FT-891_维修维护电器原理图手册_2017

YADSUTechnical SupplementHF/50MHz TRANSCEIVERFT-891EH065H90D2017 YAESU MUSEN CO..LTD.IntroductionContentsThis manual provides the technical information necessaryfor servicing the FT-891 HF/50MHz TRANSCEIVER.SpecificationsServicing this equipment requires expertise in hand-Exploded Viewing surface-mount chip components.Attempts by non-Block Diagramqualified persons to service this equipment may resultConnection Diagramin permanent damage not covered by the warranty,andAlignmentmay be illegal in some countries.Board Unit(Schematics,Layouts Parts)Two PCB layout diagrams provided for each double-MAIN Unitsided board in this transceiver.Each side of the boardis referred to by the type of the majority of componentsLOCAL Unitinstalled on that side ("Side A"or "Side B").In mostPA Unitcases one side has only chip components,and the otherDSP Unithas either a mixture of both chip and leaded componentsPANEL Unit(trimmers,coils,electrolytic capacitors,ICs,etc.),orSW-A Unitleaded components only.While we believe the information in this manual to beSW-B Unitcorrect,YAESU assumes no liability for damage thatVR Unitmay occur as a result of typographical or other errorsthat may be present.Your cooperation in pointing outany inconsistencies in the technical information wouldbe appreciated.Important NoteThis transceiver was assembled using Pb(lead)free solder,based on the RoHS specification.Only lead-free solder(Alloy Composition:Sn-3.0Ag-0.5Cu)should be used for repairs performed on this apparatus.The solder statedabove utilizes the alloy composition required for compliance with the lead-free specification,and any solder with the above alloy com-position may be used.CautionRisk ofexplosion if battery is replaced by an incorrect type.Dispose of used batteries according to the instructions.