[Elecraft] KIO2 noise problem

[Scott T Emery]

	I have a KIO2 in my K2.   When I attach the serial cable I built
to the K2, I get a lot of noise in the receiver.  I don't like the amount
of noise and therefore never use the KIO2.  Suggestions for measuring the
noise level (S meter is too widely varying) appreciated.

	Assuming that the noise level is unusual, I will proceed. My serial
cable is the maximum length and has no noise supression on it. It is built
correctly according to the manual. 
I have

	After a number of simple diagnostic steps I notice the following:
1) plugging the serial cable into either the K2 or the computer doesn't
	produce elevated noise levels.
2) unplugging the KIO2 from P4 on the control board (replacing the KATU
	plug) and connecting up the serial cable to the computer and KIO2
	produces elevated noise levels.
3) removing the KIO2 from the K2, plugging it into the Computer and touching
	the connector ground to the K2 case produces elevated noise levels.
4) plugging the serial cable into the computer and touching the connector
	metal shell to the K2 doesn't produce the elevated noise levels.
5) touching *any* of the connector pins from the serial cable (as in 4)
	causes elevated noise level, TxD, RxD, GND and the Shield wire
	all cause the elevated noise levels.

	I deduce that my serial cable is passing computer hash, and that
it is getting into the shield by induction.  I have not attempted to disable
the 16.29 Mhz crystal because of this assumption.  How do I kill the
computer hash on the shield (if that is in fact what is going on).