15
MESSAGE (cont.)
RECOMMENDED REPAIR (cont.)
No GPS reception
Check Date/Time Page for correct UTC time
1
Check Position Page for close approximate starting
position (within 300 nautical miles)
2
Replace Antenna and/or antenna cable
Replace GPS Receiver Board (see Section 3.2.5)
Replace CPU Board (see Section 3.2.4)
Unit displays velocity
when not moving
3
Replace GPS Receiver Board (see Section 3.2.5)
Ni-Cad Battery life is
short or Ni-Cad battery
mop (Operational Remote
Battery)
Replace External Battery Pack
Replace CPU Board (see Section 3.2.4)
Unit loses memory in
spite of new memory
battery
Replace CPU Board (see Section 3.2.4)
Unit does not detect low
memory battery
Replace CPU Board (see Section 3.2.4)
Unit does not detect
external power
4
Check external power connection
Replace CPU Board (see Section 3.2.4)
No serial data output
Replace CPU Board (see Section 3.2.4)
No external CDI output
or external CDI functions
improperly
Check connections and verify operation in Test Mode
(see Section 4.2.3)
Replace CPU Board (see Section 3.2.4)
Unit detects low NICAD
battery too soon or too
late
Adjust battery alarm setpoint from config. page
1
If UTC Time is incorrect, unit may be reset by holding the CLR key down while turning the unit on. The
unit must then be attached to an antenna, allowed to search the sky and collect new almanac data. This
process may take 20-30 minutes. CAUTION: All user waypoints/settings will be lost if the unit is reset.
2
The GNC 250/300 will eventually perform an AutoLocate™ and lock onto satellites, however this can add an
additional 10 minutes to the normal lock-on time.
3
Display of low velocity numbers when not moving can occur when the units is in 2D mode and should not
be considered a problem. However, this should seldom occur in 3D mode.
4
The “Turning Off” message appears at/ below approximately 9 VDC external power.
