Bulent Aliev wrote:

crimp connector splice that was done by my electronics engineer neighbor, totally loose. The metal part inside was blue from heat (created from the sparking I guess?). So I had it fixed. The noise is gone and me and my  flight captain are happy.

Hi All,

   Arcing should be black pits, not a blued pin or socket.  When a
connector is loose, it only makes contact on a very small portion of
the available contact surface, forcing all the current to go through
a very small point-of-contact.  This is the same as trying to push 20
Amps through a #18 wire.  It is called a high resistance connection.
What happens when current is pushed through an resistive object? 
Heat is generated.  Enough to turn the pin blue.

Dale R
COZY MkIV #1254