Sea Tel ST88 User manual

Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
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
Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


1. BriefSummary:
TroubleshootingdocumentfordiagnosingafaultwithandreplacingthePCUassemblyontheST88,ST94andST144
antennas.
2. Checklist:

VerifyInitialization
MeasurethePowerSupplyInput/OutputVoltages
PCUStatus
PedestalError
VerifyStabilization
VerifyTargeting
TestforAzimuthDrift
VerifytheCommunicationsPath
TestPolDrive
3. TheoryofOperation:
TheMK2PCUassemblycontainsthe24VDCpedestalpowersupply(kit:135341),PCUmotherboardPCB(kit:135338),
motionplatformPCB(kit:135342)andabovedecks400MHzmodemPCB(kit:135349).
ThePCUmotherboardcalculatestheamountofmovementfromthevesselbasedonthefeedbackfromthesensorson
themotionplatformPCBanddirectionalchangesfromthevesselsgyrocompasswhicharefedintothecontrolloop.It
thensendsthecommandtotheMDEenclosuretodrivetherelevantaxisbyanequalandoppositeamountofmovement
tomaintainstabilizationandcontroltheantennasdishscanpattern.ThePCUsoftwareconfiguresthefunctionofthe
pedestalandiscalibratedbytheN0parameterwhichsetsthemotorgainsforthesizeoftheantennaaswellas
configuringthedishscanpattern.TheMK2XX09PCUMotherboardPCBfeaturesanintegratedPolAuxrelayPCBaswell
asstatusLEDsfordiagnosticpurposes;aMiniUSBportforsoftwareuploadsandserviceserialportforBluetooth
connection.
ThemotionplatformPCBhouses5sensors.TwosolidstateMEMsensorswhichareusedastheantennashorizon
reference(levelposition)andlongtermstabilizationreference,and3solidstateratesensors,oneforeachaxis,whichare
usedforshorttermstabilizationreference.AfaultysensoronthemotionplatformPCBwillcausetheantennatolose
stabilityandmispointfromthesatelliteunderdynamicconditions;howeverthesystemmayappeartobeoperationalin
theportwhenthereisnomotiontocounteract.
RS‐422PedestalcommunicationsfromtheDAC‐2202aremodulatedintoafrequencybythebase400MHzmodemand
diplexedwiththeL‐Bandreceivesignal.Thecommunicationsfrequencywillthenbedemodulatedbythepedestal
400MHzmodemandconvertedbackintoRS‐422beforebeingsenttothePCU.RadioMandCsignals(RS‐232,RS‐422,or
RS‐485)canalsobemultiplexedalongwiththepedestalcommunicationstointerfacewiththeSSPB.

The150W,24VDCpowersupplyisswitchmodeandwillconverteither110VACor220VACinto24VDC.Thiscomponent
isuniversallyusedintheDAC‐2202,XX97andXX06pedestalpowersuppliesaswellastheXX09andXX10PCU’sand
NJRC24VBUCpowersupplies,meaningonlyasingleunitisneededasasparetocoverawiderangeofapplications.


Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
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
Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


4. VerifyInitialization:

Powercyclethepedestal
1. BrakesreleasefromtheELandCLmotors
2. Elevationaxisdrivesto45degreesbasedonthemotionplatformPCBshorizonreference
3. CrosslevelaxisdrivestolevelbasedonthemotionplatformPCBshorizonreference
4. Azimuthaxisdrivesclockwiseuntilthehomeflagandsensormakecontact

*Note:IfthePCUsoftwareis2.01aorhigher,theELandCLaxiswillinitializeatthesametimesaving20secondsonthe
initializationprocess.

IftheACUreportsmodel"xx09",thePCU’sN0parameterneedscalibrating,refertothe“calibratingthePCUSystem
Parameter(N0)”sectionofthisdocument.Failureofanyoftheinitializationsteps,orapedestalerrorrequiresfurther
troubleshooting.
5. PowerSupplyTroubleshooting:


*Caution:ElectricalHazard‐DangerousACvoltagesexistonthe
powersupply.Observepropersafetyprecautionswhenworking
onthepowersupply.
1.RemovethecoverfromthePCUtoallowaccesstothepower
supplyfortesting.
2.Measuretheinputvoltageintothepowersupplyonthe2pins
totherightoftheconnectionblock,110‐240voltsACshouldbe
present.IfnoACvoltageispresentverifytheunitisswitchedon.
Ifthereisstillnovoltagepresenttroubleshootthesource.


3.Nowmeasuretheoutputvoltagefromthepowersupplyonthe
2pinstotheleftoftheconnectionblock,theoutputshouldbe
24VDC.
*Note:ThisprocedureshowsaDAC‐2202intheimages;however
theDACandPCUpowersupplyisthesamecomponentsothe
procedureisthesame.


IftheunitsACinputhasbeenverifiedandthe24VDCisnotpresent,thepowersupplyisdefective.Ifthepowersupplyis
outputtingthe24VDCconsistentlythenthepowersupplyisoperationalandtheproblemlieselsewhere(possiblefailure
withthePCU,DACmotherboardorharnessconnection). 

Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
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Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


6. PCUStatusLEDDiagnostics

AstatusLEDisinstalledonthePCUMotherboardandcanbeviewedfromtheundersideofthePCUassembly.The
differentcolorsstatusesindicate...

SolidGreen

PCUstatusisgood.


SolidRed

PCUfaultdetection.OperationalsoftwarewillneverleavethestatusLEDsolidRED.

ReprogramthePCUsoftware.ReplacethemotherboardPCB.

SolidOrange

SoftwareupdatetothePCU

motherboardisinprocess.


BlinkingOrange

Softwareupdatetothemotordriverenclosure(throughthePCU)isinprocess.


BlinkingRed

Communicationerrorwiththemotordriverenclosure.ChecktheMDEstatusLEDs.IfMDEis

good,checktoassurethattheharnessconnectionsareseatedproperly.Checkharness
connections(pin‐pin,wire‐wireandwire‐ground)forgoodcontinuity.ReplacemainPCB.
ReplaceMDE.

7. PedestalError(Error8):
7.1. DecodingaPedestalError(Error8).
WhentheDACdisplaysapedestalerrorenterintotheremotecommandwindowandinput“S0000”thenpress
entertwice.TheerrorcodewillnowbedisplayedintheRemoteMonitorscreen.Decodethe4thcharacterofthe
errorcodefromthebelowtable...



@NoneKRef+LV+CLVStabLimit+AZ+LV
ACLLRef+AZWStabLimit+AZ+LV+CL
BLVMRef+AZ+CLXStabLimit+Ref
CCL+LVNRef+AZ+LVYStabLimit+Ref+CL
DAZORef+AZ+LV+CLZStabLimit+Ref+LV
EAZ+CLPStabLimit [StabLimit+Ref+LV+CL
FAZ+LVQStabLimit+CL\StabLimit+Ref+AZ
GAZ+LV+CLRStabLimit+LV]StabLimit+Ref+AZ+CL
HRefSStabLimit+CL+LV^StabLimit+Ref+AZ+LV
IRef+CLTStabLimit+AZ_StabLimit+Ref+AZ+LV+CL
JRef+LVUStabLimit+AZ+CL

Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
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
Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


7.2. ErrorTypes.
The3typesofpedestalerrorare.....
1. ServoLimit(CL,LVandAZ)–AservolimiterrormeansthePCUmotherboardisissuingthecommandtothe
motordriverenclosuretodrivetherelevantaxisharderthanitshouldundernormaloperation(theservolimithas
beenreached).Thiscouldbewhilsttheantennaistryingtomaintainitspointingangle,orwhilsttheantennais
drivingtheaxistoatargetposition.
2. StabilityLimit–Astabilitylimiterrormeanstheantennahasmispointedfromitsdesiredtargetpositionbymore
thanhalfadegree.WhenastabilitylimiterrorisflaggedonaVSATantennatheDACwillsendtheTXMute
commandtoinhibitthetransmitfunctionofthesatellitemodem(It’scommontoseetheservolimitandstability
limiterrorstogether).
3. AZReferenceError–Anazimuthreferenceerrormeansthereisacorruptreadingintheantennasrelativescale.
Thiscouldbecausedbythesystemcompletinga360degreerotationwithoutthesensorcomingintocontactwith
thehomeflag,thesensorcomingintocontactwiththehomeflagtooearly,oraphysicalproblemsuchasthechain
orbeltslippingonthemotorpulleyorthepulleyslippingonthemotorshaft.
7.3. TroubleshootingPedestalErrors–ServoLimitandStabilityLimit.
1. Reinitializethepedestal.Doesitdrivecorrectlyornotatall?‐IfnoneoftheaxisdriveverifytheN0andmotorgain
parameters(N1=CL,N2=ELandN3=AZ)arecorrectlyconfiguredinthePCUthroughtheRemoteCommand
windowoftheDAC.
2. Verifythebalanceoftheantennaandcheckforphysicalrestrictionsonthepedestal.Iftheaxisisn’tcorrectly
balancedthePCUwillbeoutputtingadditionaldrivecommandstomaintaintheantennaslevelposition.
3. Ifthemotorisn’tdrivingcorrectlyornomotordriveispresent,testthemotorforfaultsusingtheprocedurein
section8ofthisdocument.Ifyoufindthemotorisdefectivereplaceitandthentestthefunctionofthemotor
driver.Iftheaxisstillfailstodrivecorrectlythemotormayhavedamagedit.Replacethemotordriver.
4. Verifyifthebrakeshavereleasedproperly.Ifthemovementoftheaxisisrestrictedmeasuretheoutputtothe
motortoverifyifthe12VDCispresent.Ifsothebrakehasn’treleasedthemotorisdefective.Ifthe12VDCisn’t
presenttroubleshoottheharness/motordriverenclosure.
5. Anotherpotentialproblemcouldbeadamagedorintermittentharnessconnection.Removetheharnessback
shellsandverifyallthepinsareseatedcorrectly,checkcontinuityfrompintopinandalsoacrossthepinstoverify
thereisnoshortintheconnections.
7.4. TroubleshootingPedestalErrors–AzimuthReferenceError.
1. Reinitializethesystemandverifythesensorcomesintocontactwiththehomeflagasthesystemdrivesclockwise
inazimuth(theLEDwillilluminate).Ifnotverifyifthehomeflag/sensorispresent,ifcorrectthenit’sa
sensor/feedbackfailure.
2. Drivetheazimuthaxisin90degreeincrementsandverifythattheantennapointscorrectlyandthattheDAC
displaysthecorrectrelativeposition.Alsoverifythatthereisnophysicalrestrictionontheazimuthaxissuchasthe
chainorbeltslippingonthemotorpulleyorthepulleyslippingonthemotorshaft.


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8. TestTheMotor:
Checkcontinuitybetweenground(themotorconnectorbackshell)andthe3driveroutputsonpins1,2and3of
theharness.
Nowcheckcontinuitybetweenpins4,5,6,7,8andtheground(themotorconnectorbackshell).Orthismightbe
stepsinaprocedurethatdoesnotrequireatable.
Alsocheckbetweentheindividualpins1,2,3andtherestofthepins(i.e.testpin1topin4,5,6,7,8andsoon,
notbetweenpins1and2,1and3or2and3).
Ifthereisanycontinuitymeasuredonthestepsmentionedabove,themotorisdefective(whichwouldbe
highlightedbythediagnosticLEDsontheMDE).Theantennasoperationshouldbeverifiedwithareplacement
motor.Ifnormaloperationdoesn’treturntheMDE/PCUwillrequirefurthertroubleshooting.

9. VerifyStabilization:
Thepurposeofthisprocedureistophysicallymovethesystemsaxisunderstaticconditions,introducingerrorintothe
PCU’scontrolloop,andthenverifythesystemisabletoreturntoitslevelposition(stabilizeitself).Thesetestscanbe
performedbymonitoringthesensoroutputsonDacRemPoralsobyphysicallymovingtheantennaandobservinghowit
responds.

1. TurntrackingoffandopentheDISP_VscreenofDacRemP.ThesoftwarewillnowplotthelevelpositionoftheLV
andCLMEMsensors.Observeforanyabnormalities.
2. VerifyCrossLevelresponse:
Standingbehindthesystem,pushthecrosslevelbeamdowntotheleftandholditinposition.VerifythattheCL
traceonDacRemPmovesdownanequalamounttothemovementexertedontheaxis.Releasetheaxisandverify
theDacRemPtraceandsystemaxisbothreturnbacktotheiroriginalpositionsinstantly,withoutdeviatingor
takingtimetosettle.Nowpushthecrosslevelbeamdowntotherightandholditinposition.VerifythattheCL
traceonDacRemPmovesupanequalamounttothemovementexertedontheaxis.Releasetheaxisandverifythe
DacRemPtraceandsystemaxisbothreturnbacktotheiroriginalpositionsinstantly,withoutdeviatingortaking
timetosettle.
3. VerifyLevel(Elevation)response:
Pushthereflectorupinelevationandholditinposition.VerifythattheLVtraceonDacRemPmovesdownanequal
amounttothemovementexertedontheaxis.ReleasetheaxisandverifytheDacRemPtraceandsystemaxisboth
returnbacktotheiroriginalpositionsinstantly,withoutdeviatingortakingtimetosettle.Pushthereflectordown
inelevationandholditinposition.VerifythattheLVtraceonDacRemPmovesupanequalamounttothe
movementexertedontheaxis.ReleasetheaxisandverifytheDacRemPtraceandsystemaxisbothreturnbackto
theiroriginalpositionsinstantly,withoutdeviatingortakingtimetosettle.
4. InDacRemP,thetraceshouldlooksimilartothebelowimage.Notehowaftereachmovementthesystemreturns
toitslevelpositionefficientlywithouttakingtimetosettle.
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10. RateSensorMonitoring:
RatesensoroutputscanalsobemonitoredusingtheDISP_WscreenofDacRemPtoverifyanydeviationsunderstatic
conditions.Thetracesshouldremainconsistent;anydriftingorspikesareanindicationthesensorsvoltageoutputis
changingandthesensorisdefective(providednoforcesarebeingexertedonthesystem).


11. AzimuthTargeting:
Shouldtheantennahaveissuestargetinginazimuth,suchasnotaccuratelyfindingthesatelliteorrepeatedlyfindingthe
satelliteindifferentazimuthpositions,thenit’simportanttodiagnoseifthesystemismispointinginazimuthorrelative.
RelativefeedbackfromtheAZencodercanbeverifiedbyinitializingthesystem,verifyingitcalibratesitselfcorrectly,
andthendrivingthepedestalclockwisein90degreeincrementsovera360degreerotation.Notethatthesystempoints
correctlyrelativetothevesselandthatnoAZreferenceerrorisflaggedbythePCU.Amechanicalproblemsuchasthe
beltslippingonthesprocketcouldalsocausethiskindoferror.
Ifthesystemkeepsfindingthesatelliteatdifferentazimuthpositionsbutatthesamerelative,thentheencoderis
functioningcorrectlyandtheazimuthratesensoriscalculatingthemovementincorrectlycausingtheantennato
mispoint. 

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12. Drift:
Ifaratesensoris“drifting”,itsnominalvoltageoutputhaschangedfromthecorrect2.5VDC.Thiswillcauseerrorinthe
axiscontrolloopandcausetheantennatomove.ItismorecommontoseethisdriftintheazimuthaxisastheCLandEL
axisbothhavealongtermreference,providedbythetiltsensor.However,shouldtheratesensorsdriftbelargeenough,
itcanover‐compensatethetiltsensorandthesystemwilldriveintooneoftheCLorELendstops.
Toverifyifthesystemisdriftinginazimuth,turntrackingoffandmonitortherelativeposition.Understaticconditions,
whenthevesselsheadingisunchanged,therelativecountshouldremainstationary.Iftherelativevaluebeginsto
changefromitscurrentposition,theazimuthratesensorisdrifting,introducingerrorintotheaxiscontrolloop.
IftheratesensorsarecheckedasOK,ashipsgyrocaninducedrift.ThiswillintroducelooperrorintothePCUcontrol
loopandcausetheantennatodrift.ThiscanbeverifiedbycheckingtheheadingdisplayedontheDACagainsttheships
actualheading.Thetwoheadingsshouldbethesame.Ifthereisadifference,enableSatRefModetotemporarilybypass
theshipsgyrotoprovethefault.IfenablingSatRefModedoespreventdrift,verifytheheadingsource.
13. FurtherDiagnostics:
Ifanyoftheabovecheckshaveindicatedaproblem,oneormoreoftheaxiscontrolloopshaveincorrectlooperrors.The
mostlikelycauseofthisisadefectiveratesensor.Torectifythis,replacethemotionplatformPCBandrepeatthechecks
above,toverifytheantennanowfunctionscorrectly.
Shouldtheproblempersist,thereareotherpossibilitiesthatcanproducethesameresults.Thesecanbebad
connectionsbetweenthemotionplatformPCBandPCUmotherboardorthePCUitself.
14. 400MHzModemLEDIndicators:
Fordiagnosticpurposes,the400MHzFSKModemAssemblieshaveanLEDIndicator(locatedonthebottomlefthand
sideoftheEnclosureforBDEmodemsanddirectlyunderneaththeRotaryJointportonthe09SeriesPCU).Byobserving
theamountofambercoloredflashesduringpowerup,themodemsconfigurationmaybeestablished.Youcanalso
verifythecommunicationslinkbetweenabovedecksandbelowdecksmodemsthemselves.Refertothebelowlistfor
anexplanationofthedifferentLEDstates.

Uponpowerup,themodems’LEDwillflashamber.Thenumberofflashesindicatesthedashnumberconfiguration
ofthemodem.Refertotheconfigurationonpage8ofthisdocumentfortheappropriatedashnumber
configurationforyourmodemassembly.
Solidgreenindicatesdualchannelcommunicationslockbetweenmodems(i.e.thereisenoughsignalbeing
receivedtoestablishcommunications).
RedandGreenalternatingLEDsindicatesasinglechannelfailure(i.e.thereislowRSSIsignalstrengthonone
channel).
AflashingRedLEDindicatesnocommunicationbetweenbothmodems(2failedchannels),(i.e.thereislowRSSI
signalstrengthonbothchannels).
SolidRED‐Modemfaultdetection,hardwareorsoftwarefailureofthemodem.
SolidORANGE‐SoftwareupdatetotheModeminprogress.
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BelowDecksModemAssembly

AboveDecksModem(LocatedinthePCUAssembly)


LEDIlluminatedGreen


LEDIlluminatedRed

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15. 400MHzModemQueries:
The400MHzmodemassembliesfacilitatetheuseofline‐basedcommandsviatheACU’sfrontpanel,theinternalHTML
page,orusingremotediagnosticsoftwaresuchasDacRemPandProgTerm.Theuseofthesecommandswillaidin
troubleshootingcommunicationfailuresbetweentheabovedecksandbelowdecksmodems.Listedbelowarethe
availablecommands:




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16. ModemQueryMethods:
Thefollowingtextprovidesinstructiononhowtosubmitmodemqueriesusinganyoneoffourdifferentmethodsas
listedbelow.TheseinstructionsassumethattheoperatorhaveaclearunderstandingofMenunavigationandentryvia
theAntennaControlUnitfrontpanel,orconnectionrequirementsforusingremotediagnosticsoftware,and/orthe
internalHTMLpageoftheACU.Refertotheappropriatemanualtextiffurtherinstructiononwiringconnectionsor
buttonpushingisrequired.
16.1. UsingtheACUFrontPanel:

1. UsingtheACU’sfrontpanel,navigatethrough
thesetupmenutoaccesstheremote
commandsub‐menu.

2. Enterinthedesiredmodemquerythenpress
theenterkey.

3. Observeand/orrecordthedisplayedresponse.


16.2. UsingtheInternalHTMLPage:

1. LogontotheACU’sinternalHTML
page.
2. Browsetothe“communicationport
settings”page.

3. Inthecommandwindow,typeinthe
desiredmodemqueryandhitsend.

4. Observeand/orrecordthedisplayed
response.
5. Repeatasrequireduntilalldesired
modemqueriesarenoted.



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

16.3. UsingDacRemP:

6. OpenupDacRemPandselectthecomm
diagnosticsTool(cntrl+c).

7. IntheRemoteCommandEntryWindow,typein
thedesiredmodemqueryandhitenter.I.e“<1234
<CR>”

8. Observeand/orrecordthedisplayedresponse.
9. Repeatasrequireduntilalldesiredmodemqueries
arenoted.

16.4. UsingProgTerm:

10. OpenupProgTermandselectthetoolsmenu.

11. Select“modemtools”.

12. Selectthedesiredmodemlocation.
BDEistheBelowDecksModem.
ADEistheAboveDecksModem.

13. Selectthedesiredmodemquery.

14. Observeand/orrecordthedisplayedresponse.
15. Repeatasdesireduntilalldesiredmodemqueries
arenoted.


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
17. 400MHzModemFaultDiagnosticProcedure:
17.1. QuerytheADEandBDEmodems:
1. Issue“<0000”and“>0000”queriestotheADEandBDEmodemsandrecordtheresponses.

ADE(>0000)______________BDE(<0000)______________
2. Compareyourrecordedresponsestothelistbelowtodeterminewhichmodemfault(s)(ifany)arepresent.
3. Usetheappropriatetextfollowingthefailuretableforalistofpossiblefailuresattributedtothefailuretype
established.


17.2. ToolsSuggested:

LaptoporPCw/anavailablecomportand
diagnosticsoftwareinstalled
ProgTermVer.1.35orLater
DacRemPVer.0.20orLater
9pinSerialcable

Straightthru(1‐1Pinout)ForSerialBasedConnections
CAT5Cross‐overcable RequiredforIPbasedconnections(HTML,DacRemPIP)
SerialLoopbackConnector
BuildaLoopBackTestAdapterbyShorting
Pin1toPin8andShortingPin2toPin3on
afemaleDB9(S)connector.

SMA“T”splitterorNtype“T”splitter Orequivalentcabling
SpectrumAnalyzer Capableofhandling100KHzupto3GHzandupto48VDC


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
18. FailureTable:
Diagnosticsfromtheabovetable,section:17.1.
18.1. None.
NocommunicationfailuresbetweenADEandBDEmodems.
18.2. ReceiveIFPath.
ThefollowingpointsoffailuresassumesLEDilluminationonbothmodems.
1. ModemConfiguration.
VerifyBDEmodemandADEmodemareproperlyconfigured(jumperblocksettings).
2. CoaxCablefailure
Verifycontinuityonthebelowcoaxes,repairorreplaceasrequired.
1. BDEModemconnectorbracket(BaseRackPanelAssembly)
2. (CFE)BDEtoADERxIF(BaseRackPaneltoradomeConnectorBracket)
3. RxNtoSMAAdapter(Locatedonconnectorbracketatradomebase)
4. SMAtoSMA(Fromconnectorbrackettobottomthebottomsideoftherotaryjoint)
5. SMAtoSMA(FromtopsiderotaryjointtoPCU/ADEModem
3. RotaryJoint(Receivechannel).
Verifycontinuityonthereceivechannelforitsentire360degreerangeofmotion.Replacerotaryjointif
anysectorofithasfailed.
18.3. BDE/ADENoResponse.
TheFollowingpointsoffailuresassumesLEDilluminationonbothmodems.
1. ModemConfiguration
VerifyBDEmodemandADEmodemareproperlyconfigured(jumperblocksettings).
2. ACUtoBDEmodeminterfacecablefailure
Verifyharnesscontinuity.Repairorreplaceasrequired
3. ACUAntennaPortFailure
InstallanRS232Loopbackconnector**onAntennaPortoftheACU.Enteran“n0999”Remote
Commandandverifythatitechoesbackonthebottomlineofthedisplay.
1. Ifloopbackworks,BDEModemfailureorACUtoBDEInterfacecablefailure.
2. Ifloopbackdoesnotwork,ACUfailure.


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
18.4. ADENoResponse1(assumesLEDilluminationonbothmodems).
1. ModemConfiguration
VerifyBDEmodemandADEmodemareproperlyconfigured(jumperblocksettings).
InstallSpectrumAnalyzerinlinewiththeRxIFcoaxpath.
1. If465.0MHzTransmitBeaconispresent,thefaultistheBDEmodem.
2. If465.0MHzTransmitBeaconisNOTpresentfaultiswiththeADEmodem.
18.5. ADENoResponse2.
1. ADEModemConfiguration
VerifytheADEmodemisproperlyconfigured(jumperblocksettings).
2. CoaxCablefailure
Verifycontinuityontheitemslistedbelow,repairorreplaceasrequired.
1. BaseModemtoconnectorbracket(BaseRackPanelAssembly)
2. (CFE)BDEtoADERx(LMR‐400)
3. RxNtoSMAAdapter(Connectorbracketatradomebase)
4. SMAtoSMAconnectorbrackettobottomsiderotaryjoint
5. SMAtoSMAtopsiderotaryjointtoPCU/ADEModem
3. RotaryJoint(Receivechannel)
Verifycontinuityonthereceivechannelforitsentire360degreerangeofmotion.Replacerotaryjoint
ifanysectorofithasfailed.
18.6. BDEReceiveOrADETransmit(PEDMandC).
1. BDEModemRxPortFailure(Notreceivingat465.0MHz)or
2. ADEModemTxPortFailure(Nottransmittingat465.0MHz)
InstallSpectrumAnalyzerinlinewiththeRxIFcoaxpath.
1. If465.0MHzTransmitBeaconispresent,thefaultistheBDEmodem.
2. If465.0MHzTransmitBeaconisNOTpresentfaultiswiththeADEmodem.
18.7. BDETransmitOrADEReceive(PEDMandC).
1. BDEModemTxPortFailure(Nottransmittingat452.5MHz)or
2. ADEModemRxPortFailure(Notreceivingat452.50MHz)
InstallSpectrumAnalyzerinlinewiththeRxIFcoaxpath.
1. If452.5MHzTransmitBeaconispresent,thefaultistheBDEmodem.
2. If452.5MHzTransmitBeaconisNOTpresent,thefaultiswiththeADEmodem.


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18.8. BDEReceiveorADETransmit(RFMandC).
1. BDEModemRxPortFailure(Notreceivingat460.0MHz)or
2. ADEModemTxPortFailure(Nottransmittingat460.0MHz)
InstallSpectrumAnalyzerinlinewiththeRxIFcoaxpath.
1. If465.0MHzTransmitBeaconinpresent,thefaultistheBDEmodem.
2. If465.0MHzTransmitBeaconisNOTpresent,thefaultiswiththeADEmodem.
18.9. BDETransmitOrADEReceive(RadioMandC).
1. BDEModemTxPortFailure(Nottransmittingat447.5MHz)or
2. ADEModemRxPortFailure(Notreceivingat447.5MHz)
InstallSpectrumAnalyzerinlinewiththeRxIFcoaxpath.
1. If465.0MHzTransmitBeaconinpresent,thefaultistheBDEmodem.
2. If465.0MHzTransmitBeaconisNOTpresent,thefaultiswiththeADEmodem.


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19. 400MHzModemPCBConfiguration:
The400MHzmodemPCBhasajumperblock(locatedcomponentsideofPCB)thatisusedtoconfigureitforabove
decksorbelowdecksoperationaswellastoconfiguretheserialcommunicationsprotocol(RS232,RS422,orRS485).So
asinglePCBcanbeconfiguredtoworkineithertheaboveorbelowdecksbasedonthejumpersetting(s)ofthebelow
table.
Verifytheconfigurationofthedefectivemodeminstalledonyourantennaforthecorrectconfiguration.Standard
configurationsfortheXX09,XX10,XX11and9797BVSATsystemsuseRS232protocolsoareconfiguredto‐1inthe
abovedecksand‐2inthebelowdecks.
TheST88,ST94andST144TVROantennaswithMK2electronicsuseRS422protocol(asopposedtotheRS232protocol
usedontheXX09,XX10,XX11and9797BseriesVSATantennas)thereforethePCBisconfiguredtoa‐3asperthebelow
table.Shouldtheabovedecks400MHzmodemPCBneedreplacingononeoftheSTseriesantennaanadditionaljumper
isprovidedinthekittoplacebetweenpins3‐4onthePCBjumperblocktocorrectlyconfigurethecommunication
protocolofthePCB.







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20. PolDrive–ST88,ST94andST144:

AsthepolauxrelayisintegratedintotheMK2PCUmotherboardafaultwiththepolalignmentcouldpotentiallybe
causedbythisPCB.Ifnopoldriveispresentsetthepoltypetomanualmode(0009),applydrivetothefeedassembly
andmeasurethevoltagetothemotorontheIDCconnector,24VDCshouldbepresent.Ifvoltageispresentbutthe
motorisn’tdrivingthemotorisdefectiveandneedsreplacing.
Ifnovoltageispresentverifytheconnectionsofthereflectorharnessbymeasuringpintopinasperthebelowdiagram.



Iftheharnessconnectionsaregood,thenthePCUmotherboardisn’toutputtingthevoltagetodrivethemotorand
needsreplacing.
AslongasthepolrangeiswithinthepotlimitstheDACwillissuethepoldrivecommandtothePCUmotherboard,based
ontheantennatargeting,achangeinthevesselsGPSpositionoroperatorinputs.ThePCUmotherboardwillthendrive
thepolmotor,whichwilldrivethefeeduntilthecorrectoutputfromthepothasbeenreceived.Atwhichpointthefeed
willbeinthecorrectreceptionposition(providingthesystemisfunctioningandcalibratedcorrectly).Thereforethereis
alsothepossibilityforapoldrivefaulttobecausedbythePCUmotherboard. 

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

21. ReplacingtheMK2PCUAssembly:
21.1. Tools.

#1PhillipsScrewdriver
7/16”Wrench/Spanner
5/16”Wrench/Spanner
Snips/Cutters
2mmFlatBlade(Terminal)Screwdriver
CableTies/TieWraps
Loctite242

21.2. Procedure.
ProcedureforreplacingthePCUassembly,SeaTelkitpartnumber:137737(PCUpartnumberpartnumber:131057‐3).

*Caution:Powerdownthepedestalbeforefollowingthis
procedure.
1.Usinga#1Phillipsscrewdriverremovethescrew
securingthecoaxswitchconnectionofthereflector
harnessfromtheterminationblock.
2.RemovethecoaxswitchIDCconnectorfromthe
terminationblock.


3.Usinga7/16”wrenchremovethetwoRG‐179coaxcables
fromthelowermountingbracketinstalledontopofthe
PCU,notingtheirorientation.


4.NowdisconnectthetwoRG‐60coaxcablesfromthe
othersideofthemountingbracketusinga7/16”wrench.


Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
Page18of22
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Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


5.NowdisconnectthetwoRG‐179coaxcablesfromthein
outputsideofthecoaxswitchesusinga7/16”wrench.


6.NowdisconnectthefourRG‐60coaxcablesfromthe
inputsideofthecoaxswitchesusinga7/16”wrench,noting
theirorientation.


7.Usinga5/16”wrenchdisconnectthetwoSMAcables
fromthe400MHzmodemPCB.


8.DisconnecttheGPSantennasRJ‐45connectorfromthe
PCU.


9.UsingapairofsnipscutthecabletiesecuringtheRG‐179
coaxfromthecoaxswitchtothe400MHzmodem(inside
thePCU).


Field Service Procedure – Replacement PCU Kit, ST88, ST94 & ST144
Page19of22

Document No
137738 Rev A
Copyright © Sea Tel, Inc 2012 - The information contained in this document is proprietary to Sea
Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 


10.UsingapairofcutterssnipthecablesecuringtheAC
powerconnectortothePCUanddisconnecttheconnector.



11.Usinga2mmflatbladescrewdriverundothescrews
securingthereflectorandmotordriverD‐subconnectors
tothePCUanddisconnectthem.


12.CheckallcablingfromthePCUassemblyandcoax
switchhasbeendisconnectedfromthepedestaland
removethePCUandcoaxswitchassemblyusinga3/16”
Allenwrench.Savethehardwareforfutureuse.
*Note:Securetheweightoftheassemblywhileremoving
themountinghardware.


13.WiththedefectivePCUremovedfromthepedestaluse
a#1Phillipsscrewdrivertoremovethecoaxswitch
mountingplatefromit.Savethehardwareforfutureuse.


14.Usingthehardwareremovedinstep13installthecoax
switchonthereplacementPCUassembly,notingits
orientation.ApplyLoctite242tothethreads.
