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GNS 400W Series Maintenance Manual
Page 1-1
190-00356-05
Rev. A
SECTION 1
INTRODUCTION
This manual contains maintenance information for the GNS 400 “W” (WAAS) series of units. All
units in the GNS 400W series affected by this manual are listed in the table on page iii.
1.1 MAINTENANCE/SUPPORT
PHILOSOPHY
Avionics shop repair is limited to replacing the parts listed in Section 6. All repairs can be made
at the bench with an appropriate replacement spare part. Faulty parts listed in Section 6 (or a
complete unit) can be returned to Garmin for repair. For information pertaining to spares
stocking (suggested quantities, etc.) contact Garmin at one of the addresses listed on the inside
cover.
This manual is written for field shops not equipped with Garmin Automated Test Equipment
(ATE) and not having access to Garmin proprietary repair documentation. Component level
repair is not authorized. Send the unit to Garmin for repair when any troubleshooting, testing, or
repair falls outside the scope of this manual (paragraph 1.3).
1.2 UNIT
UPGRADES
This manual does not contain procedures for upgrading “legacy” GNS 400 series units to WAAS
units. Contact Garmin aviation product support for upgrade information and instructions. If field
shops should encounter a WAAS upgraded unit, refer to the table on page iv which lists all
upgrade part numbers.
1.3 FACTORY
REPAIR
A "Return Merchandise Authorization" (RMA) number must be requested from Garmin before a
unit is returned. Units returned without an RMA will be refused and returned at the sender's
expense. Send units with assigned RMA numbers to the following address:
Garmin International, Inc.
Factory Repair
1200 E. 151st St.
RMA Number: _______
Dock Door #1
Olathe, KS 66062