[Elecraft] [K3] KPA500 glitch - firmware bug?

[Jack Brindle]

This is not quite true. Indeed, when powered off from the front panel, most of the amplifier has its power removed, and things are placed into a powered-down state. The micro controller on the front panel board remains powered so that it can accept power-on commands, but pretty much everything else is shut down.

It sounds like the bypass relay either was not contacting on the receive side properly or the antenna was somehow otherwise disconnected from the amplifier receive path to the K3. Are you sure the K3 was set for the antenna port the amplifier was connected to? When the KPA powers up, it sends a "KPA powered on" message to the K3 which can cause the K3 to make changes. Perhaps this is what caused the antenna to be connected?

More details, please…

Jack Brindle, W6FB


On Apr 6, 2012, at 6:14 PM, Carl Clawson wrote:

> The other morning I powered up the station to have a listen but left the
> KPA500 off. The rear panel power switch was left on and I had powered the
> amp off the night before by the front panel switch.
> 
> There was no signal getting from the antenna to the K3, evidenced by absence
> of band noise on 160 m. I turned on the amp with the front panel switch and
> then it connected the antenna. (Why did I turn the amp on, you ask? I was
> going to poke a band button and try a different antenna.) Somehow the KPA500
> had "powered down" with its T/R switch in the wrong state. I put "powered
> down" in quotes because it's a software state, not an actual physical
> disconnection of power.
> 
> I suspect that if I'd powered down at the rear panel, I would have had an
> antenna. But I'll never know unless it happens again.
> 
> 73, Carl WS7L
> K3 #486 S/W V4.48
> KPA500 #750 S/W V1.11
> 
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