788/798 problems

[capt charlie's charters]

2012 a good friend of mine, who knows his stuff did the installation of my new 788 on the bow to link up with my 2011 798 on the consol.  everything worked fine, including the interlink.  first month of the 2013 season all was well then I started noticing the following.

788....realizing disturbance from the Minn Kota, even reducing the sensitivity failed to eliminate and suddenly the two units weren't talking.

798....various time when starting the Merc the screen would go vertical lines and lock up, the only way to turn it off was to turn off the main power switch for the boat.  I could then turn the unit back on after the Merc was started.

back to my friend and even he was unable to determine the reasons why....anyone else run into these problems ? 

capt charlie

[Slipkey]

If starting the engine is causing the unit to be affected, there is something wrong in the way the power switch was wired up or in your fuse block or you've got a problem with grounding on the main motor.  Same with the trolling motor.    Don't continue with the status quo or you can ruin one or both of units.

First thing to check is that both the TM and the main engine are wired directly to the battery and the units are wired in to an accessory fuse block. Depending on your boat, the fuse block may or may not be wired to the main battery.  If it's wired to the main battery, directly, make sure the board, itself, has an inline fuse.   Second, make sure the recommended inline fuses are in place and are the proper size. The latter is *very* important.  I used to be lazy about keeping the inline fuses when I was wiring in to a fuse block, until I got bit by it and fried a unit.

The wiring diagrams for all of the marine electronics MFR's all show the unit connected directly to the battery.  If your motor is over 50 HP, though, you're going to have electrical noise/interference if you connect a modern GPS/Sonar direct to the battery.  I, personally, run all of my direct battery connections, except the main motor and trolling motor, off of a bus bar attached with 6 gauge wire to the main battery. That's more for preference, as the fuse blocks insulate well enough from noise, if they are decent quality.

If your accessory fuse block is protected, a "quick-and-dirty" fix might be to install an in-line engine noise suppressor between the battery and the fuse block. Here's an example:

http://www.ebay.com/itm/40-AMP-IN-LINE-ENGINE-NOISE-SUPPRESSOR-FILTER-12v-16v-/250734037372

Hope that helps,
Jon

[Redbone]

I not going to be much help on this... but are your batteries getting old? Maybe getting drained below 12v when the engine is cranking? Just a guess.

[Waterfoul]

Yup, try a new battery (borrow one?) and see if it helps.

Also, have you been keeping up on all the Humminbird updates for you units?

[Rangerman]

There is a cure for RF snow from trolling motor. I cussed and tried every Snake Oil Cure from MK/Humminbird for 18 months. Got in touch with tech support at MK and they send me a Ferrite Ring at no charge. You loop the transducer cable thru is 6 or more times and it was cured. I had installed new battery, direct wiring PC 11 HB Choke wire, ext choke and still there. I even purchased a New MK 101 Fourtrex to try and get rid of the rf noise. I was running the filter on High 3 on the HB 788 and getting snow when trolling motor powered up. After the Ferrite Ring, no snow zero!! Dropped noise filter a step at a time and still no snow. Now set on RF filter off and works like a champ. Good luck. Only question is why did it take 18 months to get this figured out? Alot of service center not aware of fix. The Ring was free from MK and it sure did the job.

[capt charlie's charters]

thanks everyone, I'll contact the help desk next, just was hoping to see if anyone else had the same problems.

NOTE....everything worked in the 2012 season after installing.
New batteries start of 2013 season.
Transducer shield/saver installed 2011.
We/Seth added a rubber pad between the Kota and the Shield/saver to see if that would help to eliminate the interference that hadn't occurred back in 2012.
Seth also checked to make sure everything was still grounded properly from the 2012 installation.

Merry Christmas and Happy New Year
capt charlie

[capt charlie's charters]

guess I should've added, boats a Triton 196 bought new in 2002 along with the Merc 175 EFI, originally cam came with Garmin electronics before switching over to the HummnBirds 2012.

charlie