FT-991A_serv维修手册含电器原理图

YAESUTechnical SupplementThe radioHF/VHF/UHF ALL MODE TRANSCEIVERFT-991AEHO67M90B2017 YAESU MUSEN CO..LTD.IntroductionThis manual provides the technical information necessaryfor servicing the FT-991A HF/VHF/UHF ALL MODEContentsTRANSCEIVERSpecificationsServicing this equipment requires expertise in hand-ing surface-mount chip components.Attempts by non-Exploded View Miscellaneous Partsqualified persons to service this equipment may resultBlock Diagramin permanent damage not covered by the warranty,andConnection Diagrammay be illegal in some countries.AlignmentTwo PCB layout diagrams provided for each double-Board Unit(Schematics,Layouts Parts)sided board in this transceiver.Each side of the boardMAIN Unitis referred to by the type of the majority of componentsPLL Unitinstalled on that side ("Side A"or "Side B").In mostcases one side has only chip components,and the otherEDSP Unithas either a mixture of both chip and leaded componentsCNTLUnit(trimmers,coils,electrolytic capacitors,ICs,etc.),orHF-PA Unitleaded components only.V U-PA UnitWhile we believe the information in this manual to bePANEL Unitcorrect,YAESU assumes no liability for damage thatTUNER Unitmay occur as a result of typographical or other errorsthat may be present.Your cooperation in pointing outJACK Unitany inconsistencies in the technical information wouldSCP Unitbe appreciated.DSP UnitImportant 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.