[Elecraft] K3 - Key Out Question

[Don Wilhelm]

Jack,

Unless you have a problem with the K3, the KEYOUT jack should have no 
voltage on it either during TX or RX.
Check the KEYOUT with an ohmmeter.  It should have a high resistance 
during receive - then put the K3 into TEST (hold the MODE  up button), 
then press TUNE - the resistance should drop to almost zero.

With no cable connected to KEYOUT, you should not see any significant 
voltage at the K3 - if you do, double check your DMM connections.  Any 
voltage during key-up (or RX) will be coming from whatever you connect 
to KEYOUT - KEYOUT simply grounds the connection when TX is enabled.

73,
Don W3FPR

Jack Nelson wrote:
> Good evening. I'm attempting to use my K3 with a Tokyo High Power HL-1.2Kfx 
> amp. On the amp, when STBY (which has 12v on it) is grounded, the relay 
> clicks, and the "On Air" led lights....just like it should. However, when a 
> cable is connected between the K3's Key Out jack, and the STBY on the amp, 
> the amp shuts down with an "Over Drive" warning as soon as the K3 is keyed. 
> The K3's power is passed through the amp to the watt meter and dummy load.
>
> I noticed the Key Out jack on the K3 has 4.75vdc on it whether it's in the 
> Tune position or not. Is this normal. I don't think the amp likes seeing the 
> voltage from the K3.
>
> 73's Jack  K5FSE
> Treas  QRP ARCI
>   
>