Are you sure you are plugged into the right jack on the radio.    The 
straight key jack is the 1/8 jack and not the larger 1/4 jack.

73, Steve KW3A

On 2/19/2016 11:51 PM, Mike Keithley wrote:
> Hello list,
>
> I need help connecting my MFJ-452 keyer to my Kenwood TS590SG. This keyer is a keyboard-based system where you type on the keyboard to generate CW.
>
> My problem is that when I connect the keyer to the straight key jack on the back panel of the 590, the system behaves as if the key is frozen down and the sidetone is always on. It's as if the keyer's output is shorted.
>
> I checked the resistance at the keyer's output. It is over a meg-ohm when not sending code (key-up I suppose) and zero ohms when sending code (key down). I set my ohmmeter to continuity mode and hear code generated in the meter's speaker. I also checked the voltage across the keyer's output. The voltage was around plus 50 milivolts when the key was up and plus 0.75 volts when the key was down. However, I did these measurements with the Kenwood disconnected from the keyer. I believe the straight key is connected properly by noting that when I disconnect the cable from the keyer output, the side tone turns off.
>
> Again, the problem is that the Kenwood is behaving like the key is always down.
>
> Thank you for any help.
>