Troubleshooting depthfinder Questions

[MikeP]

Yesterday, in St Michael's harbor, the primary depthfinder quit finding.

System is a pair of Networked 3010Cs, a Garmin GSD 21 sounder box, and a Garmin (Airmar) through-hull transducer. System worked normally at the slip and on ride down to St Michaels. After a few minutes maneuvering to anchor, depth indication on both 3010s began randomly flashing depths from 1.4ft to 8.7 feet and continued flashing from that point onward and continues to do it now.

I pulled/cleaned all the plug connections which made no difference.

I hate throwing parts at a problem so I want to isolate whatever has failed. The readout on the 3010s at startup, which checks for available components on the network show that that the GSD 21 is functioning normally. This leads me toward the transducer itself as the problem. Is there a way to determine if a transducer is functioning - any sort of multimeter resistance readout or any other check that would be useful?

When I installed the system back in '05, I recall that the transducer could - in theory at least - be pulled from inside the boat. I have never done that and I seem to remember seeing that there was some sort of a little flapper valve on the ducer tube that was supposed to close and stop - or at least limit - the amount of water coming in. I can't find the instructions for the unit either here on the boat or online. Anybody pulled one like that with the boat in the water?

Suggestions are welcome!

 

[Vincentc]

Mike,
I have a Garmin system and have pulled the paddle wheel part of the transducer in water, no problem. There is a flapper valve and should be a dummy plug to put in its place, while you clean the paddle wheel.

But that will not allow you to remove the transducer.

How cold is the water there. I would go overboard and take fish eye view of the transducer checking for barnacles or debris. I have no knowledge if that could cause you problem, but it's cheaper and quicker than a haul out. I recall you good advice to me regarding a few barnacles causing shaft vibration.

Good luck.

 

[MikeP]

Ahh - thanks...yes, I remember now - it's the paddle wheel portion that was removable, not the transducer itself...

I was planning to dive the boat in St Michaels to clean the shafts/props anyway but the wind came up and the boat was moving around so much at anchor that I decided not to do it. It's too hard to "hang on" in those conditions. So I guess I'll get under it in the marina to do that and also see if there's any build up on the ducer that might be causing the problem.

Luckily, the in-hull transducer that runs the Raymarine ST40 back-up depth finder is working just fine and it has to shoot through the hull AND whatever stuff is on the bottom. I guess there could be some particular thing right on the Garmin transducer causing the problem - though I can't think what that might be. It's too overcast to dive the boat today in the slip; there's precious little visibility in the CHes Bay anyway and with a gloomy day and being under roof, the usual 18" of visibility becomes even less!

 

[Bob Bradley]

I have a similar problem with my Raymarine sounder. When it occcurs, I turn off the breaker that supplies power to the entire system, then turn it back on. That usually clears it up. Simply turning the unit off then back on with the power still connected does not help.

Hopefully I corrected the problem permanently yesterday via the installation of a Simrad NSE12 fish pack system.

 

[MikeP]

Well - here's something that makes it more annoying...as of 20 minutes ago it's working just fine. I didn't do anything to it this morning that was different than when it was not working the past 2 days. It's been turned on/off several times since it started acting up which did nothing (though I haven't turned off the power to the circuits involved). I don't much believe that things fix themselves so I would not trust it until/unless I find some obvious explanation - like a tree branch hung up on the fairing block or whatever that just happened to fall off this morning while sitting here in the slip.

 

[rsmith]

Transducers do go bad in time. Its kinda like getting cataracs, you dont know your going blind till you cant see.

 

[MikeP]

Ended up diving the boat yesterday - nothing on the underside of the transducer. Depth info is working fine now and has been since yesterday morning so I have no clue as to why it wasn't working for two days.

 

[MikeP]

Update from a year ago...

Depth not working again - same symptoms as before. Based on the troubleshooting I've done, it appears that the transducer itself has failed - all other related electronic components check out as operating normally. So it looks like in order to replace the bad 'ducer the boat will have to come out of the water. Not sure I'm going to bother with it. My single ST40 with its in-hull transducer works fine and I could just add a Raytheon Seatalk connector and a second ST40 and have depth at both stations. A lot easier than hauling the boat to remove the old ducer, install a new one and chase the wire to the Garmin GSD 21. I don't care anything about the fish finder/bottom profile anyway, depth is all I need.

We've been thinking of hauling the boat for bottom painting next year and that would be a good time to replace the through hull transducer...or not. Would have liked to believe that a new transducer, installed in '05 would last longer than 6 years; The tranducers for the old Datamarine depth finders were working just fine, 25 years after installation, when I removed them and "upgraded" to modern equipment.

 

[gbharrington]

Mike,
Any chance that you still have the Datamarine transducers?? I could use one.

 

[Beckytek]

Sometimes very muddy water will cause that. That used to happen to me at a certain location everytime when I was in Barnegat bay.
I was just in St Michaels last week. I go in the back way from Oxford and dinghy in. If you stop by Oxford my slip is at Campbells at Jack's point. I would be happy to meet you. Ron

 

[MikeP]

Greg, - sorry, no. I tossed the datamarine transducers when I replaced those units.

Ron - thanks for the offer! We had been planning to go to Oxford this week but ended up with less time than originally planned so went to St Michaels instead. Maybe we'll get a chance to visit Oxford next season!

 

[Trojan]

I would brush off the transducer with a wire brush before I would write it off. Check the cables going to it. Something does not sound right. Check for broken wires or chaft cables. Put an Ohm meter across the transducer and move the cables around See what the Ohmage reads. It should be steady. It keeps sounding like a bad connection.


Bill

 

[MikeP]

Bill - I agree re connection but I have cleaned/recleaned all connections in the various devices (two 3010Cs, the GSD21 sounder module and the Garmin network interconnect module. Last year I cleaned the transducer face on the hull. It wasn't obstructed and the cleaning made no difference. The flashing green lights on the GDS and network module indicate (per Garmin) that they are operating correctly, the 3010Cs shows the same - everything operating normally but the depth reading is flashing which, per Garmin, indicates that no depth info is being received from the transducer.

Hmm...it just occurred to me that I didn't check/clean the screw-terminal connections for the Garmin 3010s - I cleaned the plug-in cable connectors that interface the various modules. I don't think the connections at the screw terminals have any affect on the depth readings/transmission but maybe...

I'll pull the overhead console apart (again! ) and check those connections.

 

[Pascal]

Mike

If you had a connection issue between the module and the displays, you d have a sounds module error, not a signal loss

Two years ago Angela had a similar issue with the same Garmins. If I recall correctly, I pulled my Garmin 2010 and we connected it to make sure it wasn't her display acting up

In addition to aging transducer, check for chaffing or interference. Earlier this year I helped a neighbor troubleshoot signal loss on his 60 marquis with a Ray system. Turned out the MarineCrap tech had moved the tranducer cable and placed it on a air con blower!

 

[MikeP]

Thanks Bill!

If you had not mentioned connections again, I would not have thought about those terminal block screw connections. Even at that I was thinking the connections were just power, not data - I installed the system years ago so I had pretty much forgotten. But the GSD sounder module output goes to those terminals, as well as the GPS antenna and other items.

I discovered 3 loose connections (screw/ring terminals) and yes, one of the loose ones was the sounder module. I loosened the rest, shot them all with De-oxit, wiggled them around and re-tightened them. Depth is now reading just fine on both 3010s - no flashing and tracking perfectly with the back-up Raymarine ST40 depth finder. I found it interesting that the connections had loosened over time and it once again calls attention to the need to periodically check all such connections. I do it routinely with big cables - batt, etc but had not been doing so with instrument terminals/connections. So it's another reminder to check such things - I know I SHOULD do this periodically but I obviously left it too long in this case.

Again, thanks for reiterating that it sounded like connections...I had convinced myself that I had checked the relevant connections.

 

[MikeP]

Oh well, it worked perfectly for 4 days; now back to not working, same symptoms