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Sounder display/transducer Problem

Printed From: The Fishing Website
Category: General Forums
Forum Name: Tech Topics
Forum Description: IT - Computers, software, phones, ISP's....
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=123167
Printed Date: 04 Feb 2026 at 9:36am


Topic: Sounder display/transducer Problem
Posted By: tga fisher
Subject: Sounder display/transducer Problem
Date Posted: 30 Jan 2017 at 10:17pm
I have a humminbird 385ci sounder/chartplotter installed in my kayak and it worked perfectly for years but now I am having a problem with the display and depth reading.

I have taken a lot of care with the unit.

Very strangely i get a reading every 4 seconds so the screen does no display a line for the bottom but a dashed line which is mostly dash Smile

I have very carefully checked the battery connections and fuse connection. I have my doubts that it's a connection problem and I am wondering if it could be a transducer problem. Has anyone else had this issue?

Any suggestions/help appreciated.


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Sorry - out of office - GONE FISHING



Replies:
Posted By: MacSkipper
Date Posted: 31 Jan 2017 at 6:43am
Have you had a look at connector from transducer into fish finder is it corroded?  Is battery voltage marginal a battery typically lasts 3 - 4 years  (check across battery with finder on using multimeter) should be 12V or so under load certainly more than 11.5V (does finder display battery voltage?  Some do or it can be turned on) or can you try hooking another battery up temporarily?  Does finder have a simulated mode (check manual) - if doing in this could be a display issue, if ok could be faulty transducer - would have to try another to rule out.

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Good fishing trip nothing breaks, great trip catch fish.


Posted By: tga fisher
Date Posted: 31 Jan 2017 at 9:30am
Hi MacSkipper. Yes unit does display battery voltage and it was 12.0V. Battery is probably 7 or 8 years old with not a lot of use so I may look at getting a new one anyway.

Interestingly the sounder pins are clean and bright but one pin from the power supply is dull but i have tried to carefully clean it. Is there something I can spray on this pin. I will try the unit in simulation mode to check the display. Is it necessary to get the kayak on the water when doing this test?


Posted By: MacSkipper
Date Posted: 31 Jan 2017 at 2:12pm
Spray connector with WD40 or similar and insert/remove a few times and you will then have a good connection.  Simulation mode is for use on land - usually you turn on pressing or holding various buttons and then gives you a picture so you can play with modes etc.  If reading 12V probably battery is ok - should tolerate down to 10.5 to 11V anyway - will be listed in specifications part of manual.   I assume display plays up straight away not after a time? 

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Good fishing trip nothing breaks, great trip catch fish.


Posted By: tga fisher
Date Posted: 01 Feb 2017 at 9:35pm
Thanks again MacSkipper. Yes the display plays up straight away. I have sprayed the pins on a number of occasions with CRC. I will test the other things you have suggested on the weekend. Cheers


Posted By: Steps
Date Posted: 02 Feb 2017 at 9:25am
Disconnected put a ohm meter between the battery terminal and the conector pin... there should be nil resistance
If there is u may have a bad connection... then need cleaning .. not just a spray of something.
 And after cleaning go to your local marine service dept and see if they will give you a teaspoon of marine grade electrical grease for the connections
 If it is not a connection check the pins each end of the cable.. may have a break inside the cable.

 If dont have a ohm meter.. check the voltage across /on the battery terminal  s and compare at the pins at the other end of the sounder cable.. should be the same.

 Caution spraying solvents into the back of the sounder  and cable pins... apparently some ppl have had issues on some brands....again best is to clean and electrical grease.

The trouble spraying electrics with crc etc is that it doesn't remove corrosion, just sot of moves it to one side... and in car engine type application, ends up having even more dust suspended in surfaces  which then creates all sort of sparking , feed back in circuits and weird stuff... like turn on indicators and a brake light or dash light go on...

 These solvents are quick temp 'side of the road' patch fixes.. not permanent or maintenance stuff

 From your description.. age putting 2 and 2 together, not actually seeing it.. I would guess that maybe something like your screen is dieing..
 Maybe time to look at upgrading...


Posted By: tga fisher
Date Posted: 02 Feb 2017 at 9:44pm
Thanks Steps and MacSkipper. I hooked the unit up this evening and got it going in simulation mode. When i look at the diagnostic screen it is telling me that voltage is 12.6. Also have confirmed that screen is displaying fine in simulation mode so i get the feeling the problem is not the head unit. I'll disassemble the transducer on the weekend and double check the pins and the cable. As i mentioned earlier the cable that terminates with the two pins where it connects to the head unit has one bright pin and one very dull pin. As it is difficult to get at the pins I'm finding them hard to clean. I'll give it another go, and I'll get some  WD40 and see if i can get some marine grease. I think this is the power cable. All three pins are clean and bright on the other cable. 
As the transducer cable is very long i have it coiled up and cable tied under a board that the head unit is mounted on. This did not seem to be a problem early on but i will unravel the cable and check it closely for damage and try the unit on the water when it is uncoiled.
Cheers



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