Garmin 400W Series Instructions Manual page 13

Item Interval
Every 2000
GPS Antennas flight hours or
(Only if antenna ten (10)
is installed by years,
this STC) whichever is
first
Every 2000
flight hours or
HTAWS
ten (10)
Annunciators (if
years,
installed)
whichever is
first
2.5.1 Cleaning the Front Panel
The front bezel, keypad, and display can be cleaned with a soft cotton cloth dampened with clean water.
DO NOT use any chemical-cleaning agents. Care should be taken to avoid scratching the surface of the
display.
2.5.2 Display Backlight
The display backlight lamp is rated by the manufacturer as having a usable life of 20,000 hours. This life
may be more or less than the rated time depending on the operating conditions of the 400W Series unit.
Over time, the backlight lamp may dim and the display may not perform as well in direct sunlight
400W Series
Instructions for Continued Airworthiness Bell 407
Description/Procedure
Perform an electrical bonding test on antennas installed by this
STC:
1. Disconnect coaxial cable(s) from the antenna connector(s).
2. Measure the resistance between the antenna connector and
a nearby exposed portion of the antenna foil ground plane.
3. Verify the resistance is equal to or less than 10 milliohms.
4. Reconnect the coaxial cable(s) to the antenna connector(s)
and ensure it is secured.
In the event of bonding test failure, remove antenna, and clean
and prepare the hardware mating surfaces as follows:
Clean countersunk areas of the antenna. Clean countersunk
areas using an approved solvent per Bell Specification BHT-
ELEC-SPM, CHP 8.
Reinstall using unit replacement procedures contained in the
installation drawing listed in paragraph 2.1 of this document. Any
reworked antenna installation shall have a resistance of less than
or equal to 2.5 milliohms.
Perform an electrical bonding test:
1. Measure the resistance between the metallic body of each
Vivisun annunciator and the console assembly and verify
that the resistance is less than or equal to 20 milliohms.
In the event of bonding test failure:
1. Inspect the grounding strap which is installed between the
annunciator panel and the instrument panel. Ensure that the
fastener hardware is secure and that the strap is not
damaged. If damaged, replace the bonding strap. For
annunciator installation with annunciator mounted in
instrument panel verify mating surfaces are clean and free
of corrosion.
2. If problem persists, remove the bonding strap and clean the
mating surfaces of the bonding strap and
annunciator/instrument panel per Bell specification BHT-
ELEC-SPM CHP8. For installations with the annunciator
mounted in instrument panel clean the mating surfaces.
3. Reinstall the bonding strap (or annunciator when mounted
in instrument panel) and verify that the resistance between
the annunciators and the console assembly after prepping
bonding surface is less than 10 milliohms.
190-01226-14 Rev. 3
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