Teleflex TFX320 Operation Manual page 25

MAINTENANCE AND WARRANTY
TROUBLESHOOTING
7. My unit loses power at high speeds.
Your 320 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 320 displays input voltage in the lower left
corner of the display when it exceeds 15 VDC. 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. The 320 will display the current voltage on-screen if
it is greater than 16 or less than 10 VDC. The voltage readout will appear in
the bottom left corner of the screen.
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.
10. The screen does not display a full fish arch.
Check the running angle of the transducer. If the running angle is too great, a
full fish arch may not appear. Reduce the running angle of the transducer.
Several incremental adjustments may be necessary.
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