[Elecraft] [KX3/PX3] Bonding

[Fred Moore]

much noise comes from and iMac from the USB cables, beads will greatly
reduce the noise... Fred


On 6/5/16 9:35 AM, John wrote:
> Can’t do that - with the iMac the power supply is built in…it’s an all-in-one. 
>
>
>
>
> On 5 Jun 2016, at 2:42 PM, Buck via Elecraft <elecraft at mailman.qth.net> wrote:
>
> Here is the authority on the issue. http://audiosystemsgroup.com/RFI-Ham.pdf
>
> Have you put ferrite on the cables from the iMac and the switching power supply?
>
> You've used "star" grounding around the KX3.  Try bonding everything to everything - you want to provide a low-impedance parallel path from case to case everywhere there is a connection. So, there should be a bond between the soundcard and the iMac and the soundcard and power supply.   Also the iMac and soundcard to the PX3.  Your diagram should look more like a spider web.
>
> Are the interconnecting cables grounded to the chassis or the circuit board?  You'll have to open some things up and see if there is the "pin 1 problem" where the cable's ground is on the circuit board and not the chassis.
>
> I would look for a YouTube video on how to open up that iMac.  I am sure someone has posted one.
>
> K4ia
> Buck
> Honor Roll 335
> 8BDXCC
>
>
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-- 
Fred Moore
email: fred at fmeco.com
       fred at safes.com
phone:  321-217-8699