Cyrus 6 DAC - SMD COMPONENT REPLACEMENT; Handling; Handling SMD ICs; Measuring circuits with SMD capacitors and resistors

SMDCOMPONENTREPLACEMENT
©CyrusAudioLtdJun2014 5 Cyrus6DAC,Cyrus8DACservicemanualIssue1
Handling
SMD resistors andcapacitors are widely used inthe Cyrus rangeof products.When handling
SMDcomponents,certainprecautionsshouldbeobserved‐
HandlingSMDresistorsandcapacitors
 AlwaysstoreSMDcomponentsintheiroriginalpackagingorinacooldryenvironment.
 AlwayshandleSMDresistorsandcapacitorswithtweezersoravacuumpencil.
 NeverhandleSMDresistorsandcapacitorswithfingers.
 HoldtheSMDcomponentbythebody,notbytheends.
 DonotuseSMDresistorsorcapacitorsiftheendsaredirtyordiscoloured.
 Donot use SMDresistorsorcapacitorsif they havebeendroppedonthefloor‐ they may
beinternallydamaged.
 Alwaysusereplacementcomponentsofthe correct size and shape. SMDcomponentsare
availableinmanydifferentpackages.Wherepossible,orderoriginalpartsfromCyrus.
HandlingSMDICs

 Alwaysstorethesecomponentsintheiroriginalpackagingorinacooldryenvironment.
 AlwayshandleSMDtransistorsandICswithtweezersoravacuumpencil.
 NeverhandleSMDtransistorsandICswithfingers.
 Ensure that the connection pins of larger multi‐pin ICs are not
deformed or damaged
beforefitting.
MeasuringcircuitswithSMDcapacitorsandresistors
 Avoidusingsharp,pointedprobesdirectlyonthecomponentendcaps.
 MeasurevoltagesfromthePCBpadnexttothecomponent.
Staticprecautions
SMD components, particularly ICs, may be damaged by the static levels present in the
workshop. Damage causedbystaticmay not immediatelycausecomponentfailure but could
cause partial damage and a possible failure  in the future. Observing these simple SMD
precautionswillavoidproductfailuresrelatedtostaticdamage‐
 Alwayswearagroundedwristbandwhenreplacinganyelectroniccomponents.
 Alwaysstorecomponentsintheiroriginalpackagingorconductiveplasticbags.
 Neverstorecomponentsinplastictraysorbagswithoutprotection.
Soldering/desolderingSMDcomponents
 Neverre‐useoldSMDcomponentsafterde‐soldering!
 Always apply solder heat directly to the contact area. Avoid over‐heating adjacent
components.
 AlwaysrepairSMDPCBswiththecorrecttools.SMDcomponentscanonlybereplacedwith
a hot air pencil or soldering iron designed for SMD components, preferably with
temperaturecontrol.
 Keepthesolderingtemperatureaslowaspossible.370ºCisrecommendedforSMDrework
onPCBsthatuselead‐freesolder.MostSMDcomponentswillwithstand370ºCfor5to10
seconds