Garmin APOLLO GX SERIES, Service Manual

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Garmin AT Rev --
6-4 GX Service Manual © 2004 Garmin AT
altitude input is required for installations approved for non-precision approach operation. It is optional
for other installations. The GX50/60/65 altitude input can be connected from either an altitude
encoder/converter or an air data converter.
Dual Uart Serial Interface
The GX50/60/65 includes two RS-232 serial ports for making optional connections. The serial ports
can be used for connecting to such devices as the Apollo SL40 communication, a moving map
display, or an altitude encoder/converter.
Power Supply
The GX60/65 requires two power connections, one for the GPS navigation computer board (P701,
DB37) and one for the communications transceiver board (P400, DB15). The GPS navigation
computer board power input is internally fused at 3 amps. A separate 2 amp (maximum) circuit
breaker or fuse should be installed externally for overload or short circuit protection. The
communications transceiver board power input (GX60/65 only) is internally fused at 7 amps. A
separate 5 amp (maximum) circuit breaker or fuse should be installed externally for overload or short
circuit protection.
The GX50 requires only a power connection for the NAV board (P701) like the GX60/65.
The GX55 requires only a power connection to the 14-pin rear connector.
Front Panel E.L. Graphics Display
The display assembly (UPS Aviation Technologies part no. 145-2341-00) is a custom front panel
consisting of an electroluminescent panel producing an emissive amber display. The EL Display is
mounted on an application specific secondary circuit board containing the display controller, power
supply, dual rotary encoder, volume/power knob, carbon ink contact pad patterns for the 7 push
buttons, 7 LEDs, one photocell and one thermistor.
The display is a 100 fL areal brightness (at 360 Hz) electroluminescent flat panel with a dot pitch of
0.40 mm (64 DPI), a display matrix of 160 by 80 addressable pixels and a pixel aspect ratio of 1:1
(V:H). The assembly includes the DC-DC converter necessary to generate the special voltages used
by an EL display, and includes an 8-bit wide microprocessor interface.
A photocell located in the top left corner of the front panel automatically controls the light intensity of
the display according to ambient light conditions.
The NAV board power supply pr12.5 VDC to the display assembly DC-DC converter (P202
Pin 1) and +5 VDC to the display assembly digital logic (P202 pin 5).
Service and troubleshooting of the display assembly are limited to whole unit replacement.