Anyone with Humminbird Experience...?

[Willy]

Hey all,
I have a used humminbird 535 fish finder I just got working (Thanks Dgax65!!!!).
I'm having a big problem with the transducer (transom mount):

It won't read a proper depth. The temp sender on it works fine, but it always says I'm in anywhere from 100 - 800 feet, with either a flat black bottom, or a bottom reading that looks like a bar graph. The depth usually sits around the 750 range, even in Mission Bay or my swimming pool.
The transducer worked well in the last kayak, mounted as a thru-hull.
I'm trying to use it on my new skiff, as a proper transom mount.

I'm pretty sure Mission Bay isn't 800 feet deep.


Anyone have any experience with this issue?
(Sorry for the awful picture)

Thanks all,

Willy

[ronbo613]

In my experience with Hummingbirds; I've found their connections to be a little problematic. Make sure the connectors are clean and shiny; especially the plug that goes into the finder from the transducer.
Doesn't cost anything to check it out.

[peguinpower]

I had that problem once. It was due to a degraded power connector between the battery and the power chords.

Get a digital volt meter.

Take a reading from the battery terminals AT THE BATTERY. It should read between 11 and 14 volts.

Then take a reading AT THE GOLD TERMINALS ON THE HUMMINBIRD BASE.

It should read the same. If the reading is less, or jumps around, there is corrosion somewhere along the power lines feeding low or noisy power to your FF. Either the connector. or the fuse, or the butt joints, or the wire has the dreaded black wire disease. Fix appropriately.

/bing

[Willy]

Great advice gents.

I was lucky enough to have married an electrical engineer, who has the ability and knowledge to do these recommended tests.
Not that I can't, but it sure helps to have her input...

Also luckly Dgax65, Doug, gave me a nice power cable in great condition which allowed me to get this thing working at all.

So Bing, you're right on, there is a major factor to the power cable, and it has indeed been replaced, allowing the FF to work at all.

And Ronbo, you're right on too, the unit didn't work properly until the connectors were completely free of corrosion (we soaked them in vinegar for almost a week to make 'em, shine again).

But I'm still getting the funky signal, at which point the wife suggested I ask my friends in 'the fishing club' as she calls BWE.

Thanks for the input guys,

Willy

[dgax65]

If the temp reading is correct and stable, but the depth reading is spotty, it might be a single bad pin or conductor. I'm not sure but I think there is a very small gauge coax that carries the signal data from the transducer. If the cable gets kinked it can break or damage the small gauge internal conductors. Recheck the pins and sockets. Sometimes even a little corrosion can cause problems. The signal voltages are pretty small. I always put some dielectric grease around the connector to keep water out. Sometimes I would accidentally get a blob on the connector pins and I would get some very erratic readings. Try cleaning the contacts again with alcohol or contact cleaner. If you have some hard corrosion or pitting you can sometimes clean it up with a dental pick. Just be careful; those pins are fragile.

You might check around to see if somebody has a compatible transducer that you could plug into your head unit for troubleshooting. That would give you a good idea if it is the transducer cable or the head unit.

Check the Humminbird site for compatibility: http://store.humminbird.com/products/314027/XNT_9_20_T

[ronbo613]

I usually use a paper clip to clean out the female terminals on my fishfinder connection cable. There is usually one terminal that seems to be more corroded than the others.

[peguinpower]

btw, humminbird has a flat rate to fix stuff. call it in, theyll fix it for the flat rate, and you may just get a reconditioned unit.

/bing

[SoCalSal]

I have seen this before with magnetic resonance, if the ducer is too close to the unit they can interfere with each other. also try coiling the extra cord in a coil and ziptie (usually instr with unit) or in a fig 8 pattern. Is it a thru hull or in the water, I forget, thru hull can cause reading errors too if gaps exist between ducer and yak.