[Elecraft] PX3 noise generated on KX3-2M

[David Anderson]

That is how I fixed my problem then, I have connected the real common on the top of the socket to the flange which is connected to the case. I used a piece of copper tape as shown in last email photo. This stops the connection between the flange (case) and the common on the board being reliant on the plug being a tight fit in the barrel. 

It all makes sense now. 

Sorry if I had confused the situation with my description written from memory, but I did send photos clearly showing what I had done.  ;-)

I was adamant that this fixed a problem for me with radiated crud on 2m, especially annoying as it could be intermittent depending on how much pressure was applied sideways to the plug. 

This type of connector is used in other pieces of gear, like the KX3, is there a similar pin 1 type problem as a result of the same thing I wonder Alan?

I am sure you folks at Elecraft will come up with a more elegant solution than I did. :-)

73 from David GM4JJJ

> On 27 Feb 2016, at 18:19, Alan <n1al at sonic.net> wrote:
> 
> However I did find out something that was news to me. I had to remove the power supply board from the PX3 and do some more ohmmeter measurements to discover it.  It turns out that the metal body of the connector that screws to the panel is not connected to its ground pin! In other words, there is no electrical connection between the side panel and the ground pin (PCB ground plane) when the power plug is not inserted.
> 
> When the plug is inserted, the mounting flange and the ground pin are connected only through the plug's outer sleeve.  That solves the mystery of why wiggling the plug caused the radiated noise to go up and down. If the plug's sleeve does not make good contact with the connector flange, then there is a "pin 1" problem because the sleeve is grounded only via the PC board, which has a long return path to chassis ground.