Black Screen When Connected to Built-in MEGA DI

There could be a few reasons for this:

1. Has the Humminbird software been updated? G2N models for instance, require an update to function correctly with the Built-in MDI. You can find the latest update for your Humminbird unit at https://humminbird.johnsonoutdoors.com/us/support/software-updates
    
2. Verify that the "Connected Transducer" setting in the "Sonar" menu is set to Built-In HW : MDI+.
    
3. Check the transducer adapter cable connection to ensure there is no loss of signal. Check the transducer connection in the control box as well.
    
4. If the Built-in MDI transducer is not submerged in water, the Humminbird screen will appear black (it could also display as white, green, red or blue depending on the background color you have selected). When the trolling motor is in the stowed position and the Humminbird is powered on, the unit will continue to ping and search max depth which puts several seconds between pings. It is recommended to turn the Humminbird sonar off while the trolling motor is stowed or the transducer is out of the water. Not only will this save power and minimize your hours on the control head and the transducer but it will also keep your unit from having to reacclimate to the water and reduce the amount of time it takes to find the bottom again. To do this, press the power key during operation. A menu will appear that will allow you to turn the sonar on/off.