Acer AC901 User manual

19 -inchCRTMonitor
Acer AC901
S

AC901
Page 5
2 Product Specifications
2-1Specifications
Note:Above specificationsaresubjecttochange withoutpriornotice.
Picture Tube 19-inch, (18-inch visual image area) sloted mask, 90 degrees deflection, dot type black matrix, medium short persistence
phosphor, dark tint, non-glare/ anti-static screen,
0.26 mm dot pitch
Scanning Frequency VGA, Super VGA, 1024x768@75/85 Hz, 1280x1024@85 Hz
Maximum Resolution 1600 dots (H) x 1200 lines (V) @75Hz refresh rate
Display Area 350 mm (H) x 262 mm (V) typical
Display Characters 80 char. x 60 rows on a 10 x 10 matrix
Display Colors Analog
Input Unlimited Colors
Synchronizatin Signals Separate Sync: horizontal/vertical, TTL, positive or negative
Synchronization
Frequencies Horizontal : 30 to 96 kHz Vertical : 50 to 160 Hz
Signal Connectors 15-pin, D-shell connector
Video Signals Analog : 0.7 Vp-p, RGB positive
Power Input 120 Watts (maximum) AC rated voltage, 100VAC to 240VAC,
200VAC to 240VAC for PNST/PNSL models
Misconvergence Center Area : <0.3 mm; Corner Area : <0.4mm
User Controls
Power On/Off, Contrast, Brightness, Horizontal Size,
Horizontal Position, Vertical Size, Vertical Position,
Pincushion, Trapezoid, Pin Balance, Parallelogram, Rotation,
Color temperature, Language, Display Frequency, Degauss,
Recall, H. Moire, V. Moire
Service Controls PWB-1596/1598 : power voltage adjust (VR801)
focus 1 , focus 2
Preset Modes 10 (see Table 2-2. Timing Chart)
Environmental
Considerations Operation temperature : 5oC to 35oC ambient Operation Humidity : 20% to 80% ambient
Storage temperature : -40oC to 65oC ambient
Storage Humidity : 5% to 95% (non-condensing)
Altitude : up to3000m above sea level

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2-2SignalCablePinConnections
Table2-1.SignalCablePinAssignment
Pin Signal Pin Signal
1Red video 9+5V
2Green video 10 Digital Ground
3Blue video 11 Ground
4Ground 12 SDA
5* Ground 13 H-Sync
6Red ground 14 V-Sync/VCL
7Green ground 15 SCL
8Blue ground
Note:*Thispinisusedforselftestdetection.Connectthispintogroundatthe PCend.

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2-3Timing Chart
Thissectiondescribesthe timingsthatthe computerindustryrecognizesasstandardforcomputer-generated
videosignals.
Table2-2.Timing Chart
Seperate Sync
Horizontal
Video
C
D
E
Sync
A
B
F
Vertical
Video
I
J
Sync
G
H
L
K
H.Parameters:
A:Period B:Blanking Time
C:Sync WidthD:BackPorch
E:Active TimeF:FrontPorch
V.Parameters:
G:Period H:Blanking Time
I:Sync WidthJ:BackPorch
K:Active TimeL:FrontPorch
Mode 1 2 3 4 5 6 7 8 9 10
H. Dots 640 720 640 832 800 1152 1024 1600 1280 1600
V. Dots 480 400 480 624 600 870 768 1200 1024 1200
H-freq (kHz) 31.47 37.927 43.27 49.725 53.67 68.681 68.67 75 91.146 93.75
Sync Polarity - - - - +-+-+ +
A period us 31.78 26.366 23.11 20.11 18.631 14.561 14.561 13.333 10.971 10.667
B Blanking us 6.356 6.085 5.33 5.586 4.409 3.04 3.725 3.457 2.844 2.765
C Sync us 3.81 2.028 1.556 1.117 1.138 1.28 1.016 1.185 1.016 0.948
D B.P. us 1.907 3.042 2.22 3.91 2.702 1.44 2.201 1.877 1.422 1.501
E Active us 25.42 20.282 17.78 14.524 14.222 11.52 10.836 9.877 8.127 7.901
F F.P. us 0.636 1.014 1.556 0.559 0.569 0.32 0.508 0.395 0.406 0.316
V-freq (Hz) 59.94 85 85 74.55 85 75.062 84.99 60 85 75
Sync Polarity -+- - +-+-+ +
G Period ms 16.68 11.759 11.76 13.414 11.756 13.322 11.765 16.667 11.761 13.333
H Blanking ms 1.43 1.213 0.67 0.864 0.578 0.656 0.582 0.667 0.527 0.533
I Sync ms 0.064 0.079 0.069 0.06 0.056 0.044 0.044 0.04 0.033 0.032
J B.P. us 1.02 1.107 0.578 0.764 0.503 0.568 0.524 0.613 0.483 0.491
K Active us 15.25 10.546 11.09 12.549 11.179 12.667 11.183 16 11.235 12.8
L F.P. us 0.35 0.026 0.023 0.04 0.019 0.044 0.015 0.013 0.011 0.011

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2-4PowerSaving Function
Note:The monitorwill bedriven into“PowerSaving”modebythe controlsignalfromthe display
controller,asindicatedbythe amber-colorpowerLED.
Table2-3.PowerSaving Function
State Power
Consumption LED
Light
ON <120 watts Green
Active
OFF <3 watts Amber
The powersaving stateswill bekeptuntil acontrolsignalhasbeen detectedorthe keyboardormouseisactivated.
The recoverytimefromActive OFF statebacktoONstateisaround10seconds.
2-5TCOVersion (Optional)
The monitormeetsthe TCO99,NUTEKenergy saving,electricandmagneticfieldrequirements.
2-5-1TCO99 Version (Optional)
The emissionfrommagneticandelectricfieldmustcomplywiththe limitsspecifiedbythe SwedishBoard
forMeasurementandTesting,commonlyknownasMPR1990 recommendations.Theselimitsare
summarizedinthe Table2-4.
Table2-4.TCO99 Requirements
VLF/TCO ELF/TCO
Magnetic Field 25 nT 200 nT
Electric Field 1 V/m 10 V/m
Frequency Range 2~400 kHz 5~2000 Hz
Value RMS RMS
Distance 30 cm 30 cm
Electrostatic
Potential +/- 500 V +/- 500 V

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The monitorisdesignedwithselectedCRTandcarefullyroutedwiresaroundCRT,makesureexactlythe
samerouting schemeisusedwhen doing CRTreplacement.
The TCO99 schemeisforinternationalandenvironmentallabelling ofpersonalcomputers.The labelling
schemewasdevelopedasajointeffortbythe TCO(The SwedishConfederationofProfessionalEmploy
ees),Naturskyddsforeningen (The SwedishSocietyforNatureConservation)andNUTEK(The National
BoardforIndustryandTechnicalDevelopmentinSweden).
1)`Scope
TCO99 touchesonergonomicqualities,emissions(electricalandmagneticfields),energy efficiency and
ecology (withdemandsforenvironmentaladaptationforboththe productandthe productionprocessesat
the manufacturing plant).
2)EnvironmentalRequirements
The monitorabidesbythe environmentaldemandsconcerning restrictionsonthe presence anduseof
heavy metals,brominatedandchlorinatedflameretardants,CFCs(freons),andchlorinatedsolvents,
among otherthings.The monitorisalsorecyclable.
3)Energy Requirements
The monitoralsofollowsthe energy requirementsthat, afteracertainperiod ofinactivity,the monitor
shall reduce itspowerconsumptiontoalowerlevelinone ormorestages.
4)Others
The monitormeetsthe strictenvironmentaldemandsforthe reductionofelectricandmagneticfields,
physicalandvisualergonomicsandgood usability.
Table2-5.TCO99 VisualErgonomics
Feature Standard Description
Linearity 1% or less Difference in length of columns or rows compared to the
corresponding lengths through the center of the monitor.
Display Luminance 100 cd/m2 (at least)
Luminance
Uniformity 1.5:1 or less The ratio is between the max to min luminance within the whole active area.
Color temperature
variation ? u'v'0.01≦
Reclections from
casing 20%/30glass≧ ≦ The reflection ration is on cabinet & table.

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3 Control Location and Functions
3-1FrontPanel
3-2FrontPanelKeysFunctions
1.FunctionKey:Display the mainmenu,andexitthe adjustmentscreen andsave adjustments.
2.DecreaseKey:Scroll across mainmenu,highlighting controltobeadjusted.Decreasevalue ofselected
control.Togglebetween ContrastandBrightness adjustmentscreens.
3.IncreaseKey:Scroll across mainmenu,highlighting controltobeadjusted.Increasevalue ofselected
control.Togglebetween ContrastandBrightness adjustmentscreens.
4.SelectKey:Press once todisplay adjustmentscreen.Press again,forsomecontrols,totogglebetween
controlsshowninpairsonmainmenu.
5.PowerLED:Display differentmodes(ON,OFF)ofthe monitorbyshowing differentcolorforeach
mode.
6.PowerON/OFF:Toturnthe monitorON andOFF.
3-3AdjustmentProcedure
1.Press (6)key toturnonthe monitor.
2.Atnormalcondition,press (1)onthe frontpaneltoactivatethe on-screen manager(OSM)menu.
3.Toselectausercontrol,press (2)or(3)key repeatedlyuntil the controlishighlighted.
4.Toadjustthe value foraparticularcontrol,press (4),then press the (2)or(3)key toobtainthe desired
value.Thereareafewparametersthatdo notrequireany adjustment, likeManualDegauss,Memory
Recall.
5.Somecontrolsaregroupedinpairsonthe mainmenu.Press (4)key totogglebetween them.
6.Tosave youradjustmentsandexitscreen,press (1)key.The menu will automaticallyclearoutfromthe
screen ifnokeysarepressedwithin30 seconds.
Note:Toenterthe “InternalAdjustment”mode,press (1)&(4)keyssimultaneouslythen press (6).
(1) Function Key
(2) DecreaseKey
(3) IncreaseKey
(4) Select Key
(5) Power LED
(6) Power ON/OFF
(1) (2) (3) (4) (5) (6)
1
2

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4 Operation Theory
Thisisafullydigitalcontrolledmulti-sync colormonitorthatiscompliantwithDDC1/2BPlug andPlay
VESAstandardandoffersthe following mainfeatures.
4-1MainFeatures
1.Simplifieddesign withminimumcomponents.
2.The NOVATEKNT68P65AU processor-- thathasI2Cbuscontrolledgeometriccorrection,contrastand
brightness-- offersthe functionsfor:(a)Contrast, (b)Brightness,(c)H-size,(d)H-position,(e)V-size,(f)
V-position,(g)Pincushion,and(h)Trapezoid,(i)PinBalance,(j)Parallelogram.
Inaddition,italsooffersmorefunctionsas:(a)Sync.processor,I/PandO/P,(b)Mute,(c)Powersaving
off, (d)Powersaving override,(e)DDC2B,(f)I2CBusforauto-alignmentthrough signalcable(g)CS
switching forlinearityandsizecompensation,(h)High voleage adjustment, (i)G2voltage adjustment.
3.Storesupto10factorypresetmodesandoffers6usermodes.Thereare18 functioniconsinOSD.They
arecontrolledby
1
2
keysonthe frontpanel.
4.PowerfulPHILIPS TDA4841 andTDA4863 presentthe following usefulfunctions:(a)Pincushion,(b)
Trapezoid,(c)V-Position,(d)V-Size,(e)Vertical’s“C”and“S”correction--factoryadjust,(f)Pincushion’s
V.positioncorrection,(g)Cornercorrection-- factoryadjust, (h)Pincushionunbalance correction--
factoryadjust, (i)Parallelogramdistortion-- factoryadjust, (j)Moirecancellation,(k)X-ray protection,
and(l)Full horizontalandverticalautosync capability.
5.Softwarecontrolledautoshutoff functionactivatediffH<=29 kHzandfH>=96 kHz.
6.Full range AC inputandsimplifiedline filterdesign.
4-2MicrocontrolSection
1.ThismonitorusesNOVATEKNT68P65AU CPU.Itcontainsa8-bitCPUcore,256 bytesofRAMused
asworking RAMandstackarea,24k bytesofOTP ROM,14-channel8bitPWMD/Aconverter,2-
channelA/Dconvertersforkey detectionsaving I/Opins,internalH.sync andV.sync signalsprocessor
providing modedetection,andan I2Cbusinterface.When H/Vsync through D-Subsignalcableenterpin
41 andpin42,the CPUperformsfrequency /polaritydetectionandcalculateandsendtoH/Vsync OUT.
Then CPUreadsthe datafromI703andtransfertodevice 4841andsomeDACinCPU,above operation
takesabout500 ms.
2.Thereallows10factorypresetmodesand6usermodes.Thereare8functions,Contrast, Brightness,H.
Size,H.Position,V.Size,V.Position,Pincushion,andTrapezoid,all controlledbyOSDiconwhich can
beadjustedbyuser.
3.The pin25 andpin26areusedforATE function.When CPUreceivesC6asslave address,itwill operate
inATE modewhich isusedforauto-alignment. Afteralignmentthe datawill bestoredinI703.
4.The usercontrolparametersareselectedbyOSDicons,through
1
2
keys,they aredetectedby
sensing the voltage through R710,R759,R713,R714,R709,R711,R760 topin16 and17 ofI701.
4-3Deflection Section
1.I2C-- autosync deflectioncontrollerisTDA4841.
2.The TDA4841 isahigh performance andefficientsolutionforautosync monitors.All functionsare
controllablebyI2Cbus.SDA andSCLsignalscoming frommicroprocessorfeedtopin19 andpin18 to
controlall functions.

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4-3-1 Horizontal Section
1.The oscillatorisdriven bythe currentsinR472 andR468.Theminimumoscillatorfrequency isdetermined
byR472 andthe maximumfrequency isdeterminedbyR468.
2.Horizontalsync goesintopin15through R494.Andhorizontalflybackpulsegoesintopin1through R479
andbypass filterC445 fromEmitterofQ407 andC412,C433,C411,R419,C456,R421,D413 forAFC
loop.
3.Horizontaldriver(pin8)outputtoQ401 viaC401,Q401 switching todrive T401 provideIB1/IB2current
then turnon/off Q402 andswitching the yokecurrent.
4-3-2Vertical Section
1.Verticalsync goesintopin14 through R493.
2.The free running frequency isdeterminedbyR470 andC442.
4-3-3Vertical O/Psection
1.The differentialoutputcurrentsfrompin13 ofVout1andpin12 ofVout2can bedirectlycoupledtothe
verticaldeflectionboosterpin3andpin2ofTDA4863.
2.TheTDA4863 hastwooutputstageswhich arecurrentdriven inoppositephaseandoperateincombination
withthe deflectioncoil inahalfbridge configuration.
3.ThisICispoweredbythree setsofpositive voltage.(+13Vatpin1,37Vatpin8,-13Vatpin6)
4-3-4E-W/Trapezoid and H. Width Controls
1.The scan currentisdeterminedbyB+(the voltage ofC413)thatisobtainedfromstepdowncircuit
output. StepdowncircuitincludeQ404,T402,D407.
2.I401 TDA4841 pin6(BDRV)will drive the stepdowncircuittochange H.width.
3.EWDRV(pin11)providesacompleteEWdrive waveformincluding parabola,cornerandtrapezoid
correctionandfeedtoBIN(pin5ofI401)togetagood controlforpincushion/trapezoid/corner.
4.The topandbottomcornercorrectioncan beadjustedseperately.
4-3-5X-Ray Protection
1.ToavoidX-ray hazard,aDC voltage generatedatpin6ofFBTandrectifiedbyD107,C111 anddivided
byR476,R477 andR478 comeintopin2ofTDA4841.
2.Ifthisvoltage ishigherthan 6.39 V,then TDA4841 will beactivatedtofloatHUNLOCK(pin17),H.
DRV(pin8),BDRV(pin6),VOUT1(pin12),VOUT2(pin13).Afterthatall deflectioncircuitstop
working.
4-3-6Blanking and Brightness
1.The verticalblanking signalcomesfromI401 pin16 andverticalsync.Thesetwopulsescombine into
Q542 andQ541.ThissignalfeetsintoT501 pin24.
2.Inprotectionmodeoroutofrange ormodechange mutesignalwill turnhigh andturnonQ107.
G2voltage will drop from600Vto250V.
3.The brightness iscontrolbyI2Cbus.The outputpinsareI501 pin14,pin15,pin16.

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4-3-7ContrastSection
1.ContrastiscontrolledbyI701 through I2CbustoI501 (LM1267)directly.
2.Beamcurrentisdetectedthrough T101 (FBT)pin7,D106,C109,Q102,R108,R121,R122 tocontrol
I501 pin22 voltage.When I501 pin22 voltage dropsbelow5V,the ABLfunctionwill happen.
4-3-8Dynamicfocuscircuitry
The dynamicfocusisappliedtoimprove the cornerfocusperformance,itincludeshorizontalandvertical
dynamicfocus.
1.VerticaldynamiccomesfromI401 pin32 andisamplifiedthrough C105,Q101,C137,andfeedtoFBT
dynamicfocuspinsR133,R132,Q101.
2.Thisamplifierneed200Vvoltage supply,itcomesfromFBTpin8andrectifiedthrough L102,D101,and
C102.
4-4PowerSupplySection
4-4-1AC Rectifier
The circuitcan accept90 Vto264 VAC inputthrough D801 bridge diodesandC808filtering togetDC 126
V~364 VforpowerconversioninT802.
4-4-2Line Filter
ItconsistsofC801,C802,C803,C816,C820,C823,T801,T804 andmeetsEMIregulation.
4-4-3PowerLEDStatus
1.The LEDhas3leadswithcommoncathodetoemitgreen andambercolorlightfordifferentpower
saving states.
2.Normal:Green light
3.Off Mode:Amberlight
4-4-4 Auto Degaussing
When S801 turnson,pin27 ofI701 will sendasignaltoQ802 andturnsonRL801 fordegaussing.After4
seconds,itwill turnoff RL801 automatically.
4-4-5 PWMControl
1.StartUp
The I801 (KC3843B)getspowerfromR846,Q821,R849,R848,D826,D828,D822 andpin7voltage
reaches8Vforstarting up.The I801 startsoscillationat22 kHz,sawtoothonpin4andpin6outputto
drive Q803/T802.Once Q803 switching on,D806,C804 setupan 15 VtokeepI801 working through
D821 auxiliaryvoltage.
2.Regulation
The DC O/Pvoltage isproportionaltothe auxiliaryvoltage,soI801 pin2sensesthe feedbackvoltage
fromthe dividerR802,R823,VR801 andR820tocomparewiththe built-in2.5voltsreference voltage for
erroramplifieroperation.Finallypin6can modulatethe differentdutycyclebyVR801 setting toachieve
regulationpurpose.

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4-4-6Synchronization
1.NormalMode
The sync pulsefromFBT(31 kHz~95 kHz)viaR812,R831,C815,R826,D824,C814 andR816 topin4
ofI801 tokeepI801 synchronizedwithhorizontalsync inputfrequency.
2.PowerSaving Modes:Off mode
BecausethereisnopulsefromFBT,sothe free-run frequency isdecidedbyR817 andC814 andthe
SMPS worksat22 kHz.
3.Override
The horizontalfree run frequency isabout62.5kHzunderoverridecondition,SMPS issynchronizedto
thisfrequency.
4-4-7O.V.P.
Ifthe auxiliaryvoltage ishigherthan zenervoltage ZD807 (20 volts)andmakespin3ofI801 higherthan
1V,pin6dutycycleislimitedtohave the OVPactivated.
4-4-8O.P.P.
The excess currentofT802 through R813,R814,R834,C813,R865 andR864 can develop enough voltage
onpin3then limitthe powerdeliveredbecausethe pin6dutycycleislimitedtoo.
4-4-9 High VoltageGeneration with F.B.T.
1.The H.VgenerationcircuitcombinesT101 F.B.T.withI101 TL494/KA7500 PWMcontrolcircuit.
2.When I101,Vcc(pin12)reachesat12V,pin5,6getsafreerun sawtoothwaveformabout25KHz,and
approximately5.7Vp-p,when voltahe atpin15 ishigherthan pin16 (5Vreference)then releasepin3to
becontrolledbypin1feedbacksignalandcomparewithpin5tooutputPWM.
3.HFLB1isusedtotriggerpin5viaQ112,tosynchronizethe deflectioncircuit.
4.PWMoutputwilldrive Q116 &T101 togereratehigh voltage (26KV),T101 pin11,15 becomesDC/AC
feedback,withthe voltage linktoI101 non-inverting inputpin1tostabilizeH.V(26KV)andVR101 can
beadjustedtocontrolH.Vvalue.
5.When X.R.Poccur,the hunlockwill keephigh topull downI101 pin2andshutdownPWMoutput.
4-5VideoAmplifierSection
1.RGBsignalinputsareterminatedbyR501,R531 andR561 then pass through the coupling capacitors
C501,C531 andC561 toIC501 LM1267 preamplifier.
2.The amplifierRGBsignals(0~4Vpp)areadjustedbyI2CbusfromI501,pin23 isforclamppulsewhich
comesfrompin16 ofTDA4841.
3.The videooutputstagesareamplifiedbyI901(LM2465).The RGBcathodescutoff areadjustedbyI2C
buscontrolbyinternalicon.
4.Underoverridecondition,“CHECKSIGNAL”will showuponthe screen.
4-6OSD(OnScreen Display)Circuit

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1.The I502NT6827-00002 isOSDIC.The OSDsignalsareworkedbypositiveverticalpulsefromI701 pin
32 thatgoesthrough R554 toI502 pin10,andpositive horizontalpulsefromHFLB1through R527toI502
pin5.CPUI701 pin27,28 (I2Cbus)transfersinformationtoI502 pin7,8.
2.The OSDR.G.Bsignalsandblanking signalareterminatedatI502 pin15,14,13,and12 feedintoI501
pin1,2,3,and4,then the OSDpictureappears.

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5 Alignments and Adjustments
Thissectionofthe service manualexplainshowtomakepermanentadjustmentstothe monitorsettings.
5-1GeneralAdjustments
5-1-1AdjustmentConditions
a)PowerSupply
ApplyAC 115 Vor220 V
b)Warm-upTime
The monitormustbepoweredonfor15 minutesbeforestarting any alignment,butrequires30 minutesof
warm-uptimeforconvergence adjustment.
c)SignalInput
1.Video:RGBAnalog,0.7Vp-p,positive
2.Synchronization:HorizontalandverticalTTL signal,separate,positive ornegative
3.All adjustmentsshouldbemadeusing asignalofFH=91 kHz,FV=85Hz,unless otherwisedefined.
5-1-2EquipmentRequired
The following equipmentsarenecessaryforadjustmentprocedures:
1.Volt-ohm-Ameter(SanwaFD-750Corequivalent)
2.30 kVhigh voltage probe(HP34111A)
3.Oscilloscope(TEK2235 orequivalent)
4.MinoltaColorAnalyzerII
5.Signalgenerator(COMPAQPCwithproperdisplay cardsorChroma2250//2225)
6.Screwdriver
5-1-3Switching PowerSupply and RegulatorAdjustment
a.The regulatedB+controlhasbeenpresetinthe factoryandneedsnoadjustment. However,ifany repair
ismadeonthe powersupplysection,the following readjustmentproceduresarerecommended:
1.Allowthe monitortowarm-upforabout15 minutes.
2.ApplyXGA (1280x1024 @91 kHz/85 Hz)signaltothe monitor.
3.ConnectaDC voltage metertoTP001 end,andadjustVR801 for10.7+0.1VDC
4.Ifafuseisbroken during adjustment, remembertoreplace itwiththe exactsametypeoffuse.
b.Ifnecessary,followthe following procedurestoenterthe factorymode.
1.Press both
1
key and
2
key simultaneouslythen powerOn.
2.Afterturnthe poweroff,monitorwill gobacktonormalmode.

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5-2AlignmentProcedures
5-2-1 High Voltage Adjustment
CONDITION
Display image :Crosshatch pattern
5-2-2Screen and White Balance Adjustment
CONDITION
Press
1
and
2
buttonssimultaneouslywhen switching the power“On”.
Display image :Novideo
PROCEDURE
1Rastercolorsetting
1-aAdjustHV icontosethigh voltage =26KV.
1-bAdjustG2icontosetG2at600 ±5V
1-cSetBrightness iconmaximumto40%
1-dSelectOSDicontoR.G.B.cutoff
1-eSetGgun cutoff to0.5±0.15 FL
1-fAdjustR/Bcutoff togetx=283 ±5,y=297 ±5,Y=0.6±0.2FL
1-gSetBrightness tocutoff ,getY=0.01 ~0.03 FL
1-hSetBrightness tominimum.
CONDITION
Display image :50 mm x50 mm whiteblockpattern
PROCEDURE
2 65000Kcolortemperaturesetting
2-aSetBrightness tocutoff andContrastto75 Value
2-bMove cursoronOSDtochoosecolortemperatureicon.
2-cPress
2
key toGgainthen adjustGgain=70 value,then adjustB,Rtox=313±5,y=329±5.
2-dCheckx=313±5,y=329±5.
3 93000Kcolortemperaturesetting
3-aMove cursoronOSDtochoosecolortemperatureicon.
3-b.Press
2
key toGgainthen adjustGgain=75 value,then adjustB,Rtox=283±5,y=297±5.
3-cAdjustContrastmax.tosetY=38±2FL
3-dCheckx=283±5,y=297±5.
3-eAdjustContrastmin.tosetY=1.0FL.
4Full whiteABLsetting

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CONDITION
Display image :full whitepattern
4-aSetBrightness tocutoff andContrasttomaximum.
4-bMove cursortochooseABLinsidecontrasticon.
4-cAdjustABLtosetY=32±1FL
4-dRepeatall the proceduresin5-2-2sectionuntil the bestwhitebalance isobtained.
5-2-3FocusAdjustment
CONDITION
Display image :“e”characterpattern
PROCEDURE
1.SetBrightness tocutoff andContrasttomaximum.
2.Adjusttop VRatT101 (staticfocusVR)tomakeverticalline clear.
3.AdjustcenterVRatT101 (dynamicfocusVR)tomakehorizontalline clear.
4.Repeatabove procedurestogetbestfocus.
5-2-4DynamicfocusAdjustments
1.HorizontaldynamicfocussetHf=370V±10 Vinphase(comparewithVcpsignal).
2.VerticaldynamicfocussetVf=145V±10Vinphase.
5-2-5StaticConvergence Adjustments
Staticconvergence involvesalignmentofthe red,blue andgreen linesinthe centerarea ofthe display.
Note:The monitorrequires30 minuteswarm-uptimeforconvergence adjustment.
CONDITION

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Display image :Crosshatch pattern
Warm-upTime:30 minutes
PROCEDURE
1.SetBrightness andContrasttodisplay awell-definedpattern.
2.Ensurethe convergence magnetringsarecorrectlypositionedonthe CRT.
Figure4-1.Convergence Magnetsonthe CRT
+
87 65 4 3 2
10
1
11
CRT
FRONT
P
9
1) Setup Bolt 2) Bow Magnet 3) Band 4) 4-Pole Magnet
5) Spacer 7) Spacer
9) Holder 6) 6-Pole Magnet 8) 2-Pole Magnet 11) Tabs10) Band
3.Rotatethe individualringsof4-poleconvergence magnetsbychanging the spacing between the 2tabsto
converge the verticalredandblue linesatthe centerofthe screen.
4.Rotatethe pairofringsof4-poleconvergence magnetsbymaintaining spacing between the 2tabsto
converge the horizontalredandblue linesatthe centerofthe screen.
5.Rotatethe individualringsof6-poleconvergence magnetsbychanging the spacing between the 2tabsto
converge the verticalred,blue andgreen lines.
6.Rotatethe pairofringsof6-poleconvergence magnetsbymaintaining spacing between the 2tabsto
converge the horizontalred,blue andgreen lines.
7.Repeatthe stepsfrom3~6until the bestconvergence isobtained.
Figure4-2.4-poleand6-poleMagnetsMovement
Note:The 4-polemagnetsandthe 6-polemagnetsinteract, making dotmovementcomplex.
Blue Red
Blue
Red
Red/
Blue Green
Red/
Blue
Green
4-pole magnets
movement
6-pole magnets
movement

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5-2-6Degaussing
Degaussing isrequiredwhen poorcolorimpurityappearsonthe screen.Thismonitorusesan automatic
degaussing circuitthatisactivatedwhen the powerison.The automaticdegaussing will befullyfunctional
againafterthe monitorhasbeen inoperationfor20 minutes.
The degaussing effectisconfinedtothe picturetubesince the coilsaremountedatthe backofthe tube.
Shouldany partofthe chassisorcabinetbecomesmagnetized,itisnecessarytodegauss the affectedarea
withamanualdegaussing coil.
5-2-7Manual Degaussing
1.Applyline voltage tothe degaussing coil andmove itinarotarymotionoverthe front,sides,andtopofthe
monitor.The coil shouldbekeptaway fromthe rearofthe monitortoavoiddamaging the magneticneck
components.
2.Slowlyrotateandmove thecoil away fromthe monitortoabout6feetbeyondthe pointwherenoeffect
onthe CRTwill benoticeable.
Forproperdegaussing,itisessentialthatthe fieldbegraduallyreducedbymoving the coil slowlyaway from
the monitor.The degaussing coil mustneverbeshutoff ordisconnectedwhilenearthe monitor,asthiswould
introduce astrong fieldinsteadofcanceling the effectofthe stray fields.

AC901
Page 21
6 Troubleshooting
6-1NoRaster
Measure
voltage of B+ at
T402 pin 2 on
PWB-MAIN
No Raster
Check voltage of
cathode, heater, Grid
1, Grid 2, etc. Check I401
Normal
(137 V, 91kHz) High (175 V or more)
Yes
Short Circuit
at load?
0 V
No
Check
D801,T801,
R804, T804,
F801
Check I801,
Q803, R814,
R813, ZD807,
ZD801, R811,
R861, D825
Check DC B+ line,
Q402, Q404
Yes
Check
AC I/P on
C808
No

AC901
Page 22
6-2OSDAbnormal
Put on
I502
Replace them
No
Check I502
missing?
Check R516,
R526, R527
OK?
OSD Abnormal
Yes
No
No
Replace it
Yes
Yes
Check J516,
R556 OK?
Replace I502

AC901
Page 23
6-3Function Key Abnormal
Put on
I701, I703
Replace X701
No
Check I701 and
I703 missing?
Power
ON/OFF again and
check X701, oscillator
OK?
Function Key Abnormal
Yes
No
No
Replace I703 or do
ATE again
Yes
Replace I701 and check
uP OK?
Yes
Check
I703 EEPROM content
OK?
No
Replace I705
Check
pin 5 of I701
is 5V?
Replace I701 Yes
Check
R732, C713
Yes
No