Hlau saum npoo yuav tsum du thiab tsis raug corroded los ntawm xeb.Plating yuav tsum tsis txhob crease los yog tev tawm.Plastic casing yuav tsum tsis txhob yuav uneven, crude los yog tej kab nrib pleb los yog puas.Lub rwb thaiv tsev ntawm qhov sib txawv ntawm cov khoom siv hluav taws xob yuav tsum dais qhov kev ua haujlwm ntawm kev sim voltage thiab muaj
tsis muaj punctures rau nws.
90% ntawm qhov chaw yuav raug them los ntawm solder.Tsis muaj deformation ntawm lub hauv paus,
tuaj yeem ua tau raws li kev siv tshuab, hluav taws xob.Action tsis thaiv
phenomenon, khawm tso cai rau hnav nto