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  #11  
Old 11-19-2008, 11:35 AM
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Jamie Jamie is offline
 
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Default

Here are the isolation washers you should be using:

http://www.bandc.biz/cgi-bin/ez-cata...24X358218#s892
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  #12  
Old 11-19-2008, 03:13 PM
Mogli Mogli is offline
 
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Location: Goldsboro, NC
Posts: 36
Default alternator noise

Thanks all for your inputs.

Sorry, the "jack" is not isolated and is not required per the directions, it's suppose to ground at the jack. A possible solution to noise is to isolate the jack and run a ground from the jack to the intercom ground (again per directions). I tried that and it did not work. I've also tried multiple headsets and same noise on all. I've a second battery that I'm charging tonight and will try to switch out battery tomorrow. If that does not work I suppose the alternator might be suspect.

This is a new airplane, the intercom was used on another RV-8 and worked fine wired as it is in this one. The only change was going from an aircraft 60 amp alt with seperate voltage regulator to a plane power 60 amp internal regulator.

Thanks again for all the info,

Cheers,

Bill
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  #13  
Old 11-19-2008, 03:50 PM
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Ironflight Ironflight is offline
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Frustrating Bill, I know.....

What Intercom is it again? All of the newer ones that I have seen require that the shield on the jack wiring be grounded ONLY at the intercom end - grounding at both ends sets up a ground loop, and therefore a hummmm. It might be that earlier intercoms just didn't have that in their installation procedures. (That's why half the posters told you to check it - probably the most common cause of hum these days.)

One other thing to check - you haven't mentioned if you have anything else hooked in to the audio wiring - the 296/396/496 are notorious for causing a hum if they are plugged in to both the audio system and the 12 volt power supply - they use the same ground internally, so the audio is not isolated from the rest of the electrical system. Fortunately, they seem to have finally fixed that on the 696!

Probably doesn't help you much.

Paul
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  #14  
Old 05-16-2011, 04:12 PM
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Talking

a search on alt noise came up with 5 separate posts about noise. this post was the most active. most talk about stuff that a non builder like me just dont understand so i went another route. i put a 'filter' on the positive side of the alternator and my noise went by by. the filter is mounted on the belt adjusting bolt. we will see how this lasts.

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  #15  
Old 05-16-2011, 10:32 PM
billgill billgill is offline
 
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Location: Lee's Summit, MO
Posts: 99
Default Not a PlanePower

Alternator in the photo, but still a Nipendenso. I have had three PlanePower units lose a phase, which resulted in the motorboat sound you describe. The filter you installed may have masked the problem of a lost phase. If you have...say 14.3V with minimal load, but significantly less (12-13V) with a load of about 25 amps or more, then I would suspect a a bad diode or the loss of a stator winding (broken wire) in the alternator.

Best regards,

Bill
RV-7 N151WP
Lees Summit, MO
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  #16  
Old 05-19-2011, 05:47 AM
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bill, this alt was mounted last month. the old one had a IC diode going bad and made the same noise as this one. i have been dealing with the noise for years when flying at night with the lights on. daytime was bearable. very happy with the filter . about 30 bucks with one year warranty from chief parts.
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RV6-A 5,200+ hrs, R-44 1,600 hrs, Helicycle 320 hrs, gyro sold,35,000 miles flown in 2015
Stuart, Fl / S WINDSOR,Ct / Virgin Gorda, BVI - under major repair from hurricane damage
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  #17  
Old 01-22-2013, 05:30 PM
Speeddog7 Speeddog7 is offline
 
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Location: Plano, Texas
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Quote:
Originally Posted by turbo View Post
bill, this alt was mounted last month. the old one had a IC diode going bad and made the same noise as this one. i have been dealing with the noise for years when flying at night with the lights on. daytime was bearable. very happy with the filter . about 30 bucks with one year warranty from chief parts.
Can you give me the make/model filter you're using?
Thanks, Chad.
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  #18  
Old 01-22-2013, 05:59 PM
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http://www.chiefaircraft.com/lon-ls03-01004.html

good reading.......http://www.sacskyranch.com/altnoise.htm

good luck with the hummmm.
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Ed D'Arcy
RV6-A 5,200+ hrs, R-44 1,600 hrs, Helicycle 320 hrs, gyro sold,35,000 miles flown in 2015
Stuart, Fl / S WINDSOR,Ct / Virgin Gorda, BVI - under major repair from hurricane damage
VAF #840 EAA AOPA FAC FABA QB SPA
addicted pickle ball player
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  #19  
Old 01-12-2017, 11:57 AM
AirHound AirHound is offline
 
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Location: St Louis, MO
Posts: 323
Default ferrite nodes on headphone cable

Quote:
Originally Posted by turbo View Post
a search on alt noise came up with 5 separate posts about noise. this post was the most active. most talk about stuff that a non builder like me just dont understand so i went another route. i put a 'filter' on the positive side of the alternator and my noise went by by. the filter is mounted on the belt adjusting bolt. we will see how this lasts.

Anyone have an opine on putting 12$ ferrite modules on headphone cables?
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  #20  
Old 01-12-2017, 12:22 PM
rv7charlie rv7charlie is offline
 
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Location: Pocahontas MS
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It might make the noise less obvious, but it will be a band-aid; not a cure.
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