Sea Tel 4012 User manual

Field Service Procedure – Replacement Pol Pot Kit, 4012
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136829 Rev A
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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polpotonthe4012antenna.
2. Checklist:
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VerifyRangeofMotion
VerifyPotFeedback
MeasureResistance
3. TheoryofOperation:
Apolangpotentiometerisusedtoprovideafeedbackreferenceforthepositionofthefeedassemblyforlinear
polarization.Thepotactsasapotentialdividergivinganoutputvoltagewhichvariesfrom0VDCto5VDCthroughoutthe
feedassembly’s270degreerangeofmotion.The4012antennahasaphasecardinstalledinthefeedhornwhichwill
reflectthesignalmeaningforeach0.5degreeofphysicalrotationofthefeedthechangeinsignalwillbe1.0degree
meaningthatthefeedassemblyofthe4012antennaonlyhastophysicallydrive135degreestoviewthefull270degrees
ofrotation.
TheICUconvertsthevoltageoutputfromthepotintothenumericalvaluetoalignthefeedintherequiredposition
basedonthevesselsGPSlocationandthelookangletotherequiredsatellite.Afailurewiththepotwillcauseittooutput
anincorrectvoltagewillresultinthefeedassemblynotbeingalignedcorrectlycausingbadcrosspolisolation.
Oneindicationthatthereisafaultwiththefeedalignmentofthesystemisthatthetargetlightwillbepermanently
illuminatedontheMXPandthattheantennawon’ttargetcorrectly.Itwillsit8degreesabove(or8degreesbelowat
highelevationlookangles)thesatelliteselevationlookangle.Aspartoftheantennastargetingprocedurethesystem
willtarget8degreesabove(or8degreesbelowathighelevationlookangles)thesatellite,calculatetheautothreshold
settingbasedonthenoisefloorlevelandthenalignthefeedforthecorrectreceptionpositionbasedonthevesselsGPS
locationandthelookuptable.Ifthesystemisunabletodrivethepolmotortoobtainthecorrectfeedback,orifthepot
hasfailedandwon’tgivethecorrectfeedback,theantennacan’tcompletethetargetprocessandtheantennawillstay
inthisposition.Settingthepolsettingtomanualwillmaketheantennatargetbyremovingtheautomaticfunctionfrom
thetargetingprocess;howeverthemissalignmentofthefeedwillcausebadcrosspolisolation.
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Field Service Procedure – Replacement Pol Pot Kit, 4012
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4. VerifythePolPotsCalibration:
Toverifyifthe4012antennaspolarityfunctioniscalibratedandoperatingcorrectlydrivethepoltoverifythatthefeedis
alignedcorrectly(thepolpotiscorrectlycalibrated)andalsothatthepotisoutputtingthecorrectresistances
throughoutitsrange.Thiswillalsoverifyifthepolmotorisdrivingcorrectly.
LogintotheMXPandfromtheconfigurationmenuselectthe“Reflector”pagefromtheconfigurationsectionandverify
thepolangdriveoptionissetto“Automatic”.
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Nowselectthe“PositionAntenna”screenfromthetoolswindowandconfigurethesatellitesettingsasfollows:
Longitude=EnterthelongitudinalvalueofyourcurrentGPSlocation.I.e.ifyourcurrentlocationis1degree
westofGMTenter“1.0W”intothelongitudeofthesatelliteparameters.
TXPolarity=HORZ
Nowpressthesubmitbutton(asshownbelow).
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Theantennawillnowtargetthedesiredpositionandalignthefeedaccordingly.Oncetheantennahasstopped
targeting,turnoffthetrackingfunctiontopreventitfromgoingintoasearch.
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Field Service Procedure – Replacement Pol Pot Kit, 4012
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Viewthefeedhornandverifythatthealignmentpinsofthephasecardarealignedvertically(onthetopandbottomof
thefeedhorn)youshouldalsonoticethetammountingscrewsareparallelwitheachotherasshownbelow…
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Anyerrorinalignmentisanindicationthatthepolpotisnotcorrectlycalibrated.Howeverasmallamountoferrorcould
becalibratedoutbyusingthelinearoffsetsetting(toelectronicallyadjustthepolpostion).
Ifit’sdeemedthereisalargeamountoferrorthencalibratingthepolpotwillberequiredasperFig.22toFig.27in
section8ofthisdocument.
Ifnodrivewasissuedthefunctionofthe24VDCpolangmotorshouldbeverifiedaspersection7ofthisdocument.
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5. VerifytheFeedAssembliesRangeofMotion:
Toverifyifthe4012antennaspolarityfunctioniscalibratedcorrectlyrefertosection3ofthisdocument.
Onceverifiedthatthepotiscalibratedthenextstepwillbetoverifythatthesystemhasthefullrangeofmotion(135
degreesofphysicalrotation),verifyingthatthepolpotisoutputtingthecorrectresistancethroughitsrangeandalso
thatthepolmotorisdrivingtheassemblycorrectly.
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1. Toverifytherangeofmotiononthefeedassemblyenterintothe“Reflector”screenundertheconfiguration
optionsandsetthepolangdrivemodetomanualandclickthesavebutton.
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Thiswillnowgiveyoutheabilitytomanuallydrivethepolasopposedtothefeedautomaticallyaligningitself
basedonthevesselsGPSlocationandthelookangletothedesiredsatellite.
2. Nowenterintothe“PositionAntenna”screenfromthetoolsmenuandenterthevalue“‐90.0”intothelinear
windowofthepolangtargetoptionandpresstheenterkeyonthekeyboard.
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Field Service Procedure – Replacement Pol Pot Kit, 4012
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consent of Sea Tel, Inc. 

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Thefeedhornshouldrotate45.0degreesclockwise(whenviewedfromthefrontofthereflector)sothatthe
alignmentmarksofthephasecardinthefeedhornarealignedvertically,fromlefttoright(asshownabove).
3. Nowenterintothevalue“00.0”intothelinearwindowofthepolangtargetoptionandpresstheenterkeyon
thekeyboard.
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Thefeedhornshouldrotate45.0degreescounter‐clockwise(whenviewedfromthefrontofthereflector)so
thatthealignmentmarksofthephasecardinthefeedhornarealigneddiagonallyinanorth/eastposition(as
shownabove).
4. Nowenterintothevalue“90.0”intothelinearwindowofthepolangtargetoptionandpresstheenterkeyon
thekeyboard.
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Thefeedhornshouldrotate45.0degreesclockwise(whenviewedfromthefrontofthereflector)sothatthe
alignmentmarksofthephasecardinthefeedhornarealignedhorizontally,fromtoptobottom(asshown
above).
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Field Service Procedure – Replacement Pol Pot Kit, 4012
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5. Nowenterintothevalue“180.0”intothelinearwindowofthepolangtargetoptionandpresstheenterkeyon
thekeyboard.
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


Thefeedhornshouldrotate90.0degreesclockwise(whenviewedfromthefrontofthereflector)sothatthe
alignmentmarksofthephasecardinthefeedhornarealigneddiagonally,inanorth/westposition(asshown
above).
6. Ifthesystemcompletesalloftheaboveteststhanthepolangassemblyisoperatingcorrectly.
Settheantennabackintoautomaticpolangmodebyenteringintothe“Reflector”screenunderthe
configurationoptionsandsetthepolangdrivemodeto“Automatic”andclickthesavebutton.
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TheantennawillnowautomaticallycalculatethecorrectreceptionpositionforthefeedbasedonthevesselsGPS
locationandthelookangletothedesiredsatellite.
Shouldthefeedassemblydrive,butnottargetthecorrectpositionthisisanindicationthatthepolpotisnotcalculating
thefeedbackcorrectlyanditsresistanceshouldbeverifiedaspersection6ofthisdocument.
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Field Service Procedure – Replacement Pol Pot Kit, 4012
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6. VerifytheResistanceofthePolPot:
Thepolangpotentiometer(polpot)consistsofaninternalslideraswellasaclockwiseandcounter‐clockwisecontact.To
verifytheresistanceofthepotamultimetercanbeusedtomeasurebetweenthesliderandoneofthewiperswhilst
rotatingtheshaftthroughitsrangeandverifyingthe0–5ohmsisoutputtedcorrectly.RemovethepotfromtheRFcage
asperthereplacementprocedureofthisdocumentandmeasuretheresistance.
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Lookingdownontotheshaftofthepotrotateitclockwiseuntilit
reachesitsendstop.
NowmeasuretheresistancebetweenthesliderandtheCCW
contact(greycable,pin2ontheIDCconnectorandtheredcable
pin3ontheIDCconnector).
Thefeedbackshouldbeapproximately5kohms.
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Nowslowlyrotatetheshaftofthepotcounterclockwise,the
readingshouldcountdownsequentially.Afteroneandahalfturns
thepotwillbeinthecenterofitsrangegivingaresistanceof
approximately2.5kohms.
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Continuetorotatethepotuntilthecounterclockwiseendstop(it
willnowhaveturnedthroughall3rotationsofitsrange),the
resistanceshouldbeapproximately0ohms.
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Leavingthepotatitscounterclockwiseendstopmeasurebetweentheclockwisecontactandtheslider(greycable,pin2
ontheIDCconnectorandthebrowncablepin1ontheIDCconnector)theresistanceshouldbereversedfromthe
previousrotation,reading5ohms.Rotatingtheshaftofthepotclockwiseshouldreducetheresistancethroughitsrange
to0ohms.Anyerrorwiththepotnotgivingthecorrectresistanceisanindicationthepotisdefectiveandneeds
replacing.

Field Service Procedure – Replacement Pol Pot Kit, 4012
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Tel, Inc. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 

7. MeasureMotorVoltage:
Leavingthepolangsettinginmanualmode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ICUmainPCBisn’toutputtingthevoltagetodrivethemotorandneeds
replacing.AslongasthepolrangeiswithinthepotlimitstheICUwillissuethevoltagetodrivethemotorbasedonthe
antennatargeting,achangeinthevesselsGPSpositionoroperatorinputs.Themotorwillthen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ICUmotherboardPCB.
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consent of Sea Tel, Inc. 

8. Replacingthe4012PolPotAssembly:
8.1. Tools.

2.5mmAllenWrench/Key
4mmAllenwrench/Key
Snips/Cutters
17mmWrench/Spanner
3mmAllenWrench/Key
2mmFlatBlade(Terminal)Screwdriver
Ruler/StraightEdge
CableTies/TieWraps
Loctite242

8.2. Procedure.
Procedureforreplacingthepolpot,SeaTelkitpartnumber:136741(polpotpartnumber:115425‐6).

*Caution:Powerdownthepedestalbeforefollowingthis
procedure.
1.Usinga2.5mmAllenwrenchremovethefourscrews
securingthefeedhorntothefrontofthereflectorand
removethefeedhorn.Savethehardwareforfuturesuse.


2.Disconnectthemilitaryspecconnectorfromitssocketto
allowaccesstothescrewstoremovetheupperbracket.


3.Removethe5screwswhichsecuringthemountingplate
withthecannonconnectionandIDCconnectionPCBtothe
RFcage.Retainthehardwareforfutureuse.
*Note:Themountingplatewillremainattachedtothe
harnesswhiletheRFcageisremovedfromtherearofthe
reflector.
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
4.SnipthecabletiesecuringtheRFcageharnesstothe
mountingplate


5.Disconnectthepolpot,polmotorandopticalswitchIDC
connectionsfromtheterminationblockonthe


6.DisconnecttheorangecoaxcablefromtheX‐PolLNB.



7.DisconnecttheyellowcoaxcablefromtheCo‐PolLNB,
mountedontheundersideoftheRFcage.


8.Snipthecabletiesecuringthereceivecoaxcablestothe
RFcage.
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

9.DisconnecttheDCpowerconnectionfromtheBUC(also
mountedontheundersideoftheRFcage).


10.DisconnecttheTXIFcoaxcablefromtheBUC.



11.UnwindtheharnessfromaroundtheRFcageandsetit
overthecrosslevelbeamtoallowremovaloftheRFcage
fromtherearofthereflector.


12.Usinga17mmwrenchremovethefourmountingnuts
andwasherssecuringtheRFcagefromthebackofthe
reflector.Savethehardwareforfutureuse.
13.SupporttheweightoftheRFcagewhileremovingitfrom
therearofthereflector.


14.Usinga3mmAllenwrenchremovethe4screwsfromthe
waveguideflangematedtotheCo‐PolLNB.Savethe
hardwareforfutureuse.

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consent of Sea Tel, Inc. 


15.Usinga4mmAllenwrenchremovethe5screwssecuring
thebrackettotheRFcage.Savethehardwareforfutureuse.
*Note:Thefour3mmscrewsdonotneedtoberemovedto
gainaccesstothepolpot.


16.RemovethebracketalongwiththeCo‐PolLNBasa
completeassemblytoallowaccesstothepolpotassembly.


17.Usinga3mmAllenwrenchloosedthepolmotorscrews
enoughtoallowthebacklashgeartobedisengagedfrom
themainsprocket.


18.Removethecablewraptofreethepolpotharnesssothe
assemblycanberemoved.
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consent of Sea Tel, Inc. 


19.Usea3mmAllenwrenchtoremovethe2screwsthat
mountthepolpotassemblytothebottomplateoftheRF
cage.Retainthehardwareforfutureuse.
20.Pullthefailedpotforewardandliftituptoremovethe
defectivepolpotassembly.
21.Installthereplacementpolpotassemblyinthesame
manner,applyingLoctite242tothethreads.Donotfully
tightenthescrewsatthistime.


22.FliptheRFcageovertoexposethefeed/motor/pot
gears.
23.Connectyourmulti‐meterandmeasuretheresistance
across,theredandgreywireconnectionsintheIDC
connectorUsingneedlepointprobes,orwiresinsertedinto
theIDCconnectorpins.
24.Setthemulti‐metertoOhms/Resistancefunction.


25.Thepicturetotherightistheviewlookingdownonthe
assembly.Youwillrotatethefeedthroatbyhandasneeded
toalignthe2alignmentpinholeswiththe2outerholesin
thelongaxisoftheRFCagemountingplate.Usearuler
(straightedge)toalignthepinswithcenterthreadedholes
onouteredgeofthelongaxisoftheRFCageMounting
Plate.


26.Whileholdingthefeedinalignment,carefullycoverthe
portwithtapetopreventitfromrotatingandtokeepany
debrisfromaccidentallyenteringthefeed.Verifythatthe
feedisstillproperlyaligned.
27.Rotatethebacklashgear(potshaft)toameasure
resistanceof3050+/‐50ohmsonthemulti‐meter.
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consent of Sea Tel, Inc. 

28.Useascrewdrivertoholdthebottomhalfofthebacklash
gear(potshaft)steadywhilerotatingthetophalfCWone
tooth(againstthespringaction)andpushthepotassmebly
forwardtomateintothedrivengearinthefeed.
29.Holdtensionagainstthepotbracket,andwhileassuring
thatthepotresistancereadingisstill3050+/‐50ohms,
tightenthemountingscrews.
30.Ifthepotresistanceisnot3050+/‐50ohms,repeatsteps
23‐29untiltheproperreadingisachievedatexactfeed
alignment.
31.Removethetapefromthefeedandverifyalignmentand
resistancewhenexactlyaligned.Ifcorrect,thiscompletes
calibrationoftheassembly. 

32.RoutethepotwiresthroughttheRFcagewheretheywill
notbepinchedwhenre‐installingthesidebracketandinstall
theharnessesbackintothewrapremovedisstep18.



33.FliptheRFcageovertoexposethepolmotorbacklash
gear.
34.Useasmallflatbladescrewdrivertoholdthebottomhalf
ofthebacklashgearsteadywhilerotatingthetophalfCW
onetooth(againstthespringaction)andpushthemotor
assemeblyforwardtomateintothedrivengearinthefeed.
35.Onceengagedtightenthescrewssecuringthepolmotor
tothebottomplateoftheRFcageusinga3mmAllen
wrench.ApplyLoctite242tothethreads.
*Note:Precisealignmentofthefeedisnotrequiredwhen
re‐couplingthemotor.


36.InstalltheCo‐PolLNBandbracketassemblytotheRF
cageusingathe5screwsremovedinstep15anda4mm
Allenwrench.ApplyLoctite242tothethreads,donotfullt
tightenatthistime.
*Note:Ensurethewaveguidebracketisinstalledonthe
outsideoftheflangesothe5mountingpointsalign
correctly.
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consent of Sea Tel, Inc. 


37.Installthefourscrewsremovedinstep14tosecurethe
waveguideflangetotheCo‐PolLNBensuringtheLNBis
correctlyaligned.Applyloctite242tothethreads.



38.LocatetheRFcageontotherearofthereflector.
*Note:WhenreinstallingtheRFcageensurethatitis
orientedcorrectlysothatthealignmentpinontheleftside
ofthereflectorwilllocateintotheholeonthebackoftheRF
cage.(InthisorientationtheX‐PolLNBwillbeontherightof
theRFcage).



39.Usingthehardwareremovedinstep12securetheRF
cagetotherearofthereflectorusinga17mmwrench.Apply
Loctite242tothethreads.


40.RoutetheharnessassemblybackovertheRFcageand
connectthefollowingconnections:
41.ConnecttheorangecoaxcabletotheX‐PolLNB(onthe
rightoftheBUC).
42.ConnecttheyellowcoaxcabletotheCo‐PolLNB
(underneaththeBUC).
43.Connecttheblack,TXIFcabletotheBUC.


44.SecurethecoaxcablestotheundersideoftheRFcage
usingcableties.
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consent of Sea Tel, Inc. 


45.RoutetheBUCDCpowercablearoundbetweenX‐Pol
LNBandtheRFcageandconnectittotheBUC.


46.SittheupperbracketontopoftheRFcageand
reconnecttheIDCconnectorswiththe4‐pinsensor
connectorontheleft,the5‐pinpotconnectorinthecenter
andthe2‐pinmotorconnectorontheright(asshowninthe
imageontheright).


47.Securethepot,motorandsensorharnesstothe
undersideoftheupperbracketusingacabletie.


48.Usingthehardwareremovedinstep3securetheupper
brackettotheRFcage,tighteningwitha4mmAllenwrench.
ApplyLoctite242tothethreads.


49.Reconnectthemilitaryspecconnectortoitsmounting
bracket.


Field Service Procedure – Replacement Pol Pot Kit, 4012
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Page16of16
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Document No
136829 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. 


50.Reinstallthefeedhornusingthehardwareremovedin
step1,tightenwitha2.5mmAllenwrench.ApplyLoctite242
tothethreads.
*Note:Thefeedhornhasalignmentpinslocatedinittosoit
canonlybeinstalledwiththephasecardinthecorrect
orientation.Verifytheseareinthecorrectpositionwhen
installing. 

51.Accesstheconfiguration–reflectorpagetoadjustthe
linearoffsetvaluebytheamountofchangeinskew.
*Example:Theamountofchangeinskewwas+2degrees,
soyouneedtoaddthatamounttowhatevervalueis
currentlyinthelinearoffsetfield.Ifthechangeinskewisa
negativevalue,youwillsubtractfromthevalueinthelinear
offsetfield.

Savethefinallinearoffsetvalue.
LogoutoftheMXP.

