Insignia DUAL BEAM 250DX - Manual (Page 31)

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7. My unit loses power at high speeds.
Your 250DX has over-voltage protection that turns the unit off when input
voltage exceeds 20 VDC. Some outboard motors do not effectively regulate the
power output of the engine’s alternator and can produce voltage in excess of 20
volts when running at high RPMs. The 250DX displays input voltage in the
Diagnostic screen. Use this readout to determine if the voltage exceeds 20 VDC.
8. The screen begins to fade out. Images are not as sharp as normal.
Check the input voltage using Diagnostic. The 250DX will not operate on input
voltages below 10 VDC.
9. The display shows many black dots at high speeds and high
sensitivity settings.
You are seeing noise or interference caused by one of several sources.
Noise can be caused by other electronic devices. Turn off any nearby
electronics and see if the problem goes away. Noise can also be caused by
the engine. If engine noise is causing the interference, the problem will
intensify at higher RPMs. Increase the engine speed with the boat
stationary to isolate this cause. Propeller cavitation can appear as noise on-
screen. If the transducer is mounted too close to the propeller, the
turbulence generated can interfere with the sonar signal. Ensure that the
transducer is mounted at least 15" (38cm) from the prop.
MAINTENANCE
TROUBLESHOOTING