Garmin GNC 420 Maintenance Manual page 51

1. Remove the Main Board (paragraph 4.5.5).
2. Remove all electrical grounds from the unit, so if using a grounded tip soldering
iron, the battery will not be shorted upon removal.
3. Unsolder the battery leads from the bottom side of the Main Board.
4. Carefully remove the battery by pulling it out from the topside of the Main Board.
The battery leads are welded to the battery and cannot be removed.
5. Install a new battery and solder the leads from the bottom side of the Main Board.
6. Reinstall the Main Board.
7. Turn the unit on.
8. Verify the Memory Battery Low message does not appear.
9. Turn the unit off and carefully turn the unit over.
10. Verify the memory battery voltage (measure from positive side of the battery to
ground) is at least 2.9 VDC.
______OK
Page 4-8
Rev. C
400 SERIES MAINTENANCE MANUAL
P/N 190-00140-05