MEGA SI/DI Transducer Issues

I bought a used 2018 Ranger 621FS and am still figuring out all the toys onboard. There is a through hull, multi-frequency SI/DI transducer on the transom connected to a Helix G3N at the console. When I go to select which transducer to use on the Helix, multiple options come up including MEGA and 455/200 kHz as well as others. If I select the “MEGA” transducer on the unit, my SI and DI shows up as black/blank (not a poor signal or interference or anything). If I select the 455/200 kHz transducer on the unit, SI and DI work but obviously not the MEGA quality. Any way to figure out whether this is a limitation of my current transducer or an issue with my Helix or Helix setting? I made sure that the CHRIP and transducer frequencies line up with no resolution of the problem. Seems weird that MEGA is available as a transducer option in the unit settings if the transducer couldn’t send that info. Appreciate any help with this.

Yes, the transducer options menu will list a bunch of versions, not just the one that you have connected. It can be quite confusing at times trying to figure out which one exactly you have and should select.

Your Helix head unit might be able to handle MEGA, but if the previous owner didn’t upgrade to a MEGA transducer then those frequencies wouldn’t be available to you. With yours operating at the 455 level, it almost sounds like the basic SI transducer. Can you take a picture of the transducer and post it here? The SI (455), HDSI (455/800), and MEGA SI (455/800/1.2M) transducers each look quite different and would be easy to identify for you.

Also, you describe the transducer as “through hull” and “on the transom.” Do you have a single external (transom) transducer? Or, do you have a through-hull standard sonar transducer with a splitter cable for a transom SI transducer? This latter approach is pretty common; another indicator will be the mounting location of the SI transducer on your transom – if it’s mounted above the running water line there is probably a through hull for high-speed sonar operation.
(And they do make through hull SI versions, but these are much less common and there probably wouldn’t be anything on your transom at all.)

Here are pics of the likely SI transducers that might be on your boat. Which one does yours look like?

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   birdsi.jpg
   

2. 

   birdhdsi.jpg
   

3. 

   birdmega.jpg
   

It’s a through hull SI transducer. Sorry for the confusion with the transom verbiage. I talked to Humminbird, and they said the first transducer listed (ie… can’t scroll left any further on the Helix) should be the one to use. That selection is “MEGA”, which doesn’t solve the problem.

OK, so you have one of these?

HRG

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   XPTH-9.jpg
   

KD7633 wrote:

It’s a through hull SI transducer. Sorry for the confusion with the transom verbiage. I talked to Humminbird, and they said the first transducer listed (ie… can’t scroll left any further on the Helix) should be the one to use. That selection is “MEGA”, which doesn’t solve the problem.

Okay, that is good information. Based on your description I still wonder if it’s a non-Mega transducer, and possibly a compact so not even HDSI. Can you take a picture of the transducer and post it here? It should be relatively easy to spot in the bottom of your bilge via the rear access panel in your cockpit. The various models look differently even when it’s a thru-hull, so that could tell us something.

And you may have already done this, but just to rule out setting issues on your unit, try these steps:
1) Reset unit to default settings:
– Push MENU key twice, select the SETUP tab
– Select RESTORE DEFAULTS, exit
2) Set unit to custom operation:
– Select the SETUP tab
– Select USER MODE, select CUSTOM
3) Make sure the default MEGA transducer is selected:
– Select the SONAR tab
– Select first transducer listed (most to left/MEGA transducer)
4) Make sure MEGA SI frequencies are selected:
– Select the SONAR tab
– Select SI CHIRP SONAR FREQUENCY
– Select MEGA or MEGA+
5) Check SI returns. Anything or still blank?

This is the current transducer on the boat:

Appreciate input from everyone. I will try the reset and make sure software is up to date as well.

https://humminbird.johnsonoutdoors.com/accessories/transducers/xpth-9-hw-msi-t-helix-mega-si-di-dual-spectrum-chirp-w-temp-plastic-thru

Make sure to update the software on the trolling motor as well.

Please update us on your results.