JBL 6810 User manual

Professional
Video
Products
FIELDSERVICEGUIDE
MODEL6810AND6820
VIDEOPROJECTOR
CAUTION!
USEANISOLATIONTRANSFORMERWHENSERVICINGTHIS
JBLInternational
8500BalboaBlvd.
Northridge,CA91329
[phone]
SAFETYNOTICE!
Rev.4.28
JBL
ANYPERSONATTEMPTINGTOSERVICETHISCHASSISMUST
FAMILIARIZEHIMSELFWITHTHECHASSISANDBEAWAREOF
THENECESSARYSAFETYPRECAUTIONSTOBEUSEDWHEN
SERVICINGELECTONICEQUIPMENTCONTAININGHIGH
VOLTAGES.

SubjectCONTENTPage
ServiceandSafetyPrecautions3
Introduction
UsingtheTroubleshootingCharts3
Non-ServiceableAdjustments3
TheTwoGroundSystem4
IsolationProtection4
TVSystemOverview4
AdjustingtheNewCRT4
TS10PTuningSystemBlockDiagram5
6810SignalRowBlockDiagram6
Electro/MechanicalFocusingProcedure7
AdjustmentProcedures7
NonserviceableAreas7
HorizontalOscillator7
AGC7
VerticalHeight7
ComputerTextCentering7
WhiteBalance/GrayScaleTracking8
VideoProcessorPanel8
LuminancePeakingControl8
TroubleshootingtheChassis8
PowerSupplyPanel9
DeflectionPanel9
AllBandTuner10
TS10TunerInterfacePanel10
TS10PController11
Audio/VideoInput/OutputModule11
Stereo/SAPDecoderModule11
SoundProcessingModule12
StereoPowerAmplifier12
VideoProcessorPanel13
CombFilterModule13
CRTDrivePanels14
HorizontalDelayModule14
ConvergencePanel14
TroubleshootingtheChassis
DeadSet- Chart 1 15
NoAudio,NoVideo- Chart2 15
NoAudio- Chart3 15
NoAudio,NoVideo- Chart4 16
NoVerticalDeflection- Chart5 16
PictureRolls- Chart6 16
SetShutsDown- Chart7 17
TunerVoltages- Chart8 17
OneColorMissing- Chart9 17
ColorBandAtBottomOfPicture- Chart1018
SetDoesNotConverge- Chart1118
PincushionErrorTop/BottomAndSides- Chart1219

Servicing AndSafetyPrecautions
1. Becarefulofshockhazardwhenoperatingprojector with thecoveroff.
2. Useanisolationtransformerwhen servicing theunitto protect boththesetandthe test
equipmentelectronics.
3. Always wearsafetyglasseswhenservicing CRT's.
4. Donotremovesolid state devicesfrom circuits whilethesetisturnedon.
5. Donot operate thesetforlongperiodsoftimewhentheshutdown circuit defeated.
6.Becertain that eachvoltage test is made fromthecorrectground.
7. Becertain that all grounds,groundstraps,andwiresareproperlyconnectedto
protect thesetelectronicsandtheuserfrom shock.
8. Always checkforshockhazardaftercompletionofchassisrepairs.Referto Service Manual
for proper "SafetyCheck"procedures.
Introduction
This Service GuideincludesinstructionfortheModel6810Projection TV circuitry. Itincludes
adjustmentproceduresplussymptomandtroubleshootingchartstolocateeitherfaultypanels,
socketedsolid state devices,ormodules.A signal flow blockdiagramandpanel/modulelayout
diagramsareincluded.
Before exchangingpanelsormodules,itisimportanttomakesomepreliminarychecks.These
checksinclude:operationofthecustomercontrols,cableconnectionsandplugseating,acces-
sory connection,antennaconnections,andoperational mode checks.On sets usingon-screen
characters,observationofthescreenisveryusefulintroubleshooting.If these checksdonot
locatetheproblem,thentheCovermustberemovedanda visual inspection made of all wiring
harnessesandconnectors. Look forbroken wires, overheatedcomponents,openfuses,etc.If
the visual checkandpreliminaryinspection does notlocatethemalfunction,usethe
TroubleshootingCharts,listedbysymptomand page numberintheSymptomIndex.
NOTE: Useanisolationtransformerwhentroubleshootingthischassis!The
unithastwogroundsystems.Itisveryimportanttousethecorrectgroundfor
test equipmentwhenmakingmeasurements.
Non-serviceableAdjustments
The followingnon-serviceableadjustmentsare critical andshouldnotbeadjustedinthe field:
RP1 B+ControllerandRP2HVAdjustonthePowerSupplyPanel,and RP1 OverVoltage
SenseontheDeflection Panel. (Theseadjustmentsaresealedtopreventmis-adjustment.)
R7AGC Delay IF Module
LI 31.5kHzOsc Horiz. Osc.Module
RP1RGB Centering Horiz. Osc.Module
RP2 Height Horiz. Osc.Module
RP3V. Linearity DeflectionPanel
C70 Color Osc. VideoProcessor
RP1 Luminance PeakVideoProcessor
RP4 SubBrightnessVideoProcessor
RP5 PeakContrastVideoProcessor

UsingtheTroubleshootCharts
Whenusing theTroubleshootingCharts,determinethesymptombyscreenobservationand
controlaction.ChecktheSymptomIndexandfind thesymptomthatmostcloselydescribesthe
problem. ThepageindicatingthatkindofproblemhastheTroubleshootChartdealingwithit.
theTroubleshootChartslistadjustments,panelsandmodulestobechecked.Ifacheckresults
ina symptomchange,locatethenewsymptomintheIndexandfollowthechartdirections.
TwoGroundSystem
ThetwogroundsystemusedonthePowerSupplyPanelandDeflectionPanelare"AC"or
"Hot"groundand"Signal"or"Cold"ground.TestpointsTP3andTP9aremeasuringequip-
mentgroundsusedwhencheckingaclineconnectedcircuits."Signal"or"Cold"groundtest
pointsTP1andallshieldingonthesignalplugstopanelsandmodulesareusedfortestequip-
mentgroundswhenmeasuringcircuitsconnectedto"Signal"ground.
Isolationbetween"Hot"groundand"Cold"groundisdevelopedbyPowerTransformerTl,HV
TransformerT4,andOpticCoupler IC1 onthePowerSupplyPanel.HorizontalDriveTrans-
formerTlandHorizontalOutputTransformerT2providetheisolationontheDeflectionPanel.
IsolationProtection
ItisimperativeanIsolationTransformerbeusedonthetwo-groundsystemtoprotectthetest
andmeasuringinstrumentsaswellasthesetelectronicsfrom mis-polarizedaclinecordplugs.
TVSystemOverview
WhenthePowerplugisconnectedtotheacline,Stand-byvoltageisfedtotheTS10PCon-
troller,Figure1, and regulatedto5VdctokeeptheMicrocomputeralive.A Power-Onkey
pressattheRemoteTransmitteroron-setKeyboardtunesthesettoChannel3,selectsthe
AntennaRFInput,andplacestheaudiosystemintheMonauralmode.TheTS10PController
displayson-screengraphicstoidentifythemode.TheMicrocomputeracceptsalldatafromthe
keyboard.Ifthechanneldataisincorrect,theTS10Pdisplayblinkssixtimesandontheseventh
blinkrevertstothepreviouschannelnumber.Incompletechannelnumbersreverttotheprevious
channeliftheseconddigitisnotenteredwithineightseconds.Zerocancellationisusedonall
numbersbelow10.Volumeiscontrolledin64steps.Soundismuteduntilthechannelistuned
andwhentheMutekeyispressedontheRemoteTransmitter.PresstheRemoteTransmitter
MutebuttonorVolumeUpbuttontoun-mute.
Figure2 showsthePanelandmodulefunctions,interconnectcables,plugs,andjacks.The
heavierlinesidentifythesignalflowfromtheRFSwitchertotheStereoSpeakerterrninalsand
theRed,GreenandBlueCRTs.Switchingsignals,controlvoltages,andotheroperationalvolt-
agesareshownwithlighterlines.
Adjustinga newCRT
AfterinstallinganewCRT,checkthepositionofthenewCRTrasteragainsttheCrosshair
patternoftheothertwoCRTsusing thefollowingprocedure.
1. Placethealikemagneticringtabstogether.
2. Rotatetheyoketopositionthecrosshairpatternstogether.Ifthepatternsdonot
match, adjustthemagneticringtabstopositionthecrosshairpointstogether.
3.UseaCrosshatchpatterngeneratortochecktheoverallconvergence,andtouch
upconvergenceifnecessary.

Figure1 - TS10TuningSystemBlockDiagram

Figure2-SignalFlowBlockDiagram

Electro/MechanicalFocusingProcedure
1. SettheBrightness,Picture,andColorcontrolsforbestpicture.
2. Loosenthewingnutsoneachlens.
3.AdjusttheelectricalFocuscontroltoeachCRTforsharpestscanlinesviewedon
thetubefaceplatethroughthelens.
4. Mechanicallyfocuseachlensforsharpestpictureviewedonthescreen.
AdjustmentProcedures
Non-serviceableAreas
Thenon-serviceableareasfoundonthePowerSupplyPanelandDeflectionPanelarecircuits,
componentsandcontrolswhicharenottoberepairednoradjusted.Shouldamalfunctionoccur
intheseareas,thefaultisrepairedbyreplacingthepanel.
HorizontalOscillator
The31.5kHzOscillatorontheHorizontalOscillatorModuleisadjusted as follows:
1. Jumperthetwopinsat TP301. Thepicturewillrollverticallyandhorizontally.
2. AdjustoscillatorcoilLIuntilthepicturerollsslightlyorstands still.
3.Remove the jumperfrom TP301. Thepicture shouldlock.Ifthepicturedoesnot
lock,checkthersymptomindexforthetroubleshootingchartdescribingthecondition
viewedonthescreen.
AGC
TheAGCcontrolislocatedinsidetheIFModule.Itisaccessedthroughtheholeinthetopof
themoduleidentifiedasDelayedAGC.Use a plastichexalignmenttooltoreachtheAGC
controlshaft.
1. Tunethesettoa strongTVchannel.
2. Rotatethecontrolwhilewatchingthescreen.
3.Atthepointwhenthepicturebecomesnoisy,rotatethecontrolintheopposite
directionuntilthenoisedisappears.
4. Checktheotherstrongchannelfornoise,andreadjustAGCasrequired.
VerticalHeight
TheVerticalHeightcontrol(RP2)islocatedontheHorizontalOscillatorModule.TheVertical
Linearitycontrol(RP3)islocatedbelow RP1 ontheHorizontalOscillatorModule.
1. WithaCrosshatchorpictureadjusttheHeightcontroltofilloutthepicturearea.
2. AdjusttheVerticalLinearitycontroltocorrectnonlinearityinthepatternorpicture.
3.Readjustbothcontrolsasrequiredforbestpicturelinearity.
ComputerTextCentering
Ifthecomputertextareaisoff-center,lifttheconvergenceboardtoaccesstheHorizontal
OscillatorModule.TheRGBCenteringadjustment(RP1)islocatedonthelowerright.
1. PlugthecomputercableintotheRGB"D"Connector,locatedintheJackPlate.
2. SelectthecomputerinputwiththeRGBbuttononthecustomercontrolpanel.

3.Observetheviewingscreenandadjust RP1 tocenterthetextontheraster.
WhiteBalance/GrayScaleTracking
TheCRTDriveControls(RP1ontheCRTDrivePanels)andScreenorG2Controls(onthe
G2/FocusAssemblybetweentheredandgreenlenses)areadjustedusingthefollowingsteps.
1. SetthePicture,Sharpness,andBrightnesscontrolsatmidrange.
2. TurntheColorfullydown.
3.SetallCRTDriveControlstomaximum(CW)andtheScreenstominimum(CCW).
4. Tunethesettoa snowychannel.
5.MoveServicePlugJ216ontheDeflectionPaneltotheserviceSet-Upposition.
6.AdjusteachG2controltoobtaina faintline(whichappearswhitewithallthreecolors).
7.ReturntheServicePlugtothenormalposition.
8.Checkgrayscaletracking.AdjusttheBrightnesscontrolfrom maximumto
minimum,watchingforpossiblecolorshift.
9.Re-adjusttheCRTDrivecontrolsforbesthightolowlightgrayscale.
VideoProcessorPanelControls
1. Setallcustomercontrolstomidrange.
2. Inserta barpatternfrom anNTSCgenerator.
3.SetRP5(Peakcontrast)tofullCCW.
4. AdjustRP4(Subbrightness)untilthelastlineisblack.
5.AdjustRP2(Blacklevel)untilthefirstbariswhite.
6.AdjustRP3(Subpicture)fora sharp,uniformdivisionbetweenbars.
7.View a picturewithbrightwhitehighlights.Checkforbloominginthewhiteareasr
orrasteredge.ReadjustRP2and/orRP4untilbloomingdisappears.
NOTE: If a barpatterngeneratorisnotavailable,theadjustmentsmaybemadeonahighwhite
levelpicture.BeginwithRP2andRP4setfullyCCW.RP5shouldalwaysbesetfullyCCW.
SetRP3to75%rotationtowardsCCW.BeginrotatingRP2CWuntilminimumbloomingisthe
whiteareasisobserved.Iftheoverallpicturebrightnessisbelowproperviewinglevelbefore
thisoccurs,turnRP4CWslightlyandbeginprocedureagainwithRP2fullCCW.Repeatuntil
picturehasbrightwhites,properblacklevelandacceptablecontrastwithnobloomingorraster
bounce.
LuminancePeakingControl
TheLuminancePeakingadjustmentismadeusingtheinternalCrosshairpatternandthetuneron
alivechannel. RP1, PeakLuminancecontrol,islocatedontheVideoProcessorPanelnextto
theCombFilter.
1. SetthePicturecontroltomidrange.
2. SettheBrightnesscontroltomidrange.
3.SettheSharpnesscontroltofullCW.
4. Adjust RP1 untilminimumringingoccursattheleftedgeoftheverticalline.
NOTE: Thesetroubleshootingchartscannotbeallinclusive.Theyaremeanttobea service
guideonly.Thereareseveralsafetyand/orprotectioncircuitsinthesetwhich,if activated, can
resembleormasktheactualdefect.Onesuchcircuitistheverticalfailsafecircuitwhichcan
causea lossof video. Useoftheservicemanualwillbeneededtoresolvethistypeofproblem.

SymptomPage
DeadSet- Chart 1 18
NoAudio,NoVideo- Chart2 18
NoAudio- Chart3 18
NoAudio,NoVideo- Chart4 19
NoVerticalDeflection- Chart5 19
PictureRolls- Chart6 19
SetShutsDown- Chart7 20
TunerVoltages- Chart8 20
OneColorMissing- Chart9 20
ColorBandAtBottomOfPicture- Chart1021
SetDoesNotConverge- Chart1121
PincushionErrorTop/BottomAndSides- Chart1222
NOTE: Thesetroubleshootingchartscannotbeallinclusive.Theyaremeanttobea
serviceguideonly.Thereareseveralsafetyand/orprotectioncircuitsinthesetwhich,
ifactivated,canresembleormasktheactualdefect.Onesuchcircuitisthevertical
failsafecircuitwhichcancausea lossofvideo.Useoftheservicemanualwillbe
neededtoresolvethistypeofproblem.

r SupplyPanel DeflectionPanel
ThePowerSupplyPanel,Figure 3,isnottobe repaired or
In.theNON«
dGVlf6S>and Servlceadjustments
ntheNONSERVICEareasaresealedbymetalcovers.However
herearesomechecksintheTroubleshootingChartsthatshow
if the panelneedsreplacing.ChecktheSymptomIndex
RYt
POWER
RELAY T1
POWER
TRANSFORMER
NONSERVICEABLE
AREA
Figure3—PowerSupplyPanel
POWER SUPPIV PAKJP|
VOLTAGES
TEST POINTS
' 12VDC STAND-BY
J106-1
4
24VDC START-UP
TP2, J107-7
* 305VDC
TP6
130VDC
TP7. J108-6
6.8VDC
TP5
TheDeflectionPanel,Figure 4, uses one socketed ICinthe
verticalcircuit.IC3 isthe VerticalRampAmpwhichdrives hP
VerticalWaveformAmpIC4ontheConvergencePane?Should
replaced"eCeSSary °'her
C"CU,,S- ,he
DeflectionPanel is
NONSERVICEABLE
AREA
Figure 4— DeflectionPanel
DEFLECTION PANEL
VOLTAGES TESTPOINTS
24VDCSTART-UP J215-2.J217-11
130VDC
J210-1. TPL 1
16VDCDERIVED TP12.J208-2
-16VDCDEIIVED TP13.J208-!
J206-8
24VDCDERIVED TP14.J206-7
J204-1. J205-4
J215-3
13VDCDERIVED TP15.J206-1
J205-6.J207-5
J204-2. TP11
J203-3.J202-5
200VDCDERIVED TP16.J205-1
45VDCDERIVED
TP17
40VDCDERIVED J204-4
2LOVDCDERIVED J215-8
LOVDCDERIVED J108-3
IC3
RAMP AMP
RP3
V. LINEARITY
RP1
OVERVOLTAGE
SENSE