Fishmark 320 portable lost sensitivity

[graf703]

I've had the fishmark 320 portable for roughly 4 years with some regular use. I've been overly happy with it so far. It would mark anything and everything in the water column. I've marked 1/8th ounce jigs in 35 ft and watched fish come off the bottom to hit it like a flasher.

My most recent trip to Canada it did very poorly. It would mark the bottom inside of 70 ft of water. But it very rarely marked a fish. If it did it was not as precisely defined as usual.

I was trying to troll for lake trout and sometimes in 60 ft of water i would see what looked like arches well below the bottom in 90 ft of water. I made sure the settings were correct without the fish ID on.

Troubleshooting: Where should I start? the transducer or the head unit?

Thank you!

[graf703]

To complicate things they don't sell a replacement transducer/cable combo. Cabela's has a skimmer I could rewire into the portable pack for $80. I'd rather not take a gamble though

[Gus]

I've got the same unit. Also have been very happy with it's performance until now. This year... mine too seems like it struggles to pick up things accurately. Can hardly see soft bottoms let alone my jig like I could in the past.

[Surface Tension]

More then likely the transducer is bad.

[Gus]

A little follow up.

I pulled all of my cables, power, transducer, etc and cleaned them and reinstalled. There was a little bit of corrosion on the transducer cable plug where it goes into the back of my head unit. I used electronic contact cleaner and a tootbrush.

I also checked the angle of my transducer. It appeared to me like it may have been pushed just 1 notch up. Hard to tell for sure, but I leveled it regardless.

After doing the cleaning and readjustment of the ducer my unit seems to be working perfect again.