Boat stereo issues - paging experts

[dhcomp]

Ok, so i have a 2008 Malibu Response LXI.

JBL /Prospec electronics developed a new "black box" headunit that hides away, and is controlled by remotes.

http://prospecelectronics.com/JBL%20MBB319.htm

Neat idea, doesn't work so hot.

Right now, i am having a hissing noise when there is no source running, but the hiss continues when music is playing (just not as noticeable).

Here is the post i posted on a malibu site, anyone have any suggestions?

Thanks in advance!

Ok, So i have an 08 RLXI with sound pack 1.

Standard JBL black box, works ok besides the ipod controller not functioning with my ipod.

Haven't used the stereo (or teh boat) much so far.

Noticed today that when the stereo is in USB, or AUX mode, there is a pretty good hissing when there isn't a signal playing.
Hiss is also noticeable when music is playing, just not as much.

Hiss does not vary with volume, but when volume is changed from 1 to 0, Hiss significantly reduces.

First thing i thought might solve it is regrounding the head unit.

I cut the black wire coming out of the JBL harness, and checked continuity between the side plugged into the harness and the battery. Resistance was almost negligible, less than my cheap Multimeter would even pick up. So i am using the correct wire, and the factory ground wire has a good connection.

Hook Black box ground wire directly to battery anyways, hiss doesn't change.

I also disconeected the AUX cables at the black box, in case something was interfering with those.....and nothing changed.

Just for the heck of it, i left the black wire (ground wire in harness) for the black box disconnected, turned on the key, and the unit still powers up and works.

WTF. There is no reason the unit should power up without a ground. This tells me that either i cut the wrong wire, or its grounding somewhere else. I verified the continuity to the battery negative, and also verified on teh wiring chart.

If you can't tell already, i have expereince in car stereo's. This is the 2nd boat stereo i have worked with, but have done 3 or 4 amp installs, and a couple full installs on automotive stuff.

So.....where is this unit grounding through? I'm guessing whatever funky ground is causing it to still function without the ground wire is also causing my hiss.......but if you think otherwise, let me know!

Any guesses?

Thanks guys!

 

[lectric80]

I would try a different stereo, if there is no hiss it is most likely an issue with the black box unit. The ground issue makes me believe that it is the black box, but I don't have the wiring diagram for the unit. In a boat there is no way that it should be powering up without the ground, unless it is grounding out somewhere else, which means that it is defective.

 

[Leper]

The radio may be grounding through the chassis. As far as the hissing, is there anything else running on the boat when it is happening? the noise may be caused by another electrical device. IIWY I would hook the radio up to a seperate battery and see if the noise continues. If so, I would say the radio is defective.

 

[dhcomp]

Its hard to just hook up another stereo to test it. Its all factory wired....and i had to jump through hoops to just cut teh ground wire. Its also probably under warranty, so i probably shouldn't be messing with any of it.

The complicated part is that the controls are not only wired to that remote shown, but also integrated into this new crazy digital malibu dash. I'm guessing it is grounding out through one of these remote connections, as there isn't any way for teh chassis of the unit to ground out through teh boat.

Maybe i'll get out a crapload of aligator clips, and see if i can hookup another deck to the headunit harness. I'll report back, thanks for the help guys!

 

[dhcomp]

Ok, so i ran a dedicated ground, and it didn't help. I figured out it is grounding through one of the remotes, but w/o that hooked up there is still noise.

A different head unit has no hissing.

Time for me to get them to warranty the head unit i guess....

 

[Leper]

Sounds like you got it under control.