Cyrus CD T - SMD COMPONENT REPLACEMENT; Handling; Static precautions; Soldering;desoldering SMD components

SMDCOMPONENTREPLACEMENT
©CyrusAudioLtdJun2014 2 CDt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 Lead free
SMDrework.MostSMDcomponentswillwithstand370ºCfor5to10seconds