Bad Trandsucer or setting issue?

[VMS]

Hi Everyone,

I recently purchased an Eagle 642 GPS/sonar combo for the front of the boat. It is brand new and in top shape. I have two issues, though that I am hoping people here can help me out with.

First issue: When running in shallow water or over thicker weeds, the depthfinder portion loses signal and the display stops reading. I have tried numerous things like changing ping speed, chart speed, sensitivity, etc. and nothing seems to make it work. Very frustrating and if it is a bad transducer, easy enough to change..just wondering if it is a setting, though.

Second thing: When calibrating the GPS unit to read and match up to the map, it allows you to adjust it but mine will not. It is not off by much, and it could be more of the map chip than the unit itself, but if my instinct is telling me the right thing, the calibration allows those to match up better. I follow the on-screen instructions to adjust, but it doesn't adjust to the new position. So..any thoughts there?

Thanks to all in advance...

Steve

[fishnutbob]

I have a 27c color just put a new ducer in reads great now. Lowrance had bad ducers.

You can try a few things set your unit up for shallow water setting run your ping at 75 chart speed 100%

Also check for new updates. I would bet your ducer is BAD.

Good Luck

[VMS]

Is there a setting for a 642 with a 200khz ducer and if so, what is it under on the set-up?

Thanks.

[REW]

VMS,
I doubt very much that the gps is your location issue.
To check, use the gps for a land location.
I assume that there is a built in land map as well as the marine map.

Just go to an intersection on a road and stop for 30 minutes. Take a look at the screen of the gps and see if it continues to mark the intersection correctly.

My guess is that it will be right on.

Be sure that you are using Datum wgs84. WGS84 is the defacto standard for most of the land maps on the us continent.

Be sure that you have a ping rate set at 100%, and use the gain in manual and set to the correct level for the waters being traveled.

I like to go to a depth of about 20-30 feet - stop and have the boat stationary. Then, use a 1/16th oz jig and slowly lower it over the side of the boat along side of the depth finder transducer. Continue to monitor the screen and continue to adjust the gain, as the jig is lowered to be able to see the falling jig. When, you get to the bottom, you should be able to raise your 1/16th jig off a hard bottom and easily see it.

Note the gain setting and use this number as a reference for the future.

Also, for best operation, it is normally necessary to have the front of the transducer 1/8th to 1/2 inch below the edge of the transom. Then, tilt the transducer just a bit, so that the back of the transducer is a touch (like about 1/16th to 1/8th of an inch lower than the front of the transducer.

By having the back of the transducer a bit lower than the front of the transducer you will have smooth, water flow that is free of bubbles flowing over the transducer giving you a good bottom reading at all speeds.

When mounting the transducer, be sure to site along the transducer on the bottom of the boat and make sure that it is not mounted behind strakes, stakes, chines, or other objects which would give disturbed water flow over the transducer.
Also, especially for riveted boats, be sure to have the front of the transducer low enough to be in smooth water. A riveted boat normally needs about 1/2 inch more depth than a non riveted boat for smooth water flow and readings.

Good luck
REW

[VMS]

This is on a trolling motor up front so clean water is no issue...

I will definitely do the jig use and adjust from there. Just find it odd that the transducer will not read through weeds....

Please keep the suggestions coming, though....it is greatly appreciated!!

Steve

[yarcraft91]

Steve:

I had the same issue on my LMS334i whenever I was in water less than 13' deep with thick weeds- the sonar screen would freeze and the digital display would flash a nonsense depth number. Three different new transducers (two different brands) did not solve the problem. I swapped the LMS334 to Lowrance for an LMS527.

The Eagle 642 has software of the same era as the Lowrance LMS330 series of sonar/GPS units. The last update to that software was December, 2007. In 2009, Lowrance finally released a software version to solve the problem of poor (complete lack of?) sonar performance in shallow weeds. The 2009 release applied to the LMS520 series, but not the older LMS330 series. Eagle has not released any new software since Dec. 2007, so your sonar probably has a software issue that isn't going to be fixed. I know that's not what you wanted to hear, but that's how I understand things.

[VMS]

Hi everyone,

If it is a software issue, and no updates will be coming out, then I guess I look at that as a situation where a different model is in order. I don't like the issue of having to replace the unit, but if that is what it takes, then that is what will have to happen...

Oh well... :-) no sense in being mad, but at least I know what the issue is...

Thanks for that little tidbit of info!!

Steve

[yarcraft91]

That 642 will probably work just fine in deeper, clean water. I didn't know my LMS334 had a sonar issue until I demoted it from my Great Lakes boat to my weedy-inland-lake boat.