Sharp SD-AT1000W Especificaciones Pagina 244

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Section-5 Maintenance
October 17, 2013
564
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypower priortoservicing. 8882693004
STEP 7 Replacethefrontpanelandfingertightenthefasteners.Donotusea
screwdrivertotightenthethumbscrews.
STEP 8 Endofprocedure.
5.10.3 OperationWithInoperativeModules
ThePABPAmodulerejectloads,locatedinsidethePABmodulecombiner,aresizedwithenoughmargintoallow
operationunderanyimbalanceconditionthatmaybeencountered.AslongasonePABmoduleandonePSmodule
areinstalledandoperationalthepowerblockwillcontinuetoproduceRFpowerbu
tatreducedlevels(theoutput
leveldependsonhowmanyPABmodulesareremoved).
Removalofanac
tiveLPUPAmodulerequireswillcausethetransmittertostopproducingRFsincePABRFinputwill
belost.
5.10.4 PAModuleBias
RebiasofthePAmodulesisnotrequiredontheMaxivaUAXseriestransmitters.
5.10.5 PAModulePhasing
PhasingofthePAmodules(andthepalle tinsidethem)istightlyc on tr o lle datthefactory .NophasingofthePAmodules
isrequiredinthefield.PAmodulescanbeuse dinanylocationwi thout rephasing.
Note
Phasing between PABs is required to minimize PAB combiner reject power and it is accomplished via the
cables that go to the PAB combiners. The cables to the PAB combiners must be identical in length for
proper combining and maximum output power.
5.10.6 PSModuleRemovalandReplacement
STEP 1 LoosenthumbscrewonfrontofPSmoduleandcarefullypullthemoduleout
oftherack.
STEP 2 Inspecttheconnectorsontherearofthereplacementmoduletobesure
thereisnodamagetothePSconnectors.
STEP 3 InspectthePSconnectorsinsidetheracktoconfirmthereisnoblockageor
damageonrackconnectors.
STEP 4 SlidethePAmodulegentlyintotherack(handledown)untilcontactismade
withthematingconnectors.
STEP 5 Pushevenlyonthemodulehandle(usetheoutsideedgesofthehandleto
avoiddeformingthehandleinthecenter)withaslightsidetosidemotionto
helpalignthematingconnectors.
STEP 6 FingertightenthePSmodulethumbscrew.Donottightenthumbscrewwith
ascrewdriver.
STEP 7 Endofprocedure.
5.10.7 VerificationofFailedFET
EachPAmodulecontainsonePApalletboard.EachpalletcontainstwoFETs.InordertoidentifyafailedFETusethe
followingprocedure:
STEP 1
RemovethePAmodulefromthesystem.Allowittocoolifitishottothe
touch.
STEP 2 RemovethePAmodulecover.
STEP 3 Useavoltmeter(Fluke87forexample)tomeasuretheresistancebetween
theFETgatesandground.
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