Acer H15AAX User manual

15-inchLCD Monitor
H15AAX
Service Manual

Service ManualVersionsand Revision
Copyright
Copyright2002LiteOnTechnologyCorp.
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TechnologyCorp.
H15AAX(AL502)ServiceManual.
Printed in Taiwan.
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LiteOnisaregisteredtrademarkofLiteOn
TechnologyCorp.
Allothertrademarksarethepropertyoftheir
respectiveowners.
No. Version Release Date Revision
1. 1.0 Jan. 31, 2002 Original release

CircuitDescription
H15AAX (AL502)

CircuitDescription
H15AAX (AL502)
Page1
1. Audio circuit (Circuit diagramsMain PWB)
1.1Audioinput
Theaudiosignalinputreceivedfromtheaudioinputterminal(JK011)isappliedtotheamplifierI001 of4(L-
CH)and 9(R-CH)through thelow-pass filterconsisting ofR040,R041,R042,R043,C040 and C041.
Inthisamplifier,controlsofVolumeandmuteareconducted.Theaudiosignalcontrolledatthepin6determines
theattenuationofoutputoftheamplifiers.Sincethen,thesignalisoutputtothejackP003.
1.2Audiooutput
TheaudiosignalisoutputfromP002 outputterminaloftheAudioblocktotheinternalspeakersystem.
2. Powersupply (Circuit daigramsMAINPWB)
2.1LinefilterconsistsofC801,T801,C802,C803,C804.Iteliminateshighfrequencyinterference tomeetEMI’s
requirement.
2.2Rec &Filter:
BridgediodeD801 convertsACsource intopulsedDC.ThispulsedDCissmoothedand filteredby C805.
R802 isanNTC(negativethermalcoefficient)resistor,usedtoreduce inrushcurrenttobewithinsaferange.
2.3Powertransformer:
T802 convertsenergy forsquarewavefrompowersource C805 tosecondarysidetogenerate+12Vand +5V.
2.4Output:
ThesquarewavefromT802 isrectifiedby D809,D810,thenfilteredby C817,C822 togenerate+12Vand
+5Vrespectively.
2.4.1A5VpowersupplyforLCDmodule,CPUand logicisgeneratedfromthepowersource.
2.4.2I308 :3-terminalregulator
A3.3VpowersupplyforI306 analog isgeneratedfromthe5Vsource.
2.4.3I308 :3-terminalregulator
A3.3VpowersupplyforI306 digitalisgeneratedfromthe5Vsource.
Q302,Q303 ON/OFF controlforLCDModule
ON/OFF controlisperformedforpowerON/OFF and alsoforthepowersaving sequence.
2.5Driver:
Q803 driveT802 fromPWMcontrolofI801 forpowerconverted.
2.6FB:
NegativefeedbackCKTconsistsofphotocouplerI802and adjustableregulatorI803.Itcanmaintainoutput
voltages+5Vand +12Vatastablelevel.
2.7PWM:
2.7.1Start:Whenpoweristurnedon,Q801 conductsduetobiasfromC805 andR805,R803.C807 ischargeda16
volt and astarting currentabout0.3mAtopin7ofI801.I801 startstooscillateand outputsapulsetrain
through pin6todriveQ803.
2.7.2OPP :WhenQ803turnson,C805 suppliesalinearlyincreasing trianglecurrentthrough theprimaryinduc
tance ofT802 tothedriverQ803,once thepeakvalueofthiscurrentmultipliedbyR811 exceeds1volt,pulse
trainwill beshutdownimmediatelytoprotectQ803,T802frombeing burnedout.
2.7.3Regulation :If outputvoltage+5Vgoesup,theRterminalofI803 getsmorebias,accordinglyphototransis
torand photodiodeflowsmorecurrent.Thevoltageofpin2goesup too,making thepulsewidthofpin6to
becomenarrower.Sotheoutputvoltage+5Vwill bepulleddowntoastablevalue.

CircuitDescription
H1 5A AX (AL502)
Page2
2.7.4OVP :If +5Vgoesup too much,theinducedvoltageon pin4ofT802 becomeslargealso.Supposethatit is
over18 volts,ZD801 conducts,pin3ofI801 ispulledup over1volt.Thepulsetrainatpin6goesdownto
zero,shutting Q80 3 off immediately.
2.7.5SCP:If outputterminalisshorttoground,phototransistordoesnotconduct,hence Q806 doesnotconduct
either.Thenoscillation ofI801 isstop,shutting Q803 off immediately.
3.On-screencircuit (Circuit diagramsMainPWB)
I3 00 Embededfunctio n.
On-screenmenu screenisestablishedand theresultantdataareoutputfromI300 (Circuit diagramMAINPWB).
4.Videoinputcircuit (Circuit diagramMAINPWB)
TheAC-coupledvideosignalisusedtoclamptheblacklevelat0V).
5.Definition converterLSIperipheralcircuit (Circuit diagramMAINPWB)
I301 MRTV2gmZAN1isthedefinitio n A/DconverterLSI.
Theanalog R,G,Bsignalinputenteredfromthevideoinputcircuit isconvertedintothedigitaldataofvideo
sig nalthro ugh theincorporatedA/Dconverter.Basedon thisconversion,thisdevice per formsinterp olat ion
during pixelextension.Thesource vol tageforthisdevice is3.3Van d thesystemclockfrequencyis12MHz.
Thewithstand voltagelevelfortheinputsignalvoltageis3.3Vand 5V.
6.Systemreset,LEDcontrolcircuit (Circuit diagramMAINPWB)
6.1Systemreset
Systemresetisperformedby detecting therising and falling ofthe5Vsource voltageatI302.
6.2LE Dco ntrolcircuit
Green/amberislit withthecontrolsignaloftheLEDGREENand LEDAMBERsignalpin43,4 2 fromI303
(Circuit diagramMAINPWB).
7.E2PROMforPnP(Circuit diagramMAINPWB)
H15AAU / H15AAR Power Board Block Diagram
Line Filter Rec.
&
Filter
Power
Transformer
Output Rec. & Filter
PWM Driver
FB

Circ uitDescription
H15AAX (AL502)
Page3
8.E2PROM(Circuit diagramMAINPWB)
DatatransferbetweenI30 4 and CPU(Circuit diagramMAINPWBpage4/7(I303)iseffectedthro ugh theIIC
busSCL(pin9)and SDA (pin8)ofI300 orSCL(pin42)and SDA pin39 ofI301.Thedatatobetransferredto
eachdevice arestoredinI304.
l I300 controldata.
l OSDrelatedsetting data.
l Othercontroldataforservice menu.
9.CPUcircuit (Circuit diagramMAINPWB)
I3 03 (MTV312M64)(SM89516C2 5)or(W78E62BP-40 )funct ion sastheCPU.
Thesou rce voltageforthedevice is5.0Vand thesystemclockfrequencyis12MHz.
9.1Detectio n ofPOWERswitchstatus
TheCPUidenti fiestheON statusofthetwopowersupplies.Theidentification ismadewhenthepowersupply
isturnedoff.Forexample,ifthepowersupplyisturnedoff withthePOWERswitch,thePOWERswitchmustbe
turnedon whenactivating thepowersupplyagain.If thepowersupplyisturnedoff by pullin g outthepower
cord,thenthispowersupplycanbeturnedon by connecti ng thepo wercord,wi thoutpressin g thePOWER
swit ch.
9.2Displaymod eidentificat ion
9.2.1Fun ction s
(1)Displaymodeident ificat ion
l Thedisplaymodeofinputsignalisidentifiedbasedon Table1,and according tothefrequencyand polarity
(HPOL,VPOL)ofhorizontalorverticalsyncsignal,presence ofthehorizontalorverticalsyncsignal,and the
discriminati on sig nal(HSYN C_DETECT,VSYN C_DETECT).
l Whenthemodehasbeenidentifiedthrough themeasurementofhorizontaland verticalfrequencies,thetotal
numberoflinesisdeterminedwithaformulaof“Horizontalf requency/Vertic alfrequency=Totalnumber
oflines.“Finalident ific ation canbemadeb y examining thecoincidence oftheob tainedfig urewiththe
numberoflinesforthemodeident ifiedfromthefrequ ency.
l Whenthedetectedfrequencyifthesyncsignalhaschanged,thetotalnumberoflinesshouldbecountedeven
through i t isrgeidentifiedfrequencyinthesamemode.Then,it isnecessarytoexaminewhetherthepreset
valuefortheverti caldisplayposition ofItem4-3hasexceededthetotalnu mberofli nes.If exceeded,a
maximumvalueshouldbesetup,whichdoesnotexceedtheverticaldisplayposition ofItem4-3.
(2)Out-of- ran ge
Thisout-of-rangemodeisas sumedwhenthefrequencyofthehorizontal/verticalsignalisasspecifiedbelow.
l Verticalfrequency:Below50Hzorabove85Hz
l Horizontalfr equency:Below24 KHzorabove75 KHz
(3)Powersavemode
Thepowersavemodeisassumedwhenthehorizo ntal/verticalsig nalsareasspecifiedbelow.
l If thereisno horizontalsyncsignalinput.
l If thereisno verticalsyncsignalinput.
l If thehorizontalsyncsignalisoutsidethemeasuring rangeofI300.
l If theverticalsyncsignalisoutsidethemeasuring rangeofI300.

Circ uitDescription
H1 5A AX (AL502)
Page4
Table1
Attention:
1.Whenresolutionbeyond1024 x768isinputted,resolutionisloweredwithDownscaling to1024 x768,and
indicated,and OSDshouldindicateOUTofRange.
9.3UserControl
9.3.1RelatedportsofI303
Port
Pin No.
I/O
Signal name
Function Remarks
P1.5 7IPOWER Power switch input Power ON , OFF
control
P1.1 3IDOWN switch input ( ) key
P1.0 2IUP switch input ( ) key
P1.3 5I - - switch input ( - ) key
P1.2 4I++ switch input ( + ) key
Polarity
Mode
No Resolution
H-freq
(KHz)
Band Width
(MHz) H V
1. 247 VGA 720 x 350 70Hz
31.47
28.322 +-
2. 102 VGA 720 x 400 70Hz
31.47
28.322 -+
3. 103 VGA 640 x 480 60Hz
31.47
25.175 - -
4. 182 MAC 640 x 480 66Hz 35 32.24 - -
5. 173 VESA 640 X 480 72Hz
37.86
31.5 - -
6. 109 VESA 640 X 480 75Hz 37.5 31.5 - -
7. 104 VESA 800 x 600 56Hz
35.16
36 + +
8. 116 VESA 800 x 600 60Hz
37.88
40 + +
9. 110 VESA 800 x 600 75Hz
46.88
49.5 + +
10. 117 VESA 800 x 600 72Hz
48.08
50 + +
11. 108 MAC 832 x 624 75Hz
49.72
57.283 - -
12. 118 VESA 1024 x 768 60Hz
48.36
65 - -
13. 217 SUN 1024 x 768 65Hz
52.45
70.49 - -
14. 157 VESA 1024 x 768 70Hz
56.48
75 - -
15. 141 VESA 1024 x 768 75Hz
60.02
78.75 + +

CircuitDescription
H15AAX (AL502)
Page5
9.3.2Fun ction s
Controliseffectedforthepush-switchestobeusedwhentheuserchangestheparameters,inordertomodifythe
respec tivesettin g values.Whethertheswitchhasbeenpressedisidentifiedwiththeswitchinputlevelthatis
turned“L”.
Eachswitchinputportispulledup atoutsideofASIC.
EachparameterisstoredintheEEPROM,thecontentsofwhichareupdatedasreq uired.
9.4Controlofdefinition converterLSII300.
9.4.1Portsrelatedtocontrol
Pin No. I/O Signal name Function
159 IIRQ interrupt signal
5I/O SCL serial clock
6I/O SDA serial data
9.4.2Fun ction s
Majorfunction ofI300 areasfollows:
(1)Ex pansion ofthedisplayscreen.
(2)Timing controlforvarioussignaltypes.
(3)Power -supplysequence (LCDpanel).
9.5I2Cbuscontrol
9.5.1RelatedportsofI303
Port Pin No. I/O Signal name Function
P1.7 14 OSCL IIC bus clock
P1.6 13 I/O SDA IIC bus data
9.5.2I2C-control ledfun ctio ns
Thefollowing fu nctionalcontrolsareeffectedby I2C.
(1)ControlofEEPROMI30 4 forparametersetting.

Circ uitDescription
H1 5A AX (AL502)
Page6
9.6PowerON seq uenc e
WhenthePOWERswitchispressed,thePOWEROFF signalisturned“H”.Whenthis“H”potentialisdetected,
theCPUbeginstoestablishtherespe ctivepowersuppliesaccording tothesequence shownbelow.
POWER
PPWR
D-SHCLK
INV_EN
LED
DATA

Circ uitDescription
H15AAX (AL502)
Page7
9.7PowerOFF sequence
WhenthePOWERswitchispressedwhilethepowersupplyisON,thePOWERONsignalisturned“H”.When
tshownbelow.his“H”potentialisdetected,theCPUbeginstoturnoff therespectivepowersuppliesaccording
tothesequence
POWER
PPWR
D-SHCLK
INV_EN
LED
DATA