Garmin Sonar Problem

Redfisher16

Recruit
Joined
Jul 23, 2017
Messages
5
Hi. I'm new to this forum and hope I can find answers to questions I have regarding my newest toy. I recently bought a used boat (2015 Hewes) that came equipped with a Garmin GPSmap 741xs. Ever since I bought it I've been experiencing problems on and off with the sonar part of this unit, more often than not recently. It will work for a bit then it appears to lock up with the depth numbers flashing on and off and no bottom line showing as though it's stopped altogether. This usually happens when I'm running on plane, but now it also happens when I'm just drifting in calm water regardless of the depth.

Rarely it will reset itself and start working again, but I usually have to shut it down and reboot the unit. When I do that it will either start working normally again for a short period before locking up and flashing again, or occasionally I lose the bottom line and depth numbers altogether as though there's no signal at all at which time I have no choice but to reboot it again. I've tried checking all my connections, looking for corrosion on my fittings, and making sure my transducer is properly aligned but nothing seems to work.

I've tried calling the Garmin support line several times, but my wait time to talk to an actual person has generally been 30 minutes or longer and I just don't have that kind of time to sit and wait for someone to answer the phone. So I thought I'd throw it out here and see if anyone else has this issue or knows of something else I can try before I bite the bullet and sit on the phone waiting for a support person. At this point I'm all but resolved to thinking I might have to send it back to Garmin for service which is not an appealing idea but it may be my only option. Any ideas? Thanks.
 

MH Hawker

Vice Admiral
Joined
Jul 13, 2011
Messages
5,516
sounds like its losing the reflected signal, make sure its bolted down and level when the boat is in the water
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
WOW, that could be the receiver section, or even the transmitter section not transmitting anything. But either way, It sounds like something internal rather then an outside connections would fix. The number of internal possibilities is a long list. The only outside possibility I would check would be the transducer itself. If that tests good, You need the head unit checked out. JMHO
 

Redfisher16

Recruit
Joined
Jul 23, 2017
Messages
5
The transducer appears to be mounted properly, it's tight and level, so I'm leaning towards an internal problem with the unit itself. I guess I'll just keep trying Garmin support until I can talk to someone and see what they say, but it appears likely that I'll be sending this thing back to them for rehab. Oh well, Break Out Another Thousand...the burden of all boat owners. Thanks.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,370
99.4% sure that it's the transducer failing....

Nothing sonar related to fail in the head unit. All the sonar related processing (send and receive) is done in the transducer. The head unit simply powers the transducer (pulse generator) and processes the returns for display on the screen.

The flashing is the head unit waiting for data to come back from the transducer.

I've never had more than a couple minute wait when contacting Garmin. Always call first thing in morning @ 8 EST
 
Last edited:

Bayou Dave

Lieutenant Commander
Joined
Dec 13, 2012
Messages
1,780
Have you updated the software for the 741xs? Doing that may help the unit recognize the transducer you have.
 

Redfisher16

Recruit
Joined
Jul 23, 2017
Messages
5
Dingbat, I don't know much about how these things work, but what you say makes sense. I'll see if I can get that checked out before looking at the unit. I will try contacting Garmin again and do it early to see if that makes a difference.

DRS4164, no I haven't done that but will ask about it if/when I talk to Garmin support. Could be the problem. Good suggestions all, thanks for the replies.
 

Bayou Dave

Lieutenant Commander
Joined
Dec 13, 2012
Messages
1,780
Do you know what brand and model transducer you have? It may or may not be compatiible with the 741xs. When I bought my 741xs I checked Garmin and got a transducer that was compatible with it. My 741xs came with software ver 6.50 and I updated to the most recent one, 6.60. What difference that made I have no idea.
On a side note, do you keep the plastic cover on your unit while towing? It seems a little loose on the unit and hate to see it fly off wile towing.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,370
Do you know what brand and model transducer you have? It may or may not be compatiible with the 741xs. When I bought my 741xs I checked Garmin and got a transducer that was compatible with it. My 741xs came with software ver 6.50 and I updated to the most recent one, 6.60. What difference that made I have no idea.
Most, if not all manufacturers configure the connectors so you can not plug a incompatiable transducer into a head unit. If the transducer plugs in, it's compatiable.

Changes made from version 6.50 to 6.60:
Added support for 2017 built-in US mapping.
Added the Navaid Labels toggle.
Added magnetic variance updates.
Other performance improvements and bug fixes.
Changes made from version 6.40 to 6.50:
 
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