New Garmin Chartplotter with Old Transducer
Buying a new Garmin chartplotter and save $1,000? Here's my story:
When we bought Meridian it had a fairly new Garmin 740s chartplotter but no transducer was included for reading the depth. We only need depth, not temperature, speed or fish finding. The original 30 year old depth sounders were on their last legs and mounted where they were not easy to see. The boat came with a 20 year old fish-finder which did not work so I tossed it but not the transducer. I had checked with Garmin and Airmar and both said I needed a new transducer for the 740s. Now months later in conversation with others on how Garmin uses the temperature sensor in the transducer to show that is working and if that goes bad you can just tie the + and - on the Garmin side together and it will show that the unit is functional. This evening I recalled the conversation with Airmar where they said that Garmin needed the temperature sensor for the unit to work but didn't say why.
I cut off the old fish-finder and Garmin connectors, searched the web for the pin-outs and wired it up to the old transducer. I now have depth directly on my chartplotter plus the original two units for backup.
So where did the $1,000 come from? A new transducer is $450, plus a haulout plus pulling the old transducer, enlarging the hole and mounting the new transducer. That's an easy Boat Buck.
If you are adding a new unit you may want to try this out prior to buying and replacing an existing transducer. I'm sure it would be the same with other brands as the depthsounder only has two leads + and -.