Topic: 798ci si hd not reading depth

[bthom]

I've had this unit for 3 years.  Depth and 2d along with everything else was fine until this summer.  Started with depth getting frozen at 3 or 4 ft. and unable to graph in 2d.  Eventually (usually once sitting still or at 1 to 2mph trolling) it would come back to life and work normally.  Started happening more frequently, typically when on plane.  Started going back and forth between providing depth and not.  Seemed like a loose cable or something.  Most recently, would only provide depth and graph in 2d for approximately 15 minutes out of 3 hours on the water?  Does anyone have a suggestion as to what is wrong?  I bought the boat (glass) pre-rigged and and couldn't tell you what cables I have, etc. etc.  My initial though is my transducer is failing but I have limited experience and nothing to base that on??  Help please.

[ITGEEK]

I would check the obvious first:
1) Make sure all connections are tight.  The ones in the back of the unit, the ones to
    the battery, and make sure the transducer is tight.
2) Charge up your battery and have it load tested.
3) Make sure your transducer is more or less level with the water, with the
    boat in the water, and fully loaded.
4) Look at the self test of your unit to see if there are any obvious problems.
5) Upgrade your unit software to the newest available.
Good Luck.

[bthom]

Pulled the unit out of the dash last night and dropped in the water to test.  Prior to doing that uploaded latest software.  Plugged in things one at a time, left Ethernet cable off.  Everything seemed to be working.  Not sure if the software did it or had a loose cable.  The one remaining issue I have right now is the top 7.5 ft. of the water column in 2d sonar isn't graphing.  It's pretty much solid yellow, orange, and red.  If I reduce the surface clutter down to 1 then I get it to be just the top 5 ft. not graphing.  Any suggestions on what I need to adjust to fix that?

I have a 788 up front with the transducer in my Minnkota I-pilot.  How do I get rid of interference when the motor is running?  Looks great if the trolling motor isn't running.  When it's running though it's useless.

Appreciate the help so far.

[ITGEEK]

I would check your depth offset setting (under your set-up menu).
You always want it to be a positive number.
With the boat in the water, and fully loaded, it should be set to
the distance from the surface, to the bottom of your transducer.
When set correctly, your displayed depth will be the depth of the water you are in, and
not the depth of the water under your transducer.

When you have your surface clutter set to 1, that is the most filtering.
10 is the least filtering, and you should see more on the 10 setting.

Trolling motor interference is always a MAJOR problem/complaint.
What I would do is to first, is to get a small dedicated battery, and ONLY hook your
sonar to it.

If you still have interference, there are plenty of posts on this forum that show remedies.
Good Luck

[rnvinc]

Does the 798 have an additional "shoot thru" Dual Beam xducer attached with the AS SIDB Y cable ...??

Rickie

[rnvinc]

Here is info on tracking down interference for the front unit ...

http://www.humminbird.com/Category/Support/FAQ/Trolling-Motor-Interference/

Rickie

[bthom]

Yes, it does have the "Y" cable

[rnvinc]

Yes, it does have the "Y" cable

Disconnect the AS SIDB Y cable and plug the XHS 9 HDSI 180 T directly into the head unit ...(the xducer model number is printed in the cable about 1ft from the connector end) ...

If your depth issue is fixed ... There is a problem with the AS SIDB Y cable, the shoot thru Dual Beam xducer, or the epoxy glueing the Dual Beam to the hull ...

Rickie

[bthom]

After seemingly resolving the issue with this unit it has quit working again.  2 trips out fishing was fine, and then it went haywire again.  The only thing I did the first time was disconnect everything, upload the latest software, and plug it back in and presto.....all good.  Now I'm right back to original problem, opinions?

[rnvinc]

Isolate the units by disconnecting the Ethernet ...

Then try the 788 head unit on the 798 base ...(the 788 will only show 2d but it may indicate if there is an issue in the cables leading to the transom xducers) ...

If the issue is still present ...disconnect the AS SIDB Y cable and plug the shoot thru directly into the 788 to test the shoot thru xducer ...

If the issue goes away try the 798 directly to the shoot thru ...

I'm suspecting a bad AS SIDB Y cable or a faulting shoot thru ...

Rickie