Topic: SI images sometimes comes in brighter and darker strips.

[Rotus623]

Anyone notice this? Not really much of a problem, but if I am scanning Ill notice that the screen will get brighter or darker from one strip and then continue at that brightness for a while, then it will switch back. What does this sound like is going on?

[RGecy]

Can you get a screenshot for us when this happens?  Are you changing between frequencies when this happens?

Robert

[Rotus623]

I can try and get a screenshot of it. I am not changing frequencies, but I do have the unit hooked up to my main motor battery, with a 12V regulator just in front of the unit. I am constantly around 12.5V. And just to clarify, what will happen is the screen will be bright, and then all of the sudden the new info that is feeding from top to bottom will turn a different shade or brightness, and all the new info will stay at that brightness. Then after some time it will shift back to the other "shade" if you will. I need to determine if it does this when the main motor is on or off.

[rnvinc]

Is this shift in the screen brightness/darkness a "gradual shift" ...like would be seen as the boat moves over changes in bottom hardness...??

Or is this shift in screen brightness/darkness a "sudden big shift"...like would be seen if the frequency was changed in mid scroll...??

Rickie

[Rotus623]

Sudden big shift as if I manually changed the brightness.

[rnvinc]

Sudden big shift as if I manually changed the brightness.

This doesn't sound normal...

Do you know anyone with a SI unit that you can try your head unit on their boat ...and then their head unit on your boat...??

Rickie

[Rotus623]

This doesn't sound normal...

Do you know anyone with a SI unit that you can try your head unit on their boat ...and then their head unit on your boat...??

Rickie

Nope. But if I have to I will send the unit back to bird and get an upgrade to an 899.

Seriously though, I have not idea where to start. It doesnt really cause me any harm, I would just like to make sure it wont haunt me in the future. Does anyone think it has something to do with the in line voltage regulator that I have? It is designed to keep the voltage at or above 12v when the starter motor is turning, and also to shunt any voltage spikes. I wonder if it has something to do with capacitor discharge of the 12v regulator. Maybe I will try running the unit without the regulator next time I go out. I just have to remember to turn the unit off before firing the big motor up.

Does that sound like a possibility?

[rnvinc]

There's really no reason to run a regulator...

I think the units are spec'd at something 11-18v....

Rickie

[Humminbird_Greg]

I would try it and see or try connecting it to a stand-alone battery.

[Rotus623]

Ill give it a whirl!

[Rotus623]

So I did a little trial and error fellas. When I am running the trolling motor with SI I have no issues. When I am running the engine at a relatively constant speed I have no issues with side imaging at all. If I punch it or change the RPMs really quickly sometimes it will produce the bright/dark dilemma, although it is manageable and really causes me no harm.

So if y'all hear of this in the future, it is a form of electrical interference.

[RGecy]

I am on my phone right now trying to type this reply but I thought I would make it short and sweet. If you do a search on the forum here for trolling motor interference you should come up with quite a few posts. Hummingbird mates a trolling motor interference kit as well.

Good luck

Robert

[Humminbird_Greg]

I just relied to your other post Rotus.
Check for motor interference the same way but have the Si sonar up to see if it is what is causing this or not.
“You should be able to check for motor interference by taking the motor out of gear and revving it to the same RPM level…”

[Rotus623]

Cool thanks Greg.