Intermittent Lowrance Sonar Readings

[bulletbob08]

I'm having troubles with the sonar on my 07 model Lowrance 522c igps and 02 model X91 The 522c has a Navionics chip. The GPS on the 522 works fine. However, both units lose the depth reading (flash, lock-up, or display a ridiculous depth) although the problem is more pronounced on the 522. On the 522 this happens when the boat is at the dock or moving. The X91 reads correctly at the dock but sometimes also loses depth when underway. There is no discernable pattern at different speeds and water conditions (occurs sometimes at idle, full throttle & every where in between) and at different motor trim & running positions. Sometimes both read correctly & at other times only one unit displays corrrectly and at other times both units do not read the depth. The transducers are mounted about 5" apart on a 2002 Lund Pro V SE with a Yamaha four stroke, are well underwater and in a position not subject to boat or motor interference. The units are located on the driver's console in close proximity to each other. Both are wired to the main motor battery with fuses located near the battery. The boat has a master power switch to turn them on. The problem occurs whether one unit is on or both. Here's what I've tried with no success:
- Moving the angle of the transducers
- Tightening all connections multiple times at the battery and at the units
- Checked the fuses at the battery
- Battery is fully charged and units are operating within specified voltage perimeters
- Switching the transducers between the two units
- Transducers are clean and free of any damage. Audible sound when the they are operated on the trailer
- Checked for visible cut or pinched wires
- Adjusted ping speed
- Adjusted sensitivity
- Adjusted noise suppression
- Defaulted to factory settings
- Did a soft reboot
- Switched load locations in the boat
- Running with different electrical systems (bilge, live well) on or off.

The 522 has version 1.4.0 software which I will upgrade to 2.3.0 but since the issue is occuring with both units I'm dubious this will have any effect

I'm at wits end & would appreciate any help. Thanks

 

[octane]

Re: Intermittent Lowrance Sonar Readings

I also have the same problem with my lowrance depth gauge. sometimes it will lockup and flash the same number for a while, and sometimes it will display a number that makes no sense at all (like 0.2 feet)

I can't find any relation to speed or water condition to explain this.

 

[Silvertip]

Re: Intermittent Lowrance Sonar Readings

Have you tried running just one device at a time to verify that there is no interference between them. Transducers 5-inches apart and/or on the same frequency may be the issue. Parallel running transducer lines and transducer lines running along side of other wiring can create issues as well. Transducer "kick-up" tension adjusted properly so the transducer doesn't pivot up at speed?

 

[Boatist]

Re: Intermittent Lowrance Sonar Readings

I agree with silver. It will never work with both units on at the same time, turn one off.

If you can mount the transducers about 20 feet apart then it can work in shallow water up to about 30 feet.

Anytime the cone angle of two transducer on the same frequency overlap then niether unit will work. Turn one unit off and the other will work.

 

[bulletbob08]

Re: Intermittent Lowrance Sonar Readings

I experience the problem with just one sonar active (the other unplugged). Also, I've checked that the transducers are not popping up. Yet the problem remains.

I updated the 522 software from 1.4.0 to 2.3.0 but since both the 522 & X91 are experiencing problems I doubt this will resolve the issues.

I greatly appreciate your thoughts & would welcome any further ideas.

 

[Silvertip]

Re: Intermittent Lowrance Sonar Readings

It is highly unusual that both units exhibit this problem even operating individually. Does this problem occur whether or not the engine is running and with only one unit or the other in operation? If it does, power and transducer cable routing is not the issue. If they operate normally with the engine off, you found the problem. Power and/or transducer wires are routed too close to the engine harness and will need to be rerouted or shielded. Modern engines have high-energy ignition systems so it is also possible that can be an issue although not if they misbehave with the engine off. Do you have any other accessories on the boat that are running when this happens. Noisy live well pumps can create electrical interference that can cause issues. Even if you have a cell phone on, turn it off and see what happens. Grasping at straws here but there has to be a logical answer and generally the answer turns out to be something simple. If you have a cell phone charger plugged in, they can create interference.

 

[bulletbob08]

Re: Intermittent Lowrance Sonar Readings

Poor reading occur at dock with engine off. However, due to the shallow depth (2') it's hard to tell if it's the shallow water or electrical interference from the engine.

All other systems (bilge, cell phone, etc) are off.

Again thanks for the guidance. Will try again at Lake of The Woods this weekend (scary w/ intermittent depth finder).

 

[Silvertip]

Re: Intermittent Lowrance Sonar Readings

So the interference has been noted only in two feet of water at the dock? That little tidbit of information would have been nice to know up front since sonar doesn't work well in two feet of water! There are rocks the size of Volkswagens in Lake of the Woods. Don't rely on the sonar to warn you of them. By the time the locator shows it you will already have hit it. I used to go in at the Northwest Angle (Angle Inlet) and then run out 17 miles to Spruce Island. Fished the Tug Channel.

 

[Boatist]

Re: Intermittent Lowrance Sonar Readings

Are the transducer mounted where you have green water under the boat not out near the chines. About 12 inches to starboard side of engine is a good starting place. At least one half of the transducer needs to be below the hull on the deep side. Also the transducer must point straight down. Do you have a good size electrical power wire going to the units?
Are the transducer mount on the lowest hull or do you have a steped hull?
A picture or two would be great.