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Discussion Starter · #1 ·
Listening closely through some better quality phones and mellower music, I notice I have some alternator whine going on. Dealer in Sparks, NV also confirmed the whine using his special Autocom installer's headset. It really got bad when he keyed the intercom portion.

He told me to wire the Autocom to the GPS connector using the dealer supplied connector and not to run it through the Autocom Relay Switch as done by another dealer. He said its a "Ground Loop" problem. Ugh!

I've got the connector and figure I should run the hot wire to the striped (red-white) wire off the GPS plug and take the ground wire directly to the battery instead of going through the Canbus plug with the hot wire.

Sound good?


After that, he said to plug each accessory (Zumo, detector) in one by one and make sure nothing brings in the whine with it else I need to add a Ground Loop Isolator to it.

Out to tear off body panels...
 

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What model do you have this on? I know that when I originally mounted my Autocom on my '03 GT I put it in the tool tray which is just above the battery. I noticed that I could hear the alternator whine at certain speeds/volume levels. After doing some searching on this site and others I found other people experienced the same problem and solved it by moving the Autocom away from the battery. That's what I did and it whines no more!
 

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I don't have any of these gizmos yet but my wife says she wants to talk to me ( ?? ), but alternator whine can be picked up either as a radio interference or more likely as pickup on the power rails. Keeping the power leads short and getting them both on the battery terminals is best, but the Autocom box still might not have good suppression on its power lines inside the box.

If you can first try it with an external battery with no connection to the bike electrics, any pickup will be wireless interference needing a different solution. If the alternator interference goes away you confirm it's coming up the supply cable.

I haven't studied the autocom power needs, but if it's small you could try putting a 50-100 ohm 5 watt resistor in the power line with a 1000uf 25 volt capacitor between resistor and ground on the Autocom side of the resistor. The problem with alternator pickup is it's illusive - there when the battery is low (Winter?), less when the battery is fully charged (Summer?). If the resistor feels too warm, reduce its value. You can try this trick on most bike addons that don't need much power.



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Discussion Starter · #4 ·
voxmagna said:
....If you can first try it with an external battery with no connection to the bike electrics, any pickup will be wireless interference needing a different solution. If the alternator interference goes away you confirm it's coming up the supply cable.

I haven't studied the autocom power needs, but if it's small you could try putting a 50-100 ohm 5 watt resistor in the power line with a 1000uf 25 volt capacitor between resistor and ground on the Autocom side of the resistor. The problem with alternator pickup is it's illusive - there when the battery is low (Winter?), less when the battery is fully charged (Summer?). If the resistor feels too warm, reduce its value. You can try this trick on most bike addons that don't need much power.
Good idea on the external battery. I may try that this evening since all the panels are off. I remember the old Autocom came with a 9 volt snap-cap for the 9 volt battery. When I went to the bike for power is when the ground-loop problem showed up.
 

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My hum/whine/buzz dissapeared when I moved the autocom to the rear. In the little space by the back light. Now it is clean, rider to pillion and bike to bike at whatever revs the bike is doing.

I wired it to the rear side light circuit, (NOT THE BRAKE LIGHT CIRCUIT, IF ABS FITTED), after talking to our local Dealership (Southport Superbikes), and earthed it to the chassis directly, not the battery.

Problem solved.
 
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