Turning ON KPA500 with K3?

[ke9uw]

How to turn on KPA500 by command from K3...and maybe even the operate power?

[ke9uw]

There is a line from the aux cable that will switch on and switch off...with a pulse low. But how to make the K3 send the pulse? Pin #8...but it, on the K3 aux connector is used to turn on the K3 with a pulse low. I think it, on the K3, comes from an output/input line from an open drain fet driven by a clock/calendar chip...so...and also I guess somehow from the POWER button on the K3 front panel to the MCU.
AND...I guess if pin #8 were not cut off on the aux 25pin cable Elecraft sent, then turning on the K3 would turn on the KPA500...what if they got out of sync?...then turning on the K3 would turn off the KPA500...and turning off the K3 would turn on the KPA500...hmmm...or is that not a problem?

[Andy Faber]

Chuck, For better or worse, I so far have used just a straight through
cable, not the Elecraft, modified version.  With this cable, the K3 does
turn on the KPA500 when the K3 is turned on.  However, while the K3 is on,
you can't turn off the KPA with the KPA front panel switch, and when you
turn off the K3, the KPA remains on.  So I'm not sure that is a preferable
mode of operation.
  73, andy ae6y

--------------------------------------------------
From: "ke9uw" <[hidden email]>
Sent: Sunday, August 28, 2011 2:01 PM
To: <[hidden email]>
Subject: Re: [Elecraft] Turning ON KPA500 with K3?

> There is a line from the aux cable that will switch on and switch
> off...with
> a pulse low. But how to make the K3 send the pulse? Pin #8...but it, on
> the
> K3 aux connector is used to turn on the K3 with a pulse low. I think it,
> on
> the K3, comes from an output/input line from an open drain fet driven by a
> clock/calendar chip...so...and also I guess somehow from the POWER button
> on
> the K3 front panel to the MCU.
> AND...I guess if pin #8 were not cut off on the aux 25pin cable Elecraft
> sent, then turning on the K3 would turn on the KPA500...what if they got
> out
> of sync?...then turning on the K3 would turn off the KPA500...and turning
> off the K3 would turn on the KPA500...hmmm...or is that not a problem?
>
> -----
> Chuck, KE9UW
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/Turning-ON-KPA500-with-K3-tp6734902p6735630.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html 

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[ke9uw]

Yes that makes sense. The pin #8 is power on for the K3, but power off on the K3 does not send a pulse to the pin now that I understand more about it. Incidentally, to remotely turn off the K3, you have to send a PS0 to the RS232 port. Maybe that's why they cut the pin off...since the function wouldn't be that useful and couldn't be disabled with CONFIG (I guess).
But I think I would like the option...an inline switch on my part would suffice for disabling the feature. Something to think about. Thanks for the info.

[ke9uw]

Probably a simple circuit using the "12 volts on" output would be the best approach to provide a neg pulse to the pin #8 to the KPA500 for both power on and power off. Also the pin #7 outputs a logic 5 volts when the K3 is turned on...another possibility.

[Don Wilhelm-4]

Chuck,

There was a good engineering reason for cutting pin #8 in the cable
between the K3 and the KPA500.
Use that connection at your own peril.  You may report "strange
happenings", but please do not complain about them.

73,
Don W3FPR

On 8/28/2011 5:01 PM, ke9uw wrote:

> There is a line from the aux cable that will switch on and switch off...with
> a pulse low. But how to make the K3 send the pulse? Pin #8...but it, on the
> K3 aux connector is used to turn on the K3 with a pulse low. I think it, on
> the K3, comes from an output/input line from an open drain fet driven by a
> clock/calendar chip...so...and also I guess somehow from the POWER button on
> the K3 front panel to the MCU.
> AND...I guess if pin #8 were not cut off on the aux 25pin cable Elecraft
> sent, then turning on the K3 would turn on the KPA500...what if they got out
> of sync?...then turning on the K3 would turn off the KPA500...and turning
> off the K3 would turn on the KPA500...hmmm...or is that not a problem?
>
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[ke9uw]

Ha. Ok on that...I wouldn't think of complaining about something like that. I guess you don't have to elaborate, but you have peaked my interest.



<quote author="Don Wilhelm-4">
Chuck,

There was a good engineering reason for cutting pin #8 in the cable
between the K3 and the KPA500.
Use that connection at your own peril.  You may report "strange
happenings", but please do not complain about them.

73,
Don W3FPR