Vertex Standard VX-820 series, Service Manual

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1
Contents
Specifications ...................................................................................................................................................... 2
Exploded View & Miscellaneous Parts .......................................................................................................... 3
Block Diagram .................................................................................................................................................... 5
Circuit Description ............................................................................................................................................. 7
Alignment .......................................................................................................................................................... 11
Board Units (Schematics, Layouts & Parts)
Main Unit .................................................................................................................................................... 15
Display Unit ................................................................................................................................................ 33
Cable Unit.................................................................................................................................................... 41
©2005 VERTEX STANDARD CO., LTD. EC058N90A
VHF Band
Service Manual
VX-820 Series
Introduction
This manual provides the technical information necessary for servic-
ing the VX-820 Series Transceiver.
Servicing this equipment requires expertise in handing surface-mount
chip components. Attempts by non-qualified persons to service this
equipment may result in permanent damage not covered by the war-
ranty, and may be illegal in some countries.
Two PCB layout diagrams are provided for each double-sided board
in this transceiver. Each side of the board is referred to by the type of
the majority of components 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.
As described in the pages to follow, the advanced microprocessor de-
sign of the VX-820 Series Transceiver allows a complete alignment of
this transceiver to be performed without opening the case of the radio;
all adjustments can be performed from the front panel, using the “Align-
ment Mode” menu.
While we believe the information in this manual to be correct, VER-
TEX STANDARD assumes no liability for damage that may occur as a
result of typographical or other errors that may be present. Your coop-
eration in pointing out any inconsistencies in the technical information
would be appreciated.
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 EUROPE B.V.
P.O. Box 75525, 1118 ZN Schiphol, The Netherlands
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