788 issues

I have a fairly new hb 788 that I seem to be having an issue with. While fishing a brush pile no matter what the depth is and marked with a bouy at times the pile disappears. Its not like Im not on the pile I am almost positive some of these are large piles and I stay positioned with the marker pretty good. Then sometimes magically the chart blows up with structure again. We even hung up in the brush while the sonar showed nothing. I have the terrova with us2, use 20 and 60 degree beam back and forth to see if it has something to do with it but I have no clue. Any help would be appreciated.

Is this the 788ci HD Combo...??
20 degree cone angle 200kHz
60 degree cone angle 83kHz

Depending on the depth of water fishing... Even the 60 degree beam doesn't cover a very large area of the bottom...and because brush is usually sticking up above the bottom... The branches would be in an even narrower part of the cone shape beam...

Sensitivity settings in the unit could also be set too low to pick up the smaller outer limbs... Creating an even smaller area of "echos" reflected by the larger branches....

This is where the "Switchfire" feature of the HB units can be utilized....

Turn on "Switchfire" Max Mode and then adjust the manual sensitivity down to an acceptable level of extra "clutter" on the screen....

This will allow the unit to pick up and show the smaller limbs of the brushpile ...in effect making the entire brushpile echo to be larger...

I use "Switchfire Max Mode" in water 10 ft or greater( this gives enough screen real estate to separate the clutter from the surface and still differentiate the brush from the clutter)
I use "Switchfire Clear Mode" in water less than 10ft ( shallower water makes it difficult to differentiate between the clutter and the brush)...

Rickie

Rickie
I fish with Puck alot of the time when he goes to the lake and this unit acts pretty strange. Same stuff I have no trouble staying on with my old X-75 will just flat dissappear on his 788 even though I know we're sitting on top of it. Not that big of an issue when we're fishing spots I know and have good marks on, but still frustrating. It is an issue when marking new spots and trying to decide if we're really on them or not. I don't know that much about hummingbird 2d, we'll have to see what mode his unit is set to, we're normally deeper than 10ft so from what you said above Switchfire Max is probably where it needs to be.
Austin

The "Switchfire" Max Mode is really good for picking up the smaller (hard to echo off of) branches...

I would recommend:
Set the unit to 83/200 (to get both beams working at the same time)...
Turn on "Switchfire" Max Mode...

Adjust the sensitivity until the clutter clears up enough to have some clear screen between the top of the brush and the band of "surface clutter"...

Also make sure fhe xducer is pointing straight down and not at an angle shooting thru the water...

Rickie

Here is the HB 2d ...

http://www.crappie.com/crappie/attac...enshots-1-.jpg

Rickie

i set sensitivity with a 1/16 jig lowering it and adjusting til i saw it and moved it up and down until it shows it good. not sure which mode it is in but it shows really good images then just stops showing them in same location as it was showing them previously. i have set it on 20/60 split screen to see whats outside the 20 cone with the 60 and work toward finding it on the 20. it is a hd combo i knew some issues have been had with the us2 transducer but i havent found a consistency with when it does this.

It seems that you have the unit hooked up to the US2...??

Have you tried the stock transducer...??

Rickie

i haven't tried the factory transducer wanted to use that as a last resort. with the terrova it seems that it would be a pain to run the cable to the transducer down the shaft and i hate that i pay the extra $ for the us2 feature if i can't use it.

Quote:

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Originally Posted by Puck99

i haven't tried the factory transducer wanted to use that as a last resort. with the terrova it seems that it would be a pain to run the cable to the transducer down the shaft and i hate that i pay the extra $ for the us2 feature if i can't use it.

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I understand wanting to take advantage of the US2...

It may be a good test to try the stock xducer...(maybe in a "temporary" setup where you could swap the xducer connection back and forth to compare)...

This may give some determination of a problem with the US2...or a problem with the head unit..or a problem with the settings in the unit...

Rickie

Something quick to check on the US2 is to make sure that the metal connector from the US2 cable is screwed on tight to the Minn Kota adapter cable that runs to the 788c HD unit.

Other than that the best way to check to see where the problem is to either hook up the stock transducer temporarily to see if it still happens or try testing your 788c HD unit on someone else’s boat that is running a Humminbird (should work with any 200/83kHz DualBeam or Side Imaging model).