I recently bought a boat that came with a Garmin 320C fishfinder that works really poorly. I know that it is not a high end machine but It should work better than it does. It has a dual HZ transducer but it has absolutely no reading at all when I isolate it to 50 hz, whaen I isolate to 200 hz i have to turn the gain to 100% and i begin to get a weak bottom signal. I have a good idea that it is a bad transducer but if i have to buy a new transducer than i will replace it. However if it is not I think i will buy a Furuno 620 instead. What i would like help with is if someone else has a similiar Garmin around Niceville I would like to plug it into their boat and confirm that it is the transducer and not the unit itself that it is bad. I would just replace the transducer but i do not want to buy one that fits the Garmin and if it does not help now i have to buy a different one that will fit the new Furuno.