FT-991_serv维修手册含电器原理图

YAESUTechnical SupplementThe radioHF/VHF/UHF ALL MODE TRANSCEIVERFT-991EHO57M90B2015 YAESU MUSEN CO..LTD.IntroductionContentsThis manual provides the technical information necessaryfor servicing the FT-991 HF/VHF/UHF ALL MODESpecificationsTRANSCEIVERExploded View Miscellaneous PartsServicing this equipment requires expertise in hand-Block Diagraming surface-mount chip components.Attempts by non-Connection Diagramqualified persons to service this equipment may resultAlignmentin permanent damage not covered by the warranty,andBoard Unit(Schematics,Layouts Parts)may be illegal in some countries.Two PCB layout diagrams provided for each double-MAIN Unitsided board in this transceiver.Each side of the boardPLL Unitis referred to by the type of the majority of componentsEDSP Unitinstalled on that side ("Side A"or "Side B").In mostCNTL Unitcases one side has only chip components,and the otherHF-PA Unithas either a mixture of both chip and leaded componentsV_U-PA Unit(trimmers,coils,electrolytic capacitors,ICs,etc.),orleaded components only.PANEL UnitWhile we believe the information in this manual to beFAN-CNTL Unitcorrect,YAESU assumes no liability for damage thatTUNER Unitmay occur as a result of typographical or other errorsJACK Unitthat may be present.Your cooperation in pointing outDSP Unitany 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.