I had a Humminbird 798 in the dash everything worked fine, Replaced it with a Helix 7 mega si, now the speed read will only work up to about40 mph? I have a mega si ducer, and a reg sonar 2d ducer with a y cable on the helix. The 798 had the si ducer which I removed with it, and also had the same sonar 2b ducer that was left on to use with the Helix Mega. Do I need a different Y cable to use with mega.....? With the 798 speed would pick up off the 2d ducer automatically.
Last edited by STROKER10; 06-15-2019 at 01:43 PM.
You have a mismatched 2D transducer.
The MEGA unit uses HW CHIRP.
You have a 83/200 kHz transducer.
If you want to use the current 2D transducer, you change the unit setting to match it and loose the MEGA frequency.
I have the 2d ducer and tge mega ducer the unit came with. On my 798 it would read the speed off the 2d when i was running automatically, didn't have to switch anything on the unit.
You need a different transducer than the 2D you have if you want the Helix to work properly.Originally Posted by STROKER10
Re-read the first paragraph in post #2.
Wayne Purdum
Charlottesville, Va.
Helix 12 CHIRP MEGA+ SI G3N/G4N, Helix 15 CHIRP MEGA SI+ GPS G4N
SOLIX 12 SI/G3, Helix 8 CHIRP MEGA SI+ G4N, Ultrex 80/LINK, MEGA360,
MEGA LIVE, LIVE TL
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