BBK DK1020S - Chapter One about Maintenance; Safety Precautions; Power Supply; Precautions for Antistatic

1.1Safetyprecautions
1.1.1Powersupply
1.1.2Precautionsforantistatic
WhenmaintenancepersonnelarerepairingDVDplayers,heshouldpayspecialattentiontothe
powerboardwith220VACand330VDCwhichwillcausehurtanddamagetopersons!
Movementandfrictionwillbothbringstaticelectricitywhichcausesseriousdamagestointegrated
IC.Thoughstaticchargeislittle,whenalimitedquantityofelectricchargeisaddedtolarge-scale
integratedIC,asthecapacitanceisverysmallinthemeantime,nowtheintegratedICisverymucheasy
tobestruckthroughbystaticelectricityortheperformancewilldecrease.Thusstaticelectricity
preventionisofextraordinaryimportance.Thefollowingareseveralmeasurestopreventstatic
electricity:
1.Useapieceofelectricconductionmetalwiththelengthofabout2metrestoinsertintotheearth,
andfetchtheleadwirefromthetopofthesurplusmetalandconnecttotherequiredstaticelectricity
device.Thelengthanddepthofthemetalembeddedundertheearthshouldbedeterminedaccordingto
thewettabilityofthelocalsoil.Forhumidplaces,itmaybeshorter,andlongeranddeeperfordryplaces.
Ifpossible,itcanbedistributedandlayedintermsof“#”shape.
2.Onoperatingtable-board,theantistatictablecushionshouldbecoveredandgrounded.
3.Alldevicesandequipmentsshouldbeplacedontheantistatictablecushionandgrounded.
4.Maintenancepersonnelshouldwearantistaticwristringwhichshouldbegrounded.
5.Placesaroundtheoperatingpositionshouldalsobecoveredwithelectricconductioncushionor
paintedwithantistaticpaint.
1.Donotstareatlaserheaddirectly,forlaseremissionwilloccurwhenlaserheadisworking,
whichwillhurtyoureyes!
2.Donotusewipingwateroralcoholtocleanlaserhead,andyoumayusecottonswab.
1.1.3Precautionsforlaserhead
ChapterOneAboutMaintenance
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