[Elecraft] K3 RX Problem

[Allen Bush]

I just purchased a new to me K3-10 S/N 501.  I have discovered it has a RX sensitivity problem.  After some troubleshooting, I have discovered that the RX is not low on sensitivity (about .25 uV) but has a high noise level when receiving thru the ANT 1 or 2 ports.  The background noise with no antenna connected is 10 dB higher on the TX/RX ports than when it is receiving thru the RX only ports.  Possibly this is related to the PIN diode antenna switch?  Has anyone on the list experienced this?  Thanks!  Allen, W0OUU