580EXII Posibile Probleme

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  • 7/22/2019 580EXII Posibile Probleme

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    PreliminaryResearchReportonCanon580EXIIFlashFailuresByJimClark&TimAmbrose,ResearchandDevelopment

    LPADesignBackground:SincethelaunchofitsPocketWizardMiniTT1andFlexTT5modelsinearly2009,LPADesign(A.K.A.

    PocketWizard)hasbeenreceivingperiodiccallsandreportsfromcustomerswhoareusingtheirCanon

    580EXIIflasheswiththePocketWizardControlTLradiosandexpressingconcernthatperhapstheirflash

    mayhavebeendamagedbyusingaPocketWizardradiotriggerwithit.

    Asofthetimeofthisreport(Jan,2011),thereareabout120140PocketWizardcustomerswhohave

    reportedhavingoneormore580EXIIflashesdamagedwithcommonsymptomsoverthepast18+

    months.

    Ifthefailuremodewasrelatedtoourproduct,thiswouldworkouttolessthan0.5%ofour

    MiniTT1/FlexTT5radio

    units

    which

    were

    connected

    to

    aflash

    that

    failed

    and

    less

    than

    1%

    of

    the

    580EX

    II

    flashesthatwereconnectedweredamaged.

    LPADesignhasconductedaseriousindepthinvestigationforseveralmonthsaswecontinuetocollect

    dataandevidenceofthespecificsofthefailuremode. Inadditionwehavejuststartedtheoutside

    researchassistanceofanalyticalchemistryprofessorGiuseppePetrucciattheUniversityofVermont.

    Research:Thesymptomofthefailureisthatthe580EXIIwillnolongeroutputcontrolledamountsoflight. Itwill

    onlyoutputfullpowerdumps. Thisfullpowerdumpwillhappenevenonapreflash,thereforeleaving

    nostoredenergywithinthecapacitorleftforamainflashexposure.

    ThetestingquicklyrevealedthatanIGBT(transistor)withintheflashisdamaged. Thispartismadeby

    Renesas(part#RJP4301).

    TheIGBTisusedtoturnofftheflowofcurrentthroughtheflashtubewhenthedesiredamountoflight

    hasbeenreached. ThisIGBTisalsousedtocontrol(modulate)thebrightnessofthelightwheninHSS

    (HighSpeedSync)withthehelpofafiberopticcablefeedingalightsensorwithinthemainbody.

    AlthoughLPADesignhasbeenabletoidentifythesymptomoftheproblem,LPADesignhasnotbeen

    abletotracethecauseoftheproblemtoourPocketWizardproductsandwehavenoknowledgeofthe

    incidenceratesofthisproblemarisingindependentlywithoutPocketWizard,i.e.somenumberof580EX

    IIflasheslikelyfailwithoutPocketWizardControlTLradiosinteractingwiththem.Wereceivedreports

    ofthis

    IGBT

    failure

    in

    all

    spectrums

    of

    use.

    It

    spans

    multiple

    different

    Canon

    camera

    models,

    below

    XSyncandaboveinHSS(moreofteninHSS),TTLormanualmodesandonanyversionoffirmwarethat

    thePocketWizardMiniTT1andFlexTT5havehadinpublicrelease. Evenbrandnewflashescouldfail.

    Wehaveruledoutheatbuildupasacausesinceseveralhavefailedwithinthefirstdozenshotsafter

    beingpulledoutofthecamerabag. Thisisallbasedonverbaldescriptionsfromcustomers.

    ItalsohasfailedasmanytimeswithaPocketWizardAC5RFSoftShieldasithasfailedwithoutusingthe

    AC5. SothereappearstobenochangeinoccurrencewhenusingtheAC5orAC7.

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    Wepurch

    otherco

    MostsigOnecom

    replacem

    Theseco

    discharge

    Repaired

    periods

    Soitbeca

    Eventuall

    andsoot

    place.

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    failwitho

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    asedmanyo

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    ificantobseontheme

    ent.

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    fromoneor

    unitsthatha

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    mecleartha

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    builduparou

    entofthefl

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    exampleso

    fthefailedfl

    tsbetween

    vations:asthatALLf

    hemewasth

    moreendso

    eonlytheI

    ectlyonaCa

    ttheIGBTw

    attheflash

    ndthe

    ends

    shheadssol

    ocketWizard

    the580EXII

    ashesfrome

    heunitstha

    ailedflashu

    atALLfailed

    ftheflashtu

    BTreplaced

    oncamera

    snttheonly

    ead(tube/r

    fthe

    flash

    tu

    edthefailur

    radio.

    flashheads

    ndusersso

    failed.

    itshavehad

    unitshavevi

    betotheme

    willfrequen

    ithoutaPo

    failurecom

    flector)was

    be.Sparks

    a

    eproblems

    hatwereca

    ecouldtake

    theIGBTda

    iblesignsof

    talreflector.

    lyfailagain

    ketWizardr

    onentwithi

    alsobadand

    ndelectrical

    ndtheflash

    singIGBTfai

    themapart

    agedandn

    electricalarc

    ithinrelativ

    dioinvolved

    thesystem.

    showedvisi

    arcingwere

    scouldnol

    lurestorepe

    ndstudyth

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    ing/electric

    elyshorttim

    .

    lesignsofa

    pparentlyt

    ngerbemad

    at

    l

    sh

    king

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    Figure1:

    oxidizatio

    Figure2:

    possible

    Figure3:

    housingi

    Flashtubee

    nofmetalre

    Flashtubee

    xidizationof

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    Figure4:

    Figure5:

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    ElectricalWecaptu

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    theIGBT

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    Figure6:

    AnalysisofFredfailuree

    nce,IGBTcu

    mitterlead.

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    Figure7:

    sparkjum

    Closeupvie

    pedtother

    ofIGBTele

    flectorandt

    ctricalsignal

    henintothe

    . Notethat

    collectoroft

    theIGBTgat

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    thenegat

    Figure8:

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    Figure9:

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    Figure10

    the580E

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    FlashTubAnothers

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    shortene

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    Figure11

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