Yaesu FT-277R Manual

FT-277R
Technical Supplement
©
2010 VERTEX STANDARD CO., LTD.
Specifications ....................................................................................................................................................................2
Exploded View & Miscellaneous Parts .......................................................................................................................3
Block Diagram .................................................................................................................................................................. 5
Circuit Description .......................................................................................................................................................... 7
Alignment ..........................................................................................................................................................................9
Board Units (Schematics, Layouts & Parts)
Main Unit ................................................................................................................................................................... 13
FTD-7 DTMF Paging Unit (Option) ........................................................................................................................ 31
FT-277R Technical Supplement
EH022U91A
Introduction
This manual provides the technical information necessary for servicing the FT-
277R UHF FM Transceiver.
Servicing this equipment requires expertise in handing surface-mount chip compo-
nents. Attempts by non-qualified persons to service this equipment may result in
permanent damage not covered by the warranty, and may be illegal in some coun-
tries.
Two PCB layout diagrams are provided for each double-sided board in this trans-
ceiver. Each side of the board is referred to by the type of the majority of compo-
nents installed on that side ("Side A" or "Side B"). In most cases one side has only
chip components (surface-mount devices), and the other has either a mixture of
both chip and leaded components (trimmers, coils, electrolytic capacitors, ICs, etc.),
or leaded components only.
While we believe the information in this manual to be correct, VERTEX STANDARD
assumes no liability for damage that may occur as a result of typographical or other
errors that may be present. Your cooperation in pointing out any inconsistencies in
the technical information would be appreciated.
The 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 stated above utilizes the
alloy composition required for compliance with the lead-free specification,
and any solder with the above alloy composition may be used.
Contents
VERTEX STANDARD CO., LTD.
4-8-8 Nakameguro, Meguro-Ku, Tokyo 153-8644, Japan
VERTEX STANDARD
US Headquarters
10900 Walker Street, Cypress, CA 90630, U.S.A.
YAESU UK LTD.
Unit 12, Sun Valley Business Park, Winnall Close
Winchester, Hampshire, SO23 0LB, U.K.
VERTEX STANDARD HK LTD.
Unit 5, 20/F., Seaview Centre, 139-141 Hoi Bun Road,
Kwun Tong, Kowloon, Hong Kong
VERTEX STANDARD AUSTRALIA PTY., LTD.
Normanby Business Park, Unit 14/45 Normanby Road
Notting Hill 3168, Victoria, Australia
Important Note
1