My 787hummingbird fish finder turns dark around the edges of the screen after in use for a while when I turn it off for a while & turn it on its clear then it dose it again

Battery too low
Fuse blown
Corroded connections at battery, fuse, connector
Dead fish finder

If you turn on the "fish I.D. mode" in your sonar options then you will be able to turn on the fish alarm as well. Lowrance HDS 5x Gen2 Fishfinder
This a link to a pic file for your owners manual.
Go to page 67 to, see how to access and enable/disable alarms for your unit.

Call our Customer Service Group at 800-633-1468 and they should be able to help you.


Joby
Humminbird

Pls. turn the little knob near the finder untill you get clear picture inside finder, previous owmer might have turn the knob for his eye sight good luck.

Goes dark or just stays dark ? if stays dark then it is the GPU causing problems as it has got too hot at some point, possibly due to lack of ventilation underneath. What sometimes works for me is to turn the machine on and flip it over and rest it on say a tea towel, but have the screen overhang the edge of table so it doesnt damaged it. Then, you need to cover vents and let the machine heat up for say around 10 mins. After this time, turn machine off and back on again, and you will find the screen will come back on. You should then be able to use machine as normal, but keep all vents clear. Some folk might think this is barmy, but trust me it works on most, HP, Compaq, Dells etc.

Hi there.

Ok in WIDE beam mode the cone extends out 45 degrees from the transducer. This covers a fair area, but is best used only in shallow waters as the beam may not have enough power to penetrate deeper waters effectively. 30ft should be fine for WIDE mode however. Using a bit of trigonometry, the beam would extend to a diameter of 60 feet from the center point of the transducer on the sea/river floor.

The beam is a direct beam... It is not a rotational beam from the transducer... i.e. it does not rotate like a radar beam but shoots downward in the cone arc constantly. Imagine a torch being turned on and off very rapidly... The light shoots straight out from the torch in its own cone shape. This is essentially what the transducer does when it shoots out a signal every millisecond or so.

The image you see on the screen is the result of the hole cone of signals, however, the strongest sonar returns occur near the center of the beam. Weaker returns are shown which are located towards the outer edges of the sonar cone where the signal power is less. So if a fish passes right on the edge of the beam, it will only show up as maybe 1 pixel on the sounder screen as it is a weak return on the edge of the sonar cone, whereas if that fish passes under the center of the beam, it will show a larger, more continuous or arched shaped return as the fish moves from the outside of the beam, through the center of the beam, and out to the other edge of the beam under the boat.

Regarding the flasher... I would advise not to use this. It does work by showing a continuous top and bottom reading which displays as constant flashes around the circle readout. Anything it picks up in the beam will show as flashes in between the top and bottom readings. Using the display is far better and with practice allows you to better identify fish and bottom structure readings. Flashers were earlier forms of sonar readouts. Some older folk still like them but I believe the normal display is better for finding and identifying fish and can show structure shape as well (the flasher mode really cannot).

Hope that helps!

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Hummingbird will refurbish that one for around 150US dollars, better then 500+ for a new one. If the screen is subjected to direct sunlight and heats up it can go out. This is why they discontinued the 67 model and replaced it with the 767.

Check any magnet or some speaker are near ur tv . Off it for 1 hrs , re on it & check

fish finder transducer needs to be on before you boot your system. check your hsb cables and termination