUT_R

LOUD_R

BOUT_L

LOUD_L

R2091K

C205

47u/16V

CLK

DATA

DGND

LOUT

ROUT

BIN_R

BIN_L

LIN

C221

10u/16V

C227

C228

R241

47K

68n

V200

9014

P_SCL

P_DATA

R22010K

P_OKT

C237

R216

103

5.6K

Note: when changing PT2315, microphone still has no output sometimes. Considering that PT2315

and N101 24C02 of CPU board commonly use P_DATA and clock line P_SCL, when 24C02 is abnormal,

the communication between CPU and PT2315 may probably be affected to cause no output for

microphone, so 24C02 is required to change sometimes.

Instance 5 Symptom: no sound output

Description: signal input may be detected after power on, but no signal output, no output when

switching various sound sources.

Analysis and troubleshooting: after power on, VCD channel inputs sine wave signal, check power

amplifier board Vc+, Vc- , Vs+ and Vs-, power supply is normal, test volume board capacitor C133.C134,

there is signal, test pin 4 and 5 of volume board flat cable holder XS20, there is signal, so it is sure that

volume board working is normal; test pin2 and 3 of signal board socket XS9, there is no signal, trouble

lies in signal board by primary judgment; test power supply voltage +12V and -12V of pin 4 and 8 of

N100, normal, left channel output is normal after changing N100, right channel output is normal after

changing N101, centre has no output when adjusting to Cyber logic state, test pin 3 of volume board flat

cable holder XS20, there is signal, test pin 4 of signal board socket XS9, there is no signal, test N102,

power supply is normal, change N102 and output is normal, so trouble is removed.

Note: because of unstable voltage, 4558 of some part will be burnt down, +12V, -12V is pulled down,

then whole system working is abnormal, so several 4558 are required to change sometimes.

- 39 -

Instance 6 Symptom: no OSD (on screen display)

Description: after power on, relay attracting, output signal is normal, LCD has no display,

background light of display screen is lighted when pressing buttons.

Analysis and troubleshooting: because background light is bright, it is confirmed that +5V voltage of

control panel is normal. When using remote controller, remote control function is normal, which means

that control panel +3.3V is normal; change LCD screen, display is normal and trouble is removed.

Note: when no OSD appears, firstly make sure whether display screen voltage is normal, whether

data buffer output is normal; because display screen is easy to damage, in most conditions, it is display

screen that is damaged.

Instance 7 Symptom: power not on

Description: not any reaction after power on, relay not attracting, no OSD

Analysis and troubleshooting: power on and observe that each fuse is normal, secondary stage

voltage of transformer is tested 0, primary stage voltage of transformer is tested normal, primary stage

resistance is tested infinite, so it is judged that transformer has been burnt down; change transformer

and trouble is removed.

Note: when power not on, firstly confirm that whether it is power not on or no OSD, whether part of

voltage or all voltage is abnormal; if it is that power not on, test step by step from power socket until the

trouble is found.

Instance 8 Symptom: remote controller has no function

Description: after power on, panel buttons have no function, remote controller has no function.

Analysis and troubleshooting: after power on, remote controller has no function, change its battery

and it also has no function, test pin 3 P_REM signal of CPU board socket XP100, when remote

controlling, this signal has no pulse waveform, test voltage of control panel resistor R102, it is +5V, when

checking the welding point of N100 remote control receiver, we found that pin has rosin joint, after

adding tin, remote control is normal and trouble is removed.

Note: buttons function and remote control function are all fulfilled by infrared receiver, when buttons

and remote control have no function, trouble may lie in remote control receiver.

Instance 9 Symptom: Microphone has no delay and echo

Description: after power on, insert microphone, set echo and delay in maximum, beat microphone

and there is no echo and no delay.

Analysis and troubleshooting: test pin 7 of signal board N204, there is no signal, test power supply

of N209 PT2399, it is normal; change PT2399, trouble is not removed; test resistance of signal board

capacitor C242, C243, C238, we find that resistance of C243 only has 2.5K; change capacitor C243 and

trouble is removed.

Note: no echo and delay for microphone is caused by abnormal working of Pt2399; one case is that

PT2399 is abnormal itself; the other is that PT2399 peripheral circuit has trouble. Porcelain capacitor in

peripheral circuit is easy to damage.

- 40 -

3.3.2 Troubleshooting process

1. Symptom: Karaoke has no sound

Analysis: for this kind of trouble, you may usually adopt signal injection method to check stage by

stage. If a certain stage does not give out disturbance sound, this stage has problem; this method is

generally preformed from back stage to front stage. Another is signal control method. Check stage by

stage from front stage to back stage. If a certain stage has no sound, it means that this stage has trouble.

The troubleshooting process is shown as the following figure 3.3.2.1:

Karaoke has no sound

Check signal board

Check

whether there

is sound signal on

C252,C217

Check

whether there

is sound on R219,

R221

Check

whether there is sound

on R230

Check

whether there

is sound on C245,

C246

Check

whether base

electrode of V104,

V105 is

0.7AV

Check N210 and MIC hole circuit

Check PT2315 and CPU signal

P-SCCL, P-DATA

Check N202 and its power supply circuit

Check N203 and its power supply circuit

Check whether V104 or V105 is stricken through

Check

whether E-electrode

of V103 is high

level

Whether

MICDET is high

level; whether PKT is

low level

Change V103

CPU, MIC hole and V200 are damaged

Figure 3.3.2.1 Troubleshooting process for "Karaoke has no sound"

- 41 -

2. Troubleshooting process for “No spectrum display” is shown as the following figure 3.3.2.2;

No spectrum display

Whether

V105 collector

electrode has high and

low level variation

No spectrum display

Check

whether VD118 is

normal

Whether

positive direction

voltage of N102B has

sawtooth

waveform

Check CPU, I C bus

Check power supply, V105 and peripheral circuit

Change VD118

Check V103, V104, VD115, VD116, C137

Whether

negative direction

voltage of N102B has

sawtooth waveform

Check N102 and peripheral circuit

Whether

N108 and CPU

control pin working

is normal

Check control signal, N108 and peripheral circuit

Check 7-segment bandpass filter, C115 and the auto gain adjustment circuit composed by N105

Figure 3.3.2.2 Troubleshooting flow chart for "No spectrum display"

- 42 -

3. Troubleshooting process for “Power-on protection” is shown as the following figure 3.3.2.3:

Power-on protection

Check

whether there is

central point

voltage

Check

whether protection

is fulfilled when signal is

added or main volume

is increased

Check

whether power

amplifier board resistor

R111, R141 has

open-circuit

Check

whether resistor R108

has open

circuit

Check which channel outputs DC and check this channel

Check whether the current-

protection diode or triode is damaged, or capacitor C115 is not good

Change resistor

Check

whether RLY detect

signal is

abnormal

Whether it is machine

vibration protection

Check whether power board VD108 is low level, and change V100

Change relay

Figure 3.3.2.3 Troubleshooting flow chart for "Power-on protection"

- 43 -

4. Troubleshooting process for “Cannot search automatically” is shown as the following figure

3.3.2.4:

Cannot search automatically

Whether

DISPLAY signal is

sent to the negative direction

terminal of N103A of

CPU board

Check CPU board spectrum sampling

and amplifying circuit N103, N108B of volume board

Whether

the in-phase

terminal of N103B is

low level

Whether

the in-phase

terminal of N103B is

low level

Whether

VD103 is normal

Check VD101, CPU, V101 and peripheral circuit

Check N103A amplifying and power supply circuit

Check V102 and peripheral circuit

Change VD103

Figure 3.3.2.4 Troubleshooting flow chart for "Cannot search automatically"

- 44 -

5. Troubleshooting process for “No output (2-channel)” is shown as the following figure 3.3.2.5:

No output (2-channel)

Check

whether power

supply of each channel

is normal

Refer to troubleshooting of "Power not on"

Check

whether mute circuit

signal is normal

Check

whether power

amplifier board XS8

has output

Check whether voltage of power board R100

is normal

Change relay

Check whether MIC holder

is normal and then check mute circuit

Change VD113

whether signal of

whether 12V voltage

of signal board

Change signal board N100, N101, N102

Check

X20 is normal

Check

is normal

N N

Check power supply circuit

Check

power supply of signal

board N106

Change N106

Check power supply and change N106

Figure 3.3.2.5 Troubleshooting flow chart for "No output (2-channel)"

- 45 -

6. Troubleshooting process for “5.1CH has no output” is shown as the following figure 3.3.2.6:

5.1CH has no output

Change

into 2CH and check

whether it has

output

Check

power supply of

N102, N103

Change N102, N103

Refer to troubleshooting of "2CH has no output"

Check power supply circuit

Figure 3.3.2.6 Troubleshooting flow chart for "5.1CH has no output"

- 46 -

7. Troubleshooting process for “Left channel has no output” is shown as the following figure 3.3.2.7:

Left channel has no output

Check

whether power

amplifier board flat

cable XS8 has

output

Check

whether power

board R113 has

output

Change relay

whether power

amplifier board flat

cable XS9 has

whether C101 has

R125, R127 power

Check

waveform

Check

waveform

Check

supply

Check

whether signal board

X200 is

normal

Check

power supply of signal

board N100

Change N100

Check power supply circuit

waveform of volume

power supply of N106

Check power circuit

Check

board C122

Check

Change N106

Check power supply circuit

Check whether R121 has DC voltage; check triode of amplification part of this channel and then change it

Figure 3.3.2.7 Troubleshooting flow chart for "Left channel has no output"

- 47 -

8. Troubleshooting process for “Power not on” is shown as the following figure 3.3.2.8:

Power not on

Check

whether each

protector tube is

normal

Check

whether voltage

of power board XP8VC+

and VC- is normal ( 4.35V);

whether 20 of power amplifier

board is normal; whether

+5V of signal board

is normal

Check

whether AC

output of each sublevel

of transformer is

normal

Change transformer

Figure 3.3.2.8 Troubleshooting flow chart for :Power not on"

Check

N N

whether each channel power is short-circuited to

ground

Check

the voltage

regulation capacitor of

short-circuited

power

Check the load circuit of this channel power

Change the burnt-out protector tube

- 48 -

Section Four Servicing Parameters

3.4.1 Signal waveform diagram

This section collects signal waveform diagram of audio, video and each unit circuit with the purpose

of helping servicing personnel to judge where the trouble lies accurately and quickly to promote their

servicing skills. Because of the difference of oscillograph brand, model and tuning, the servicing

personnel should pay more attention to check in daily work for some difference may exist.

1. Input signal (2-channel input) waveform diagram:

2. Volume board capacitor C122 (L) waveform diagram:

- 49 -

3. Volume board capacitor C121 R waveform diagram:

4. Volume board capacitor C120 C waveform diagram:

5. Volume board capacitor C119 (SL) waveform diagram:

- 50 -

6. Volume board capacitor C118 (SR) waveform diagram:

7. Volume board capacitor C117 (SW) waveform diagram:

8. Waveform diagram of outputting C133 (L) after volume adjustment:

- 51 -

9. Waveform diagram of outputting C134 R after vvolume adjustment:

10.C135 C waveform diagram in Cyber Logic state:

11. C136 (SL) waveform diagram in Cyber Logic state:

- 52 -

12. C137 (SR) waveform diagram in Cyber Logic state:

13. Output to flat cable XS8 after power amplification, pin 1 (L) waveform diagram:

14. Output to flat cable holder Xs8 after power amplification, pin 2 R waveform diagram:

- 53 -

15. Output to flat cable holder XS8 after power amplification, pin 3 C waveform diagram:

16. Output to flat cable holder XS8 after power amplification, pin 4 (SL) waveform diagram:

17. Output to flat cable holder XS8 after power amplification, pin 5 (SR) waveform diagram:

- 54 -

18. P_CHARGE waveform diagram after signal being detected:

19. P_ADINTO waveform diagram after signal being detected:

Note: C138 (SW) has waveform only when bass enhancer is in off state.

- 55 -

3.4.2 Key point voltage

1. Power board:

VC+=43.5V

VC-=-43.5V

VD113 cathode terminal 12.8V (19.3V when in standby)

Vd111 cathode terminal 6.3V (DV when in standby)

P-RC=0V (4.8V when in standby)

2. Power amplifier board:

L7812 pin 3 +12V L7912 pin 2 12V

TDA7265 pin 3 +20V Pin 6 20V

over 5.3V (0V when in standby) S-MVTE 0V (19.5V when in mute)

3. CPU board:

When in standby: V103 pin 5 2.0V (0.1V after signal being detected)

VD101 cathode terminal 3.45V (0.6V after signal being detected)

R175 (P_CHARGE) 0.65V (waveform after signal being detected)

R179 (P_ADINTO) 5.0V (waveform after signal being detected)

- 56 -

Section Five Function Introduction to IC

3.5.1 function introduction to 4558

1. Description The RC4558 and RM4558 devices are dual general-purpose operational amplifiers with each half

electrically similar to the A741 except that offset null capability is？ not provided.

The high common-mode input voltage range and the absence of latch-up make these amplifiers ideal for voltage-follower applications. The devices are short-circuit protected and the internal frequency compensation ensures stability without external components.

The RC4558 is characterized for operation from 0 C to 70 C, and the RM4558 is character ized for ？？ operation over the full military temperature range of –55 C to 125 C.

2. FEATURES

◆ Continuous-Short-Circuit Protection

◆ Wide Common-Mode and Differential

◆ Voltage Ranges

◆ No Frequency Compensation Required

◆ Low Power Consumption

◆ No Latch-Up

◆ Unity-Gain Bandwidth . . . 3 MHz Typ

◆ Gain and Phase Match Between Amplifiers

◆ Low Noise . . . 8 nV?Hz Typ at 1 kHz

◆ Designed To Be Interchangeable With

◆ Raytheon RC4558 and RM4558 Devices

3. PIN CONFIGURATION

PIN No. Symbol I/O

Description 1 1OUT O 2 1IN– I 3 1IN+ I

Output 1 Inverting Input Pin 1 Non-Inverting Input Pin 1

- 57 -

PIN No. Symbol I/O

Description 4 VCC– I 5 2IN+ I 6 2IN– I 7 2OUT O 8 VCC+ I

Negative Power Supply Non-Inverting Input Pin 2 Inverting Input Pin 2 Output 2 Positive Power Supply

3.5.2 function introduction to PT2399

1. DESCRIPTION

PT2399 is an echo audio processor IC utilizing CMOS Technology which is equipped with ADC and DAC, high sampling frequency and an internal memory of 44K digital processing is used to generate the delay time, it also feature an internal VCO circuit in the system clock, thereby , making the frequency easily adjustable. PT2399 boast of very low distortion (THD<0.5%) and very low noise (No<-90dBV), thus producing high quality audio output .The pin assignments and application circuit are optimized for easy PCB layout and cost saving advantage.

2. FEATURES

◆ CMOS Technology

◆ Least External component

◆ Auto Reset Function

◆ Low Noise, No<-90dBV Typical

◆ Low Distortion, THD<0.5% Typical

◆ External Adjustable VCO

◆ Available in 16 pins DIP or SOP package

3. PIN CONFIGURATION

PIN No. Symbol I/O Description

1 VCC I Positive Power Supply 2 REF I Reference Power Supply 3 AGND I Simulative Ground 4 DGND I Digital Ground 5 CLK_O O NC 6 VCO O Voltage Controlled Oscillator 7 CC1 O External capacitor

- 58 -

PIN No. Symbol I/O Description

8 CC0 O External capacitor

9 OP1-OUT O External capacitor 1 output 10 OP1-IN I External capacitor 1 input 11 OP2-OUT O External capacitor 2 output 12 OP2-IN I External capacitor 2 input 13 LPF2-IN I Low pass filter 2 input 14 LPF2-OUT O Low pass filter 2 output 15 LPF1-OUT O Low pass filter 1 input 16 LPF1-IN I Low pass filter 1 output

3.5.3 function introduction to CD4051

1. DESCRIPTION The CD4051 is a single 8-channel multiplexer with three binary control inputs and inhibit input. The three binary control input signals select 1 of 8 channels to be turned on and connect it to the single

out.

The operating voltage is as 3 to 18V and quiescent current is as low as 5 µA max. (at Vpp=5V ).

2. PIN CONFIGURATION

PIN No. Symbol I/O Description

1 X4 I/O Channel selection port 4 2 X6 I/O Channel selection port 6 3 X I/O Channel selection output 4 X7 I/O Channel selection port 7 5 X5 I/O Channel selection port 5 6 INH I Inhibit 7 VEE I/O Negative Power Supply 8 GND I GND

9 C I Channel selection binary bit C 10 B I Channel selection binary bit B 11 A I Channel selection binary bit A 12 X3 I/O Channel selection port 13 X0 I/O Channel selection port 0

- 59 -

PIN No. Symbol I/O Description

14 X1 I/O Channel selection port 1 15 X2 I/O Channel selection port 2 16 VCC I Positive Power Supply

3. TRUTH TABLE

INH C B A ON SWITH

0 0 0 0 X0 0 0 0 1 X1 0 0 1 0 X2 0 0 1 1 X3 0 1 0 0 X4 0 1 0 1 X5 0 1 1 0 X6 0 1 1 1 X7 1 X X X NONE

3.5.4 function introduction to CD4052

1. DESCRIPTION The CD4052 is a dual 4-channel multiplexer with two binary control inputs and inhibit input. The two binary control input signals select 1 of 4 pairs of channels to be turned on and connect it to the

two outputs.

The operating voltage is as 3 to 18V and quiescent current is as low as 5 µA max. (at Vpp=5V ).

2. PIN CONFIGURATION

PIN No Symbol I/O Description

1 Y0 I/O Y channel selection port 0 2 Y2 I/O Y channel selection port 2 3 Y I/O Y channel selection output 4 Y3 I/O Y channel selection port 3 5 Y1 I/O Y channel selection port 1 6 INH I Inhibit 7 VEE I/O Negative Power Supply

- 60 -

PIN No Symbol I/O Description

8 GND I GND 9 A I Channel selection binary bit A

10 B I Channel selection binary bit B

11 X3 I X channel selection port 3 12 X0 I/O X channel selection port 0 13 X I/O X channel selection output 14 X1 I/O X channel selection port 1 15 X2 I/O X channel selection port 2 16 VCC I Positive Power Supply

3. TRUTH TABLE INH B A ON SWITH

0 0 0 X0 Y0 0 0 1 X1 Y1 0 1 0 X2 Y2 0 1 1 X3 Y3 1 X X NONE

3.5.5 function introduction to CD4053

1. DESCRIPTION

The CD4053 is a triple 2-channel multiplexer having three separate digital control inputs, A, B, and C and an inhibit input. Each control input selects one of a pair of channels which are connected in a single-pole double-throw configuration

The three binary control input signals select 1 of 2 pairs of channels to be turned on and connect it to the three outputs.

2. Features

The operating voltage is as 3 to 18V and quiescent current is as low as 5 µA max. (at Vpp=5V ).

3. PIN CONFIGURATION

PIN No. Symbol I/O Description

1 by I Y1 2 bx I Y0

- 61 -

PIN No. Symbol I/O Description

3 cy I Z1 4 c O Z 5 cx I Z0 6 INH I Enable 7 Vee I Negative Power Supply 8 Vss I GND

9 C I Select C 10 B I Select B 11 A I Select A 12 ax I X0 13 ay I X1 14 a O X 15 b O Y 16 Vdd I Positive Power Supply

4. TRUTH TABLE

INH B A ON SWITH

0 0 0 X0 Y0 0 0 1 X1 Y1 0 1 0 X2 Y2 0 1 1 X3 Y3 1 X X NONE

3.5.6 function introduction to SM79164

1. Description

The SM79164 series product is an 8 - bit single chip microcontroller with 64KB on-chip flash and 4K byte RAM embedded. It is a derivative of the 8052 micro controller family. It has 8-channel PWM build-in. User can access on-chip expanded RAM with easier and faster way by its ‘bank mapping direct addressing mode’ scheme. With its hardware features and powerful instruction set, it’s straight forward to make it a versatile and cost effective controller for those applications which demand up to 32 I/O pins for PDIP pack age or up to 36 I/O pins for PLCC/QFP package, or applications which need up to 64K byte flash memory for program data.

To program the on-chip flash memory, a commercial writer is available to do it in parallel programming method.

- 62 -

2. Features

◆ 2.4V ~ 3.0V For V Version

◆ Working voltage: 3.0V ~ 3.6V For L Version

◆ 4.5V ~ 5.5V For C Version

◆ General 8052 family compatible

◆ 12 clocks per machine cycle

◆ 64K byte on chip program flash

◆ 4096 byte on-chip data RAM

◆ Three 16 bit Timers/Counters

◆ One Watch Dog Timer

◆ Four 8-bit I/O ports for PDIP package

◆ Four 8-bit I/O ports + one 4-bit I/O ports for PLCC or QFP package

◆ Full duplex serial channel

◆ Bit operation instruction

◆ Industrial Level

◆ 8-bit Unsigned Division

◆ 8-bit Unsigned Multiply

◆ BCD arithmetic

◆ Direct Addressing

◆ Indirect Addressing

◆ Nested Interrupt

◆ Two priority level interrupt

◆ A serial I/O port

◆ Power save modes: Idle mode and Power down mode

◆ Code protection function

◆ Low EMI (inhibit ALE)

◆ Bank mapping direct addressing mode for access on-chip RAM

◆ 8 channel PWM function with P1.0 ~ P1.7

3. PIN CONFIGURATION

DIP Symbol I/O Define Name Function

O P_RST Liquid crystal reset 2 P1.1/T2 O P_RS Liquid crystal data 3 P1.2 I P_MICDET Microphone detecting input 4 P1.3 O P_E Liquid crystal read control bit 5 P1.4 O P_ADSELA Selection spectrum sampling control A

- 63 -

DIP Symbol I/O Define Name Function

6 P1.5 O P_ADSELB Selection spectrum sampling control B 7 P1.6 O P_ADSELC Selection spectrum sampling control C 8 P1.7 O P_GNB Spectrum gain control B 9 RST I RESET System reset

10 P3.0 O P_GNC Selection spectrum sampling control C

11 P3.1 I P_SELECT Mute/input detecting selection 12 P3.2 I P_ADINT0 Spectrum sampling interruption 13 P3.3 I P_REM Remote control detecting 14 P3.4 O P_CHARGE Spectrum sampling discharge control 15 P3.5 I P_DIST Distortion detecting 16 P3.6 I P_SEARCH Mute/input detecting 17 P3.7 O P_OKT OK sampling 18 XTAL2 O Crystal out Crystal out 19 XTAL1 I Crystal in Crystal in 20 GND I GND GND 21 P2.0 O P_SDA I2C data line 22 P2.1 O P_SCL I2C clock line 23 P2.2 O P_LT62446 LT62446 latched 24 P2.3 O P_LT4094 LT4094 latched 25 P2.4 O P_SCART SCART detecting 26 P2.5 O P_CLK Click line 27 P2.6 I P_ RLY Relay state input 28 P2.7 O P_GNA Selection spectrum sampling control A 29 /PSEN I Blank 30 ALE I Blank 31 /EA/Vpp I Vpp +5V pull up 32 P0.7 O P_D7 Liquid crystal data D7 bit 33 P0. 6 O P_D6 Liquid crystal data D6 bit 34 P0.5 O P_D5 Liquid crystal data D5 bit 35 P0.4 O P_D4 Liquid crystal data D4 bit 36 P0.3 O P_D3 Liquid crystal data D3 bit 37 P0.2 O P_D2 Liquid crystal data D2 bit

- 64 -

DIP Symbol I/O Define Name Function

38 P0.1 O P_D1 Liquid crystal data D1 bit 39 P0.0 O P_D0 Liquid crystal data D0 bit 40 Vcc I Vcc Vcc

3.5.7 function introduction to PT2308

1. DESCRIPTION PT2308L is a Class AB stereo headphone driver chip utilizing CMOS Technology specially designed for

portable digital audio applications. It is housed in an 8-pin DIP or SO package and is

functionally compatible with TDA1308. Pin assignments and application circuit are optimized for lower cost effectiveness and easy PCB Layout

2. FEATURES

◆ CMOS Technology

◆ Low Power Consumption

◆ Wide Temperature Range

◆ Excellent Power Supply Ripple Rejection

◆ High Signal-to-Noise Ratio, S/N=110dB

◆ Low Harmonic Distortion, THD= 0.001%

◆ Large Output Voltage Swing

◆ Low Supply Voltage Available (VDD=2V)

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 OUT1 O Output Pin R

2 IN1- I Inverting Input Pin R 3 IN1+ I Non-Inverting Input Pin R 4 Vss I Negative Power Supply 5 IN2- I Inverting Input Pin L 6 IN2+ I Non-Inverting Input Pin L 7 OUT2 O Output Pin L 8 Vdd I Positive Power Supply

- 65 -

3.5.8 function introduction to PT2222

1. DESCRIPTION

The PT2222is remote control transmitters utilizing CMOS Technology specially designed for use on infrared remote control applications .It is pin-to-pin compatible with NEC µPD6122 respectively. PT2222 is housed in 24 pins so and capable of controlling 64 function kens and 3 double keys. PT2222 may be paired with PT2225to construct a powerful remote control system.

2. FEATURES

◆ CMOS Technology

◆ Low Power Consumption (Vdd=2.0~5.5V)

◆ Pin-to-Pin Consumption with µPD6122

◆ Using SEL pin, PT2222can support 128+6 function codes

◆ Customer Code can be selected (please contact PTC for details)

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 K12 I Nc 2 K13 I Nc 3 K14 I Nc 4 K15 I Nc 5 K16 I Nc 6 K17 I Nc 7 REM O Serial data output 8 VDD I Positive Power Supply

9 SEL I GND 10 OSCO O Crystal out 11 OSCI I Crystal in 12 VSS I VSS 13 LMP Emission output indication 14 KI/O7 O Keyboard matrix line control 15 KI/O6 O Keyboard matrix line control 16 KI/O5 O Keyboard matrix line control 17 KI/O4 O Keyboard matrix line control 18 KI/O3 O Keyboard matrix line control 19 KI/O2 O Keyboard matrix line control

- 66 -

PIN No. Symbol I/O Description

20 KI/O1 O Keyboard matrix line control 21 KI/O0 Keyboard matrix line control 22 CCS I Address code control 23 K10 I Keyboard matrix row control 24 K11 I Keyboard matrix row control

3.5.9 function introduction to LM1875

1. Description The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for

consumer audio applications.

The LM1875 delivers 20 watts into a 4 ?or 8 ?load on ？？ ±25V supplies. Using an 8 ?load and ？ ±30V supplies, over 30 watts of power may be delivered. The amplifier is designed to operate with a minimum of external components. Device overload protection consists of both internal current limit and thermal shutdown.

The LM1875 design takes advantage of advanced circuit techniques and processing to achieve extremely low distortion levels even at high output power levels. Other outstanding features include high gain, fast slew rate and a wide power bandwidth, large output voltage swing, high current capability, and a very wide supply range. The amplifier is internally compensated and stable for gains of 10 or greater.

2. Features

◆ Up to 30 watts output power

◆ AVO typically 90 dB

◆ Low distortion: 0.015%, 1 kHz, 20 W

◆ Wide power bandwidth: 70 kHz

◆ Protection for AC and DC short circuits to ground

◆ Thermal protection with parole circuit

◆ High current capability: 4A

◆ Wide supply range 16V-60V

◆ Internal output protection diodes

◆ 94 dB ripple rejection

◆ Plastic power package TO-220

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 +IN I Non-Inverting Input Pin C

- 67 -

PIN No. Symbol I/O Description

2 -IN I Inverting Input Pin C 3 -VEE I Negative Power Supply 4 OUTPUT O Signal out C

5 VCC I Positive Power Supply

3.5.10 function introduction to TDA7265

1. DESCRIPTION

The TDA7265 is class AB dual Audio power amplifier assembled in the Multiwatt package, specially designed for high quality sound application as Hi-Fi music centers and stereo TV sets.

2. Features

◆ WIDE SUPPLY VOLTAGE RANGE (UP TO 25V ABS MAX.)？

◆ SPLIT SUPPLY

◆ HIGH OUTPUT POWER 25 + 25W @THD =10%, RL = 8 , V？ S = +20V

◆ NO POPAT TURN-ON/OFF

◆ MUTE (POP FREE)

◆ STAND-BY FEATURE (LOW Iq)

◆ SHORT CIRCUIT PROTECTION

◆ THERMAL OVERLOAD PROTECTION

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 -Vs I Negative Power Supply 2 OUT1 O Signal out SL 3 +Vs I Positive Power Supply 4 OUT2 O Signal out SR 5 MUTE I Mute control 6 -Vs I Negative Power Supply 7 IN2+ I Non-Inverting Input Pin SR 8 IN2- I Inverting Input Pin SR 9 GND I GND

10 IN1+ I Non-Inverting Input Pin SL

11 IN1- I Inverting Input Pin SL

- 68 -

3.5.11 function introduction to M62446

1. DESCRIPTION

The M62446FP is 6 channels electric volume controlled 3-wire serial data.

The IC is suitable for use in home-use audio systems and TV sets.

2. Features

◆ Electric volume: Volume level••••• 0dB ~ -79dB, - dB (1dB / step)？

◆ Tone control: Bass / Treble, 0dB ~ ±10dB(2dB / step)

◆ 4 Output ports: Built-in microcomputer interface circuit controlled by 16-bit serial data.

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 Out 4 O Source select control 4 2 Out3 O Source select control 3 3 Out2 O Source select control 2 4 Out1 O Source select control 1 5 AVdd I Positive Power Supply 6 SWin I SW Input 7 GNDS I SW GND 8 SRin I SR Input

9 SLin I SL Input 10 GNDC I C GND 11 Cin I C Input 12 GNDR I R GND 13 Rin I R Input 14 GNDL I L GND 15 Lin I L Input 16 BYPASSR O R bypass capacitance 17 BYPASSL O L bypass capacitance 18 LTRE O L treble capacitance 19 LBASS3 O L bass capacitance 20 LBASS2 O L bass capacitance 21 LBASS1 O L bass capacitance 22 RBASS1 O R bass capacitance

- 69 -

PIN No. Symbol I/O Description

23 RBASS2 O R bass capacitance 24 RBASS3 O R bass capacitance 25 RTRE O R treble capacitance 26 CR2 O R capacitance 27 CR1 I R capacitance 28 CL2 O L capacitance 29 CL1 I L capacitance 30 AVSS I Negative Power Supply 31 Lout O L out 32 Rout O R out 33 Cout O C out 34 SLout O SL out 35 SRout O SR out 36 SWout O SW out 37 AGND I AGND 38 DGND I DGND 39 LATCH I Select control 40 DATA I Serial Data input 41 CLK I Serial CLK input 42 DVDD I Digital Power Supply

3.5.12 function introduction to AT24C02

1. Description

The AT24C02 provides 2048 bits of serial electrically erasable and programmable read-only memory (EEPROM) organized as 256 words of 8 bits each. The device is optimized for use in many industrial and commercial applications where low-power and low-voltage operations are essential. The AT24C02 is available in space-saving 8-lead PDIP,

8-lead MAP, 8 lead TSSOP and 8-ball dBGA2 packages and is accessed via a 2-wire serial interface. In addition, the entire family is available in 2.7V (2.7V to 5.5V) and 1.8V (1.8V to 5.5V) versions.

2. Features

◆ Low-voltage and Standard-voltage Operation – 2.7 (VCC = 2.7V to 5.5V)

- 70 -

– 1.8 (VCC = 1.8V to 5.5V)

◆ Internally Organized, 256 x 8 (2K),

◆ 2-wire Serial Interface

◆ Schmitt Trigger, Filtered Inputs for Noise Suppression

◆ Bi-directional Data Transfer Protocol

◆ 100 kHz (1.8V) and 400 kHz (2.5V, 2.7V, 5V) Compatibility

◆ Write Protect Pin for Hardware Data Protection

◆ 8-byte Page (1K, 2K), Write Modes

◆ Partial Page Writes are Allowed

◆ Self-timed Write Cycle (5 ms max)

◆ High-reliability

– Endurance: 1 Million Write Cycles – Data Retention: 100 Years

◆ Automotive Grade, Extended Temperature and Lead-Free Devices Available

◆ 8-lead PDIP, 8-lead JEDEC SOIC, 8-lead MAP, 5-lead SOT23,

8-lead TSSOP and 8-ball dBGA2™ Packages

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 A0 I To Ground 2 A1 I To Ground 3 A2 I To Ground 4 VSS I To Ground 5 SDA I/O Serial Data input 6 SCL I/O Serial SCL input 7 TEST I/O Test port 8 VDD I Positive Power Supply

3.5.13 function introduction to L7805

1. Description

LM7805 is 5V voltage regulator, locates on power board in this player and is used to generate 5V stable

voltage.

2. Features

◆ Suitable for CMOS ,TTL, the other digital IC’s power supply

- 71 -

◆ Internal thermal overload protection

◆ Internal short circuit current limiting

◆ Output current in excess of 1 A

◆ Metal Fin is fully covered with Mold Resin

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 Input I Input +18V 2 Common I Ground 3 Output O Output +12V

3.5.14 function introduction to 7812

1. Description

LM7812 is +12V voltage regulator, locates on power board in this player and is used to generate +12

stable voltage.

2. Features

◆ Suitable for CMOS ,TTL, the other digital IC’s power supply

◆ Internal thermal overload protection

◆ Internal short circuit current limiting

◆ Output current in excess of 1 A

◆ Metal Fin is fully covered with Mold Resin

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 Input I Input +18V 2 Common I Ground 3 Output O Output +12V

3.5.15 function introduction to 7912

1. Description

LM7812 is +12V voltage regulator, locates on power board in this player and is used to generate +12

stable voltage.

- 72 -

2. Features

◆ Suitable for CMOS ,TTL, the other digital IC’s power supply

◆ Internal thermal overload protection

◆ Internal short circuit current limiting

◆ Output current in excess of 1 A

◆ Metal Fin is fully covered with Mold Resin

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 Input I Input -18V 2 Output O Output -12V 3 Common I Ground

3.5.16 function introduction to LM324

1. Description

The LM124 series consists of four independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.

Application areas include transducer amplifiers, DC gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM124 series can be directly operated off of the standard a 5 V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional g15V power supplies.

2. Features

◆ Internally frequency compensated for unity gain

◆ Large DC voltage gain 100 dB

◆ Wide bandwidth (unity gain) 1 MHz (temperature compensated)

◆ Wide power supply range: Single supply 3V to 32V or dual supplies ±1.5V to ±16V

◆　 Very low supply current drain (700 µA)–essentially independent of supply voltage

◆　 Low input biasing current 45 n A (temperature compensated)

◆　 Low input offset voltage 2 mV and offset current 5 n A

◆　 Input common-mode voltage range includes ground

◆　 Differential input voltage range equal to the power supply voltage

◆　 Large output voltage swing 0V to ±1.5V

- 73 -

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 Output 1 O Output 1 Pin 2 Input 1- I Inverting Input Pin 3 Input 1+ I Non-Inverting Input Pin 4 V + I Positive Power Supply 5 Input 2+ I Non-Inverting Input Pin 6 Input 2- I Inverting Input Pin 7 Output 2 O Output 2 Pin 8 Output 3 O Output 3 Pin 9 Input 3- I Inverting Input Pin

10 Input 3+ I Non-Inverting Input Pin

11 GND I GND 12 Input 4+ I Non-Inverting Input Pin 13 Input 4- I Inverting Input Pin 14 Output 4 O Output 4 Pin

3.5.17 function introduction to PT2315

1. Description

PT2315 is a two-channel digital audio processor utilizing CMOS Technology . Volume, Bass, Treble and balance controls are incorporated into a single chip. Loudness Function is also provided to build a highly effective electronic audio processor having the highest performance and reliability with the least external components. All functions are programmable using the IIC Bus. The pin assignments and application circuit are optimized for easy PCB layout and cost saving advantage for audio application. Housed in a 20-pin DIP/SO Package, PT2315is pin-to-pin compatible with TDA7315 and is very similar in performance with performance with the later.

2. Features

◆ CMOS Technology

◆ Least External Components

◆ Treble and Bass Control

◆ Loudness Function

◆ Input/Output External Noise Reduction System/Equalizer

◆ 2 Independent Speaker Controls for Balance Function

- 74 -

◆ Independent Mute Function

◆ Volume Control in 1.25 dB/step

◆ Low Distortion

◆ Low Noise and DC Stepping

◆ Controlled by IIC BUS Micro-Processor Interface

◆ Pin-to-Pin Compatible with TDA7315

3. PIN DESCRIPTION

PIN No.

1 REF O Reference Power Supply 2 VDD I Power Supply 3 AGND I AGND 4 TREB_L O L treble adjust capacitance 5 TREB_R O R treble adjust capacitance 6 RIN I R input 7 LOUD_R O R Loud adjust 8 NC NC

9 LOUD_L O R Loud adjust 10 NC NC 11 LIN I L input 12 BIN_L I L adjust capacitance input 13 BOUT_L O L adjust capacitance output 14 BIN_R I R adjust capacitance input

Symbol I/O Description

15 BOUT_R O R adjust capacitance output 16 ROUT O R output 17 LOUT O L output 18 DGND I DGND 19 DATA I Serial Data input 20 CLK I Serial CLK input

3.5.18 function introduction to 74VHC245

1. Description The VHC245 is an advanced high speed CMOS octal bus transceiver fabricated with silicon gate CMOS

technology. It achieves high-speed operation similar to equivalent Bipolar Schottky TTL while maintaining the

- 75 -

CMOS low power dissipation. The VHC245 is intended for bi-directional asynchronous communication between data busses. The direction of data transmission is determined by the level of the T/R input. The enable input can be used to disable the device so that the busses are effectively isolated. All inputs are equipped with protection circuits against static discharge.

2. Features

◆ High Speed: Tpd= 4.0 ns (typ) at Vcc= 5V

◆ High Noise Immunity: Vnih= Vnil = 28% Vcc (Min)

◆ Power Down Protection is provided on all inputs

◆ Low Noise: Volp= 0.9V (typ)

◆ Low Power Dissipation:

◆ Icc= 4 µA (Max) @ TA= 25qC

◆ Pin and Function Compatible with 74HC245

3. Truth table

Inputs

-OE T/–R

Outputs

L L Bus B Data to Bus A L H Bus A Data to Bus B

H X HIGH-Z State

H= HIGH Voltage Level L= LOW Voltage Level X= Immaterial Any unused bus terminals during HIGH-Z

State must be held HIGH or LOW.

4. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 T/–R I Transmit/Receive Input 2 A0 I/O 3 A1 I/O 4 A2 I/O 5 A3 I/O 6 A4 I/O

Side B Inputs or 3-STATE Outputs

7 A5 I/O 8 A6 I/O 9 A7 I/O

10 Nc

- 76 -

PIN No. Symbol I/O Description

11 B7 I/O 12 B6 I/O 13 B5 I/O 14 B4 I/O 15 B3 I/O 16 B2 I/O 17 B1 I/O 18 B0 I/O 19 -OE I Output Enable Input 20 Vcc I Power Supply

Side B Inputs or 3-STATE Outputs

3.5.19 function introduction to CD4094

1. Description

The CD4094BC consists of an 8-bit shift register and a 3-STATE 8-bit latch. Data is shifted serially through the shift register on the positive transition of the clock. The output of the last stage (QS) can be used to cascade several devices. Data on the QS output is transferred to a second output, Q′S, on the following negative clock edge.

The output of each stage of the shift register feeds a latch, which latches data on the negative edge of the STROBE input. When STROBE is HIGH, data propagates through the latch to 3-STATE output gates. These gates are enabled when OUTPUT ENABLE is taken HIGH.

2. Features

◆ Wide supply voltage range: 3.0V to 18V

◆ High noise immunity: 0.45 VDD (typ.)

◆ Low power TTL compatibility: Fan out of 2 driving 74L or 1 driving 74LS 3-STATE outputs

3. PIN DESCRIPTION

PIN No. Symbol I/O Description

1 STROBE I Store control 2 DATA I Serial data 3 CLOCK I Serial clock 4 Q1 O Bit 1 output 5 Q2 O Bit 2 output 6 Q3 O Bit 3 output

- 77 -

PIN No. Symbol I/O Description

7 Q4 O Bit 4 output 8 Vss I GND

9 Qs O Top Bit output 10 Qs’ O Non-Qs 11 Q8 O Bit 8 output 12 Q7 O Bit 7 output 13 Q6 O Bit 6 output 14 Q5 O Bit 5 output 15 Output enable I Output enable 16 Vdd I Positive Power Supply

- 78 -

Chapter Four Disassembly and Assembly Process

In order to know the structure of audio power amplifier AV225T easily, visibly and quickly, now each

key link of the disassembly and assembly process of the player is presented in means of pictures to

prevent users from incorrect operating and damaging elements. This player is composed by control

panel components, power amplifier board components, signal board components, volume board

components, power board components and MIC board components. So please operate according to

illustration strictly.

1. Disassembly and assembly process for the unit

DDD

CCC

BBB

AAA

(1) Use electric screwdriver to unfix screws in the joint

place

of upper cover and rear cover.

GGG

EEE

FFF

CCC

BBB

AAA

(2) Use electric screwdriver to unfix left and right hand side upper cover screws A , B and C.

BBB

(3) Take down upper casing.

BBB

AAA

(4) Pull down tuner flat cable A and video flat cable B.

- 79 -

CCC

DDD

AAA

BBB

B B B

C CC

(5) Use electric screwdriver to unfix screws A and B in the joint position of tuner and rear cover, and then unfix screws C and D in the joint position of video board and rear cover, then take them down.

AAA

BBB

AAA

CCC

(7) Use electric screwdriver to unfix screws A~E and screws A, B in the joint position of volume board and rear cover, and then take down volume board.

BBB

DDD EEE

(6) Pull down flat cable A, B and C on volume board.

AAA

(8) Pull down flat cable A E on signal board.

CCC

BBB

DDD

EEE

AAA

BBB

EEE

AAA

(9) Use electric screwdriver to unfix screws A, B, C, D and E in the joint position of signal board and rear cover, and then take down signal board.

CCC

DDD

AAA

BBB

DDD

CCC

(10) Pull down flat cable A, B C and D on power amplifier board.

- 80 -

(11) Use electric screwdriver to unfix screws A~D in the

point

position of bottom casing and power amplifier

board

heat radiator and screw E in the joint place with rear cover.

(13) Pull down flat cable A, B, C and D on power board.

(12) Use electric screwdriver to unfix screws A, B and C of power amplifier board, and then take down power amplifier board.

A A

(14) Use electric screwdriver to unfix screws A~D in the joint place of rear cover and output terminal of power amplifier output board (power board and power amplifier output board are both in one).

(15) Use electric screwdriver to unfix screws A~D of power board, and then take down power board.

(16) Use electric screwdriver to unfix screws on two sides of panel.

- 81 -

C C

(17) Use electric screwdriver or “+”-shaped screwdriver to unfix screws A~E in the joint place of panel and bottom casing.

(19) Use electric screwdriver to unfix screws of panel and MIC board, and then take down PCB board.

(18) Take hold of panel by right hand, fasten the bottom casing D with 4 fingers of left hand, hold the panel button bracket C with thumb and exert strength towards direction of arrow C until panel comes off from bottom casing clasp B, then exert strength towards direction of arrow C, left side panel falls off from bottom casing, and then right hand panel clasp falls off from bottom casing automatically.

(20) PCB board has been taken away.

2. Assembly process for whole unit

(1) Install panel, MIC board and use electric screwdriver to fix screws.

(2) Take hold of panel components and exert strength towards arrow direction (inward) until the clasp is f astened.

- 82 -

(3) Use electric screwdriver to fix screws in two sides of surface casing.

(5) Install power board and then Use electric screwdriver to fix screws A~D in the joint place of rear cover and output terminal of power amplifying output board (power board and power amplifying output board are both in one).

(4) Use electric screwdriver to fix screws A~E in the joint place of surface casing and bottom casing.

(6) Use electric screwdriver to fix screws of power board and insert flat cable A D to proper position.

(7) Install power amplifier board, and use electric screwdriver to fix screws A~D in the joint place of bottom casing and power amplifier board heat radiator.

(8) Use electric screwdriver to fix screws A, B, C of power amplifier board and then insert flat cable to proper position.

- 83 -

AAA

(9) Install signal board and use electric screwdriver to fix screw A of signal board.

AAA

CCC

(10) Use electric screwdriver to fix screws A, B, C, D of signal board and then insert flat cable to proper position.

BBB

DDD

(11) Install volume board and use electric screwdriver to fix screws A~D in the joint place of rear cover.

CCC

DDD

AAA

(13) Take hold of tuner by left hand, use electric screwdriver to fix screws A, B; take hold of video board by left hand, use electric screwdriver to fix screws C, D; insert flat cable respectively to proper position.

BBB

(12) Use electric screwdriver to fix screws A, B of volume board and then insert flat cable to proper position.

DDD

CCC

BBB

AAA

(14) Install upper cover, use electric screwdriver to fix screws of left, back and right sides; power on and test, and it is ok.

EEE

GG G

FFF

- 84 -

3. The process of changing LED back light source

(1) Use nail to enter the gap between LCD screen and upper edge of LED back light source, and then exert strength to put it up.

(3) After LCD screen falls off, take hold of forceps by right hand to move away flat cable holder of LCD screen, and the flat cable falls off automatically.

2 Take LCD screen with thumb and forefinger of left hand, press the whole board by right hand, take hold of the upper edge of LCD screen and exert strength towards arrow direction (leftwards).

(4) Use brand iron to weld away pin A and B of LED back light source.

(5) Press down LCD screen bracket clasp A, B with thumb and forefinger of right hand, exert strength with thumb towards direction of arrow A; after clasp A is away from PCB board, press down towards direction of arrow C, clasp A falls off and then clasp B falls off automatically.

(6) Separate LED back light source and LCD screen bracket clasp.

- 85 -

4. Process of assembling LED back light source

(1) Install LCD screen bracket clasp.

(3) Use brand iron to solder pin A and B of LED back light source.

(2) Install LED back light source.

(4) Take LCD screen flat cable between thumb and forefinger of right hand, insert it into flat cable holder, push up flat cable plug to proper position.

(5) Take hold of LCD screen by left hand and put down towards arrow direction.

(6) Press the LCD screen tightly.

- 86 -

Chapter Cinque

PCB board & Circuit diagram

Section One PCB board

5.1.1 Video Board

TC103

TC101

R106

V101

R107

R105 C101

TC104

C110T-2

N101

R103

2005.11.14

R101 R102

C103

R104

XC101

R108

C102

-12V V-B

V-A

INH DGND +5V

XS101

R109

- 87 -

5.1.2 Volume Board

C105

R162

R161

C106

R150 C113

R157

R170

R169

R168 R167

C146

C145

2110T-1

2006-01-17

C144

C150

R117

DVDL DVDR

R118

R116

C107

R115

N104

W14 N107

R146 R148 W21

R149 N108

W38 W39

W40 W41 W42 W43

C108

W44

XC101

VCDL VCDR

R112

R111

R113

R114

R144 R147

C112

R145

C111

C147

W22 R196 C114

W35 W36 W37

C138 C117

R138 R137

R139

C109

C121

W45

R155

C143

C122 C137

C136 C142

W46

L101

R177

R191

R178

W47

XS20

GND

R-1

C-1

SW1

L-1

SL1

DISP

GND

SR1

XC102

N103C110

C124

W59 W6

W12 R136 R124 R195 R133

W70 W66 W29 W30 W31

C131

R105

N102

C123

R106

W52

SR L

R103

R134 R135

R152

R132

W3 W2

N101

W15 W16

W17 W18 W19 W26

W58

N105

N106

R108

R109

R110

R130

W10

R107

R125

W11 R126

W13

W23

W24

R143 W20

R140 R141

R142

W28

W32 W33

W69

R159

C119

W34 R154 R153

C125

C132

R156

C126

C135 C134

W48

R176

R175

R174

C133

W50

C130 C129

W51

W49

C127 C128

C139

R165

C140

R164

C141

VD100 VD101

R163

XS22

-12V

+12V

D+5V

P_VST

DGND

P_CLK

P_VDA

P_TDO

R104

C120

C101C102

W53

P_TCE

R131

R129

R122

W25

W64 W68

W67 W27

R160

R158

W65

C154

C118

R121

V106

C103

R119RR120

W56

W61

C152

VD112

C115 R198

XP101

W63

W54

C149

W72

W62

W55

C116

C104

C153

W73

W71

W57 W60

-12V

D+5V

XJ2

C148

TUNER_L TUNER_R P_TDO P_DATA

B A INH GND

R197

XS19

+12V GND P_CLK P_TCE

GND

- 88 -

XS23 ~9V GND ~9V

XS6 +12V DGND

DGND

-12V XS102

P_D0 P_D1

P_D2

P_D3

P_D4

P_D5

P_D6

P_D7

XS103

P_RST P_RS

P_E P_REM LED

DGND DGND

D+5V

XS12

MIC2

AGND

MIC1

MIC-T

5.1.3 Signal Board

V109VD108

W17

C227

C211

C202

C228

N210

W59

V201

R210

W46 W42

C240

W63

R246

R211 R247 R220 R219 C221

C220

C143

W58 W57 W52

C234

W80

V110V111

W12 W50 W56 W54

C231

W34

XS101

W62

W64

W60

W61

W53

P_RLY DISP DSIT P_OKT P_CLK P_DATA

P_LT62446

P_LT4094

P_SCL P_SDA

GND D+5V GND GND

W48 W33

W55

VD206

VD205

R168

W71

R167

XP20

XP22

R153 VD202

OK-R DISP AGND AGND SW L-1 R-1 C-1 SR-1 SL-1

C206

C212

C207

C239

R258

C213

C214

W41

W18

R265 R275

W65

W70

W31

W72

R263

W73

W51

N207

N209

C138

W45

C144

W82

C250

VD204

N211

W28

VD203

C233

C232

R262

R254 R260

R232 R225

C251 R226

W79

R221 R224

R257 R255 R256

R223 R218

W30 W29

3215T-2 LLC 2005-06-15

W81

R235

W36

W19

W44

W32 W23

C248

W37

C242

R249

C243

R268

R284

C235

R264

C238

C249

R273

R234

R230 R248 R238

R274

R233

N205

N204

R253

C247

C216

W77

W74

W16 W20 W14

W21 W22

W27

C215

W83

XS9

XS13

VD104 VD103 VD102 VD100 VD101

N203

R222 R267

R229 R227

P_SCM

R239

P_RC

P_LRM

R250

R231

N208

R236

P_RLY

R145 R142 R113 R111 R112 R105 R104

AGND

R266 R261 R269 R271

R272 R215 R259 R270

R161

W10

R158

W69

V105 V104

R118

VD105 VD109 VD110 VD111

R252 R251

W68

C132

XP19

XS24

V103

R143

C131

C114

C113

C246

C245

C118

SW'C'SR'L'SL'R'AGND

W75

C125

C104

C108

FAN+

C122

C106

C119

R102 R140

R101 R137

R103 R108

FAN-

W66

C124

C121

N101

N100

W13

N102

AGND

R152

W67

R139 R109

R123

R121

R124

W43

SRQ1

XS25

C130

+12V

-12V P_REM P_D0 P_D1 P_D2 P_D3 P_D4 P_D5 P_D6 P_D7 P_RST P_RS

P_E

V202

W35

W78

R170

R171

VD106

VD107

C128

C203

W11

R209 R241

C205

V200

C237

VD200

XS100

R204

C200

C201

R207

C217 C218

C209

W38

N107

C129C134

C210

C229 C230

W15

R200

N201

R201

R208

W47

R213 R214

R217

W85 W84

C204

VD201

R242 R244

C236

R202

R240

C252

N202

W76 R216

C222

C219

C226 C225

C208

R106

R228

R243

C142

C137

R116 R110

W40 W39

R122

R132

R129

R163

R100

V102

C105 R133

R128

C103

C107

R134

C100

R120 R127

V108 R151

C115

R169

X100

C117

R154

C135

V106

W24

V107

C101

W49

R115

W26

W25

R162

V100

XC100

V101

C116

R157

C102

XJ2

- 89 -

5.1.4 Power Board

R103

V100

C121

XS1

05/12/2

5100-5 LJQ

XS2

XS3

TRANS

R101

R104

W14

C126

V103 R107 V101

C115 C114

FL100 T4AL250V

C102

R105

V102

C113

W22

W20

C109

C112

W13

R109 C120

C119

C118

C116 R106 VD110

R108 C117

VD111

R120 R115

R114

R119 R118

R113

R111 R116

W15 R117

R112

XL101

L103

C108

VD105

W11 W10

VD104

R121

L101

L104

VD103

R122

W16

W19

L102

L100

VD102

VD112

VD101

R110

W12

W8 W7

V105

C122

VD100

C124

V104

C110

C106

Y100

R100

VD107

C107

C125

XL100

W18

VD106

XP7

XP8

C111

VD108

VD113

C123

R102

SWM RLY0

P_RC OVER

L2 R2 C2 SL2 SR2 VC+ GND GND VC-

W21

XS4

C103

W17

FL101T6.3AL250V

FL102T6.3AL250V

C104 C105

- 90 -

C101

C100

5.1.5 Key Scan Board

V100

VD100

N101

VD101

VD102

VD1032VD104

2004-03-30

6228-1 LJQ

R100

R107

G100

S107 S101

S100

S106

C105

VD109

XP104

W9W11

N103

S103

S109

S102

S108

V G

C102

C104

XP105

R102 R101

R105

W10

W12

N100

C100

C101

C110

N102

S105

S111

S104

S110

C107

V101

R106

C103

C106

C109

VD107

VD108

VD106

R103

R104

XP102

C108

VD105

XP103

SOL

- 91 -

5.1.6 MIC Board

XP12

C100

MIC-DET GND

GND MIC1

9215T-1

2004-08-09

XJ1

R100

XP24

C102

+5V

R101

C105

R105

R106

C104

R104

R102

R103

MIC1

R108

C103

C106

R107

C101

XJ2

C107

R109R110

X100

- 92 -

5.1.7 audio power amplifying Board

C120

C110

W2 W14

V129

V114

W61

V112

W63

R113

R120

VD107

R117

VD104

C102 W69 W57 W51 W48

W75

V109

W43

W64

C103

R126

R119

R106

V132

R105

R109

V103

R128

W68

R118

W47

V108

SWM

V102

XS7

RLY0

C109

V105

R121

P_RC

C108

R111

C105

OVER

R112

V106 R114 R115

R108

C104

R104

R129

V107

R116

R107

W60

W76

V104

V111

R122

R124

V133

R110

C107

R130

W50

R123

V110

VD102 VD103

C106

R127

R125

VD101

R161

C121

C101

XS8

SL2

V113

W16

R101

R102

R103

V101V116R133

W45 W46

VC+

SR2

GND

R131

GND

P_RLY

V115

R132

P_RC

GND

P_LRM

P_CSM

W55

VC-

XP13

R162

C111

W67

V127

XP9

W77 W78

W66

W56

R147

C112

R143

R150

W13

V134

R149

V124

R136

C113

T4225T-0

2006 02 22

R135

W49

R156

R148

V118

R139 R151

W33 W59

V123

V117

R158

V120

W10

C118

R141

C119

C115

R142

R138

C114

V122

R146

R137

R134

V121

R144 R145

W11

V119

R159

V125

R153

R152

W12

V135

R154

2SA1964

R140

C117

W70

W62

R160

W58

VD105 VD106

C116

V126

W26

C125

C128

R163

V130

W37

C127

W18

W42

VD108

C154

T6.3AL250V

C159

V131

C124

C145

R181

N102

7912

R184 R183

N104

R167

SRQ1

I G

C149

C151

XP6

-12V

C146

W81

C147

W80

GND+12V

C148

C150

N1017812

VD10

W35

W20

W72

W41

V151

W36

W19

W54

R165

FL101

R171

W24

R166

C123

VD110

C126

V150

C122

VD109

R170

R169

R168

R180

T6.3AL250V

FL102

V128

R157

W39

W15

W40

R155

C141 C142

C156

R179

W65

C132

C155

W28

R175

C139 C140

W71

N106

W22

R178

W3 C134

C131

W74

R174

W53

C137 C135

W27

W21

C157

C130C129

VD112 VD114

VD111 VD113

XS5

W73

R172

C136

W52

R177

C144 C143

W31

R164

R173

R176

- 93 -

5.1.8 Surface layer of CPU Board

R127R128R129R126

C128

R144

R162

R152

R153 R163

C143

C144

R141 R146

R136 R151

R155 R160

R165

R158

R149

R143

R157

R148

C114

C122

C125

C131

R145

N104

C123

R159

R150

R142 R147

R137 R186

R156

C132

N108

C126

R161

R166

C136

C111

VD106

C141

C115

R125

R123

R122

R124

C127

C133

R118 R119

C124

C118

C130

C121

VD107 XP100

C139 VD119

VD117

R170 R169 C147

R172

R178 R177

N102

R183

C151

C112

RR100

R182

C102

L100

R180

R167

R181

C148

C152

L101

C105

C104

C101

C102

C107

R132

R131

C145

C113

XP104

C100

R100

1228-0

R135

C120

C117

C119

R140 VD109

VD110 VD108 VD111 VD112 VD113 VD114

C116

N105

R138

C135

R133

R139

R164

R134

C146

C134

N106

R130

C129

C140

R154

C106

R101

B100

C103

XP105

C108

C100

C155

C142

C110

VD115

R206

R225

N107

C137 C138

R224

C149R110

R185

R184

VD118

V105

R207

R223

R222

R115

R208

R220

R219

R218

VD116

V103

R203R204

C150

R117

V104

XP101

R116

R205

C109

N103

VD102

V102

DISP

P_RLY

DSIT

R104

R189

R113

VD103 VD101

V101

P_OKT

P_CLK

C108R112

R114

P_SCART

P_LT62446

R231

R230

P_LT4094

P_SCL

P_SDANCGND

R229

R228

R227

R199

R187

R217 R216

V100

R202

N101

R201

R179

R200

R215

C106

D+5V

R173

R212

R213

R198

GND

R174

R175

G100

GND

R111

R108

R109

R214

R197

P_E P_MT P_RS P_RST

7228-1

P_D7 P_D6 P_D5 P_D4

R107

P_D3 P_D2 P_D1 P_D0

R192

R195

P_REM

-12V +12V

R191

R196

R226

N100

R101

C105 R221

C103

R209

C104

R210

XP100

R100

C107

R211

- 94 -

5.1.9 Bottom layer of CPU Board

- 95 -

5.2.1 Video IN Board

Section Two circuit diagram

- 96 -

VCD

DVD

VOUT

XC101

AV3

1 2

R101 100

R102 100

R108 22

5 6

R107 10k

VCD DVD

TC103

220u/16V

+5V

R105

100

VOUT

R109 1

V101

A1015

R106

22K

TC101

100u/16V

13 14 15 12

1 5 2

N101 CD4051

XCOM

X1 X2 X3 X4 X5 X6 X7

C102

103

VDD

VSS

INH

VEE

A(0) B(1) C(2)

16 8

+5V

R103 22

11 10 9

R104 100

DGND INH V-A V-B

-12V

XS101

1 2 3 4 5 6

CON6

+5V

C101

C103

103

TC104

103

220u/16V

BBK AV225T Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual