HB will give you a free power cord with a choke in it if you call them. The power cord on the 597 doesn't come with the choke on the cord. You can get a Ferrite Choke at Radio Shack that will snap on your transducer cord for 3 bucks, and that works great if ya don't want to wait on the new power cord. Make sure you get the right diameter Ferrite Choke so it will snap on the transducer cord tight. Prolly a medium.