Maintenance

Boat Speed/Water Temperature Connection. Other connections tested include the boat speed and surface water temperature sensors. These accessory sensors can be purchased independently or together as a single sensor (see the Humminbird Accessories catalog). If the sensors are connected and working properly, a “connected” message appears.

The speed input feature only works when the boat is in motion as the paddle wheel on the speed sensor must rotate to be detected.

Voltage Input. Another connection tested is the voltage input, and is especially helpful in diagnosing input voltage problems. The current input voltage is displayed. If voltage fluctuations or power supply in excess of 20 VDC or less than 10 VDC is suspected, use the diagnostic screen to confirm input voltage. Often, small outboard motors do not effectively regulate voltage when operated at high engine speeds.

Use Diagnostic while running the boat at high speeds to show the voltage gain. Also, if you are using the 250DX in portable configuration or from the trolling motor battery, Diagnostic can be used to evaluate the health of the battery by showing the current voltage.

Total Time. The total time category indicates the total time the unit has been in use since shipped from the factory. It is normal for some hours to appear in the total time when the unit is new due to factory testing. While this is often of interest to the user, it is primarily a diagnostic tool for the repair technician should the unit need service.

MAINTENANCE

Your 250DX is designed to provide years of trouble free operation with virtually no maintenance. Follow these simple procedures to ensure your 250DX continues to deliver top performance.

•If the unit comes into contact with salt spray, simply wipe the affected surfaces with a cloth dampened in fresh water. Do not use a chemical glass cleaner on the lens. Chemicals in the solution may cause cracking in the lens of the unit.

•When cleaning the LCD protective lens, use a chamois and non-abrasive,