Humminbird PiranhaMAX 165 Installation And Operation Manual page 71

the problem, inspect the transducer cable from end to end for breaks, kinks, or cuts in
the outer casing of the cable. If the transducer is connected to the unit through a switch,
temporarily connect it directly to the unit and try again. If none of these actions
identifies an obvious problem, the transducer itself may be at fault. Be sure to include
the transducer if returning the unit for repair.
4. When in very shallow water, I get gaps in the bottom reading and inconsistent
digital depth indication.
The PiranhaMAX will work reliably in water 3 feet (90 cm) or deeper. Remember that the
depth is measured from the transducer, not from the surface of the water.
5. The unit comes on before I press the POWER-MENU key, and won't turn off.
Check the transducer cable — if the outer jacket of the cable has been cut and the
cable is in contact with bare metal, you will need to repair the cut with electrical tape.
If there is no problem with the cable, disconnect the transducer from the unit and see
if the problem is corrected, to confirm the source of the problem.
6. I get gaps in the reading at high speeds.
Your transducer needs adjusting. If the transducer is transom-mounted, there are two
adjustments available to you: height, and running angle. Make small adjustments and
run the boat at high speeds to determine the effect. It may take several tries to optimize
high-speed operation. This can also be a result of air or turbulence in the transducer
location caused by rivets, ribs, etc.
7. My unit loses power at high speeds.
Your PiranhaMAX 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.
8. The display begins to fade out. Images are not as sharp as normal.
Check the input voltage. The PiranhaMAX 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 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 also appear as noise on
the display. If the transducer is mounted too close to the propeller, the turbulence
generated can interfere with the sonar signal. Make sure that the transducer is mounted
at least 15" (380 mm) from the propeller.
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Troubleshooting