perplexing new stereo install problem.

[erider81]

hi folks,
I'm having the strangest problem and im all out of ideas so i figure take it to the experts here. I just installed a new Jensen MSR2107 stereo with sony speakers in a 2001 Bayliner capri 160BR with a 90hp Merc. The stereo works excellent as long as the motor is off. soon as i start it the radio goes nuts, the screen has anomolys flickering on it and the sound keeps cutting out or if im listening to mp3s they distort, wont play or just cut out like the radio does. I figured it was just somewhere in my wiring so today i did the following:
removed both ground and power from the connections on the boat and ran it to a seperate jump start battery. Still had same issue.
then i removed the speaker wires from the radio connection thinking one may be running next to a wire causing interference. But the screen still flickered so i assumed the radio was still cutting out, no way to tell for sure since there was no sound at that point.
i made sure every wire was no where near any of the boat wiring and the issue still persisted.
soon as i shut off motor, everything worked fine. the head unit of the radio is installed about 8 to 10 inches below the ignition switch.
I checked voltage in the original connections and all was fine between 12 and 13 volts when motor was running.
Does anyone have any clue as to what my problem could be? it seems to be grabbing some kind of interference from something when the motor is running even though i completely eliminated any connections to the boat itself. the only thing i didnt do was remove the head unit from the dash and try moving it away.

thanks,
Glen

 

[Toxarch]

Re: perplexing new stereo install problem.

Try disconnecting each wire one at a time until the interference stops. That will help you figure out if it's a wiring problem and which wire. You can try pulling the wire and pin from the harness plug. A bit tedious to do, but it keeps all the wires intact. You might remove them all except the power and then put them back in one at a time to make it easier. If that doesn't do it, then you MAYBE could have some kind of induced magnetic field around the stereo. You could try the following to see if you can block the field, but it might not work. Find some brass screen mesh if possible. A small section is all you should need. Wrap it around the stereo and then connect it to the ground wire. It should block any inducted magnetic and radio signals. If you can't find the brass mesh, you can try a steel or aluminum one (cheaper) but it doesn't block RF. It's a long stretch, but if it isn't the wires, maybe this will help.

 

[erider81]

Re: perplexing new stereo install problem.

i think i eliminated actual wiring issue since i had the thing basically down to just power and ground running off a stand alone battery (right next to the unit) and still had issues. the radio unit is a 2 part thing (blackbox) and the cable that runs from the head (controller) to the main unit is rather long is it possible thats acting like an RF antenna? last night while doing all my different tests the radio flash memory wiped itself. it has 1 gig onboard memory for storing mp3 files. i had about 50 songs on it and while trying to play off of that drive it would jump around or do its usual and sometimes it would just say no file. now all it says is no file even with the boat motor off. Does a 2001 90HP merc send out that much RF interference as cause electronics to really screw up? i do not have resistor plugs in the motor, would this cause all this headache?

 

[Silvertip]

Re: perplexing new stereo install problem.

Any ignition system produces electrical noise. I have a 75 HP version of that engine and my stereo is installed in the same manner as yours and there is no interference whatsoever. The large harness that runs from the engine to the control box has the ignition kill switch wires in it. The magneto wire is sitting there open circuit with the engine running and is shorted to ground with the key in the OFF position to kill the engine. You may be picking up interference from that line. It would have a 6 pulse/engine rev signal or 4200 pulses at 700 rpm idle speed. You may also have a bad diode in the rectifier which allows an AC signal on the +12v bus. If the electrical system checks out ok you may need an interference filter in the hot lead to the radio.

 

[lowkee]

Re: perplexing new stereo install problem.

Maybe your regulator from your alternator is burnt? You could also try buying a decent size capacitor and putting it inline with the power wire, that will smooth out any voltage spikes for now, but you should still find the source of the issue (cheap radio or bad voltage regulator)

 

[erider81]

Re: perplexing new stereo install problem.

just wanted to clarify the stand alone battery i had the radio hooked up to was a jumpstarter, it had nothing to do with the boat battery at all. so with that said, is it still possible that its a rectifier problem? the issue is definitly coming over the air so i assume it would be magnetic or RF. does this make sense?

 

[slia67]

Re: perplexing new stereo install problem.

Do you have another stereo you can swap out with your new Jensen? Since you have isolated the boat wiring from the stereo, it only goes to reason that it is probably your new stereo or as you stated the cable connecting the face plate to the "black box" picking up the noise.

But before you do all that try changing out your plugs.

 

[lowkee]

Re: perplexing new stereo install problem.

Hmm, something is definitely amiss if, while completely standalone from the boat wiring and playing mp3 and not radio, it still goes crazy, but only when the boat is running. I don't know what to tell you.. that doesn't seem possible :/

 

[TBarCYa]

Re: perplexing new stereo install problem.

Does the cable that connects the controller to the black box run near any other wires in the boat? Is it possible to hang it over the side away from any other wiring for testing?

 

[erider81]

Re: perplexing new stereo install problem.

Does the cable that connects the controller to the black box run near any other wires in the boat? Is it possible to hang it over the side away from any other wiring for testing?

the cable is about 12 inches from the ignition switch, but tonight i'll unmount the controller box and run the cable away and see what happens.

Im starting to get afraid the FCC is going to come after me for illegal broadcasting. heh.

i have an old car stereo i can prob wire up but im not sure if thats going to be a good test. that will be my step i'll try after changing plugs.

 

[erider81]

Re: perplexing new stereo install problem.

well changing out the plugs to resistors worked. Im amazed that thing had the ability to cause the issues it did just because of spark plugs. Hopefully this tread helps someone else out in the future. thanks everyone for the suggestions and help.

Glen