radio niose

[-JR-]

Only when my engine is running i get a high pitch background noise in my radio....how do I get rid of it ?
used to have an old car back in the 70s that did this ,thought i but in a condenser somewhere .

 

[fhhuber]

You need resistor plugs. Change for the same number plugs but with an R added usually in the middle. Such as CJ-77 becomes CJR-77 (I made those numbers up...) Sometimes they append the R, then it would change from CJ-77 to CJ-77R

That cures it MOST of the time.

 

[Silvertip]

Here are some NGK resistor plug designations (not necessarily for your engine however):
BCPR7ES, PFR7H - 10, BCPR6E.
If your boat is powered by an I/O, then the noise may be caused by the alternator. In that case a noise suppressor can be installed in the positive lead to the radio. Ignition noise is more like a lower frequency "popping" noise.

 

[bruceb58]

Sounds like an alternator whine. Pull the belt off the alternator and run it for a few seconds to see if it does the same thing.

A bad alternator with a blown diode can cause this.

BTW, some outboards also have alternators.

 

[-JR-]

I do have the resistor plugs ,and I have tried a new alternator as the sound does disappear when I unplug the Alternator.
Still making the noise

 

[HT32BSX115]

Crutchfield has a pretty good article on noise suppression in audio equipment. It's usually due to poor ground connections.


http://www.crutchfield.com/ISEO-rgb...car/noise_suppressors_installation_guide.html

 

[sam am I]

As quick diagnostic, you could open/disconnect the current power and ground wires from the back of the radio and temporary re-power the radio by splicing in and running both a new power and ground wires (could use an extension cord) back into the radio's power in connector/wires, DIRECTLY then powering the wires then to the battery's (assume you have a single battery boat?) pos and neg posts..........Fire up the motor, what happens?