radio noise filter

[Wizard765]

here we go with another problem... man you folks are patient.

 

Anyhow I've got a lot of static in my headsets. Enough that we don't want to use them. It is engine noise because it changes with the rpm of the engine.

 

I have an 84 which did not come with a C/B and have fitted one from a 90. What I'm hearing is the Mark II's have a noise filter. I have one that I picked up but cannot find anywhere that it plugs in.

So the question is.. Where does it plug in. Maybe my bike is missing that plug in the harness. Is there a diagram that I could follow to wire this up somehow.

I'm running out of ideas.

I pulled all the wires out of the bike and ran them across the top to eliminate the proximity to high tension wires. No help.

I pulled the stator wires out and got them away from the frame. Didn't help.

I'm really hoping a filter will help.

 

OK guys and gals... I'm hoping someone out there can help me get this figured out.

 

Wayne

[GeorgeS]

See page 7-99, for the 86 thru 93, 1st Gens. Block diagram for the Radio Section.

 

Note: item #77, " Noise Filter ( wireharness )

 

When you got the used equipment, did it include the Noise filter ??

 

Also, you can buy some Large " Electrolytic Capacitors" from Radio Shack and Install them in place of the 2 Caps shown on page 7-99.

[Marcarl]

Next thing would be to unplug the attenna from the radio and the CB and then see if you still have some noise, or else drop it by and we'll pull it apart and then see what happens. There are also noise filters that do both the ground and the positive, maybe get one of those and hook it in.

[Wizard765]

Thanks GeorgeS.

 

Yes I got the filter with the CB. I bought pretty much the whole package from a 90 at the time.

 

I will go through that diagram today. Thanks for the page number.

 

Marcarl:

 

Thanks for the phone call this morning. Between you and George I now have some things to work on. Hopefully something will work.

 

Wayne

[GeorgeS]

Sombody else on the site, sorry don't remember the name, was working on the same problem. ( by the way, I also have this problem on my 89 to some extent )

 

Anyway, he installed a couple extra large Electrolytic Caps, and as I recall he posted a few months later and claimed that this curred the problem on his bike.

 

One was installed, Just after the OutPut, Plug, " FROM " the Rectifyer/Regulator Unit. ( from the Two Red Wires , " TO " Ground )

 

I also suggest that you Check the " Main Ground " Stud, located Under the upper left fairing, inside the Radio mounting space. Its under the INNER Side Panel in that space. ( Left, and a little Fwd of the battery ) on the upper frame member.

There are about 5 black wires going to that ground point, remove and clean the wire connections. ( I also suggest you Re-Solder these Studs, to the black wires )

 

Also, BE SURE, that the Spark Plug Wires, have good connections, at the Ignition Coils, and the Plug Caps. ie: Screw off wires out of the plug caps, AND the Ignition coils, and nip off 1/4 inch of wire, and Re-Install. The center copper conductor, can be frayed, and Arching, at these points. Not very likly, but possible.

If the spark is jumping at those connections, you will never solve the problem. So, I highly reccomend you check this.

 

If you do this job, most likley you will have to pull out the Air Ceaner box, and this good time to replace the plug wires ( 7MM copper plug wire ) and clean and apply dialectreic greese to all other electrical plugs that are eaisly accessible with the box removed. ( TCI, Pressure Sensor, various other plugs, )

[Gearhead]

Yeah, that was me. Let's stop short of using the word "cured", but it did greatly reduce the noise problem.

 

Sounds like your problem is the same as mine - alternator whine thru the power wires. Stock filter is actually two filters in parallel - one in main hot wire and one in the battery back-up circuit. And there is a factory stock cap near the alternator plug as George said. I installed 3 new caps - two in the two radio hot lines and one near the alternator plug.

 

The other thing that helped me alot along the way was cleaning connections, especially ground connections. In fact, the single biggest change (other than new caps) was when I installed an extra 12 ga ground wire from the neg side of the regulator (soldered in) directly to the neg terminal of the battery. Also improved battery charging by .5 volt.

 

Does your noise decrease as you add electrical load? Mine is less if I:

 

- Run the blinkers (alternating of course - blinkers on, noise less)

- Turn on the driving lights

- Turn the Headset Attenuator on the handlebar or passenger pod down a notch and turn the radio volume up a tad to compensate. This makes a big difference.

- Turn the Auto Volume feature down to minimum (off, essentially)

 

Jeremy

[bongobobny]

Wayne, if you haven't fixed it yet, bring yourself down here with the bike and filter and we will see what we can do...

[Wizard765]

Gearhead:

 

Yes it sounds the same as yours. I've been experimenting. The volume of the noise only goes up and down with the volume of the intercom. If I turn the intercom down so that I cannot hear the static noise I can turn the radio or the CB up and things are fine. The problem is that I ride 2Up almost all the time and the communication is the most important part of the radio for us.

 

Bob:

 

I still have not "fixed" it yet and I may take you up on that offer. Would not be till next week sometime due to Wednesday being a holiday here and the weather is not looking so good at the moment either.

 

Wayne

[MiCarl]

Does your noise decrease as you add electrical load? Mine is less if I:

 

- Run the blinkers (alternating of course - blinkers on, noise less)

- Turn on the driving lights

 

That sounds like it could be regulator/rectifier related. It regulates the voltage by shunting excess output from the alternator to ground. When there is more load there is less excess to bleed off.

[Wizard765]

Ok guys at the risk of sounding less than inteligent... what is an Electrolytic Cap? Where do I get such an animal?

 

Wayne

[bongobobny]

We can get them at Radio Crap or believe it or not, Auto Zone, They are can type devices that once charged, resist a change in voltage. This is important if the noise is on the DC line for the amp...

[Wizard765]

soooo I would install these Caps inline on the power supply to the radio, CB or whatever I wanted the clean up? AND do they come in different sizes etc. What size do I need or what sort of markings am I looking for?

Edited June 30, 2009 by Wizard765

[timgray]

Alternator whine can be caused by 3 things.

 

1 - noisy voltage from your regulator going bad. only way to check is using a oscilliscope or frequency counter and check the voltage to ground with it.

 

2 - Bad ground causing a ground loop. If the system is getting the ground from the antenna then it's looping around the bike, clean and fix all ground wires to the exact same location to prevent this.

 

3 - the bike is radiating so much interference it's getting into everything. This can be checked with a battery powered FM radio. start up the bike and run the radio around the bike to find the source. Most of the time it's a bad regulator, bad coil, or bad ignition component causing RF interference.

 

If it's any of the above problems, no amount of filters and capacitors will fix it. Caps can minimize it, but never eliminate it. Capacitors used to be called filters in the olden days. if you use 3 different sizes, 1uf, 10uf and 100uf you filter out 3 different frequency ranges. From positive to ground they will short out the noise to ground if they can handle it. If there is a major problem it will simply overwhelm the capacitors or even make them pop and spill their guts.

 

The easiest thing is to check ALL the grounds for the audio and radio system. make new ones, make sure all are clean and a solid connection. Oh make sure the ground to the radio and amp is good, that means removing the screws they mount with and cleaning them up, I use a conductive copper paste on them to further make a good connection.

 

I knew those 6 years in Electronics Engineering college would be useful someday

[bongobobny]

Yah! The more microfarads the better, and a working voltage of 50 volts should do fine. They DO have polarity, so the + goes to +, and the - goes to ground. Yes, "dirty" grounds can indsuce noise and even cause what is known as feedback loops between 2 different ground points which cause random spurtaneous noise.

 

35 years as a component level electronics techincian also comes in handy...

[Gearhead]

Hmmm, my problem (much reduced now as I said) is with the radio or intercom, fairly equally. Interesting stuff about the possible causes.

 

I bought my caps at Radio Shack for about 5 bucks each. GeorgeS had taken apart a factory noise filter and told me the caps in there are 2200 microfarad, so I bought two of those. I installed a 4400 or so microfarad cap at the regulator. The higher the microfarads, the lower the frequency it filters out, FWIW. They go from the hot wire to ground.

 

Funny about the polarity, I didn't realize that and boiled one whilst learning the hard way.

 

Jeremy

[timgray]

...I bought my caps at Radio Shack for about 5 bucks each. ...

 

Wow they robbed you. I typically get most any cap that is under 6000uF for about $1.95 at the electronics place here in town. Radio shack has turned into a den of thieves if they are charging that much.

 

 

One of the best designs uses a Choke+cap. the cheapest I have seen is on amazon.com at

[ame=http://www.amazon.com/PAC-CSS12-Passive-Filter-Capacitor/dp/B000CEDZBA/ref=sr_1_3?ie=UTF8&s=automotive&qid=1246394984&sr=8-3]Amazon.com: PAC CSS12 Passive Noise Filter, 12 Amp, Choke And Capacitor Design: Automotive[/ame]

[Gearhead]

Yeah, Radio Shack is convenient though. That's good to know for next time.

 

The factory noise filter has a choke and a cap. As I understand it, the choke does not go bad so I left the noise filter in place and wired the caps in parallel.

 

Jeremy