possessed stereo

[serisdaddy]

ok now if anyone can explain this and help me figure this out you are good....no you are awsomed. I just bought a 1988 thunder craft and it has some problems, but the one I am most baffled by is this---> when I turn the radio on the face lights up and seems to work fine but without sound. So I checked the speaker wires and all is hooked up right so I go ahead and push the tilt button and it doesnt work so I use the trim button and down my outboard goes. Upon completion of its descent while the trim button is still pressed on goes the radio loud and clear. Let go of the button and off it goes. I rewired the whole thing and still it will only work with the trim button pressed...but NO wires are going to or near the button or wiring harness?????????:| I worked on it for 3 hours yesterday and cannot figure this out........PLEASE HELP ME

 

[vipzach]

Re: possessed stereo

Welcome to iboats!

Where are your power and ground coming from? There has to be something that is common between the two!

 

[MrBigStuff]

Re: possessed stereo

Does your trim have a dash indicator for trim level? If so, then you have a potentiometer that "reads" the trim height. I wonder if you have some freakish ground path for the radio that goes through this sensor. As the resistance goes down with motor height, the stereo voltage rises to the point it operates properly. SWAG for sure but the only thing I could envision from this perspective.

I'd run all new supply and ground wires to the radio and see if the problem is cured. If so, you've got some other wiring issues to address as well.

Good luck!

 

[serisdaddy]

Re: possessed stereo

Yes there is a trim guage but I have already ran new wires not only from the boat battery but also from my cars battery. All new speaker wires as well. I know I have wiring issues Im just hoping that they arent too bad. Is there a website I could go to to get the wiring scheme for this boat that you know of?
thanks

 

[Boatin Bob]

Re: possessed stereo

Couple of things to check, the OMC Cobra has a couple of big 50amp glass fuses on top of the engine near the back, they are in individual black rubber round inline fuse holders, one is just for tilt/trim and the other pretty much does everything else for the engine, pull these apart and check for corrosion, clean the ends and put back together, sometimes the corrsion can act like high resistance short and cause weird symptoms, other thing to check is the big round barrel plug which has all the connections for the main wiring harness, take it apart and put together a few times, could be a bad connection in there. Is this a newer style stereo with 2 power leads, one for memory and one for power?

 

[b00tstrap]

Re: possessed stereo

Yes there is a trim guage but I have already ran new wires not only from the boat battery but also from my cars battery. All new speaker wires as well. I know I have wiring issues Im just hoping that they arent too bad. Is there a website I could go to to get the wiring scheme for this boat that you know of?
thanks

Do you have more than one battery in the boat? Maybe pressing the trim switch is also feeding 12v from one circuit into another bringing up the voltage so the radio starts to work?

Is it a "high power" radio ie. the speakers do NOT use a common ground?

Perhaps when you raise the drive, the wire harness is being moved and a speaker wire is shorting out against the speaker basket or something else?

 

[serisdaddy]

Re: possessed stereo

as to boatin bob...yes there are two power wires and I will definately check those fuses thank you Ill keep you informed
as to b00tstrap... there is only one battery and there isnt a common ground for the speakers, each has its own.
Now as for what happened earlier today while fiddleing with it...if I turn the radio all the way up i can hear the music very low and if I puch the trim button really quick and let go the speakers blare and continue to do so...sometimes I can turn it down and it will continue for afew other times it would turn off but always cuts in and out almost as if shorting out...I think the fuse thing may work but we'll see tomarrow
thanks guys

 

[b00tstrap]

Re: possessed stereo

I'm thinking your speakers are shot ( at least one). The symptoms you described mimick what happens to a high power head unit when a speaker(s) is shorting out. If you can remove the speaker cover (grille) push in gently on the cone to see how freely it moves. If it feels "crunchy" the motor (of the speaker) is corroded. By moving the drive unit of your boat, the vibration may make the speakers play and stop. In car audio land, we see this in door speakers quite frequently.

You can also try disconnecting the speakers one by one until the radio plays (unless they are all bad).

 

[Gone]

Re: possessed stereo

Just for giggles, run a + and - from the battery, Connect the - to the black wire of the radio and + to the two power wires (I assume that they're red and yellow, though they may be red and purple if it's not a name brand).

This will tell you if the radio is OK or there is a weird wiring problem.

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