Autocom Prom M1 noise

[Steve Kolenda]

The Autocom system that I have installed on my R1100RT has all of a sudden gotten noisy. I am using the headsets and have a Garmin Streetpilot III connected. I first noticed the noise after the last service performed by the dealer. Before I pull the tuppy ware I thought I would try to eliminate the position of the wire running to the GPS. The noise is present if I turn the ignition on but do not start the bike. If I unplug the special Garmin cable from the GPS I hear no noise. If I plug the cable into the GPS but don't turn on the GPS I hear noise. If I turn the GPS on I hear an even louder and different pitched noise. My first thoughts were that the person who serviced my bike moved my carefull placed wire and it is now picking up some electrical noise. Seems very strange that the two things happend at the same time. Any help will be greatly appreciated.

[johnlt]

Steve, you might try running a different cable external from the GPS to the Autocom. If no noise, your original cable may be bad or had it's routing changed. Then you have to try the new cable in the old routing etc.

[Steve Kolenda]

John,

Thanks for your response. Unfortunately I do not have another cable with the same connections or long enough to reach.

[Tom B]

Just a thought

 

Your SP111 can be run off batteries and so if you have some batteries you could unplug the power cord from the SP111 and then try the SP111 with a standard music lead to Autocom?

 

However I have seen some SP111 spitting out a tone noise that I think is caused by the SP111 screen/display and it can affect the SP111 amplifier, which of course you will hear if plugged into your Autocom.

 

It could be something very simple like they have not plugged it all back in properly after servicing, so check that first.

 

You could try fitting an attenuating resistor into the Autocom isolation lead to help sink such noises.

 

First try a resistor across the +/- of the lead from the GPS where it solders onto the Autocom iso lead PCB, and if that doesn’t do it try across the output leads that goes to your Autocom?

 

I would guess trying about 470 ohms first, but reduce if required to about 68 ohms.

 

Hope that helps

 

Autocom-UK-Tom

[BMKrider]

You didn't mention if the noise has only just started ocuring perhaps after fitting the GPS and I guess Autocom Tom is the best source for info but, where on the Pro-1 have you got the GPS lead plugged into? If it's the phone socket as mine is you will need to fit Part 57 a splitter and isolator and then plug your GPS lead into that. This eliminates any earth/ground noise from the system (at least it did with mine). Since then I've been noise free.

 

Just a thought.

[Steve Kolenda]

Tom,

Thanks for the suggestion but at this time I am hesitant to add anything. Remember, this has been functioning for several years without a problem. So either something has changed with the SP III or the cable running to it. I am not an electronics expert but it seems strange to me that without the cable plugged into the back of the SP III there is no noise and then when I plugged it in there was noise even though the SP III was not on.