Try the other output on the keyer, you'd think the keyer would handle the
process, but you can't hurt anything by trying the paddle input.
Probably you have the cable pluged in to the wrong jack on the keyer though.
The old grid block radios had the oposite polorization on the jack, so you
would get exactly what you are reporting.


-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Tom Fowle
Sent: Saturday, February 20, 2016 1:35 AM
To: [log in to unmask]
Subject: Re: need help connecting MFJ-452 keyer to my TS590SG

Mike,
something doesn't make sense, I am puzzled there is any voltage on the
keyer's output in either state.  I'd think this should be either a reed
relay contact or an open collector transistor. The resistance measurements
make sense but the voltages don't. 

Is it possible there are two outputs on the keyer? one for old grid block
rigs and one for modern "positive key line" setups?

If this might be the case you may be using the wrong output?

Do you have an accessible manual for  the keyer?
Just to be sure, I assume if you plug a straight key into the Kenwood, it
works properly?

tom fowle WA6IVG

On Fri, Feb 19, 2016 at 08:51:33PM -0800, 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.