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New KPA500 problem.

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SR Reynard

New KPA500 problem.

In a mild panic here. Need some wise advice.

Set up my brand new KPA500 and KAT500 today with my K3. Used only Elecraft cables and followed the wiring configuration carefully. Set the K3 for bypass of the internal ATU. All the KPA menu items are set to factory default.

When I power up the KPA the screen says INVALID. My limited understanding is that the KPA thinks it is being told to operate outside of its frequency range. But the K3 is set to 80m and well within the band edges.

My thinking is we have a failure to communicate in that the K3 is not sending the frequency to the KPA, perhaps sending no info at all.

Any thoughts? I’m assuming I have overlooked a simple setting on the K3 and/or the KPA.

Tnx and 73

Steve
KA4FOX
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Re: New KPA500 problem.

Steve;

The KPA is getting info that indicates that the input band is invalid. This is either coming from the radio’s BCD pins or from RF sampled by the KPA500. First thing to make sure is that the pins in the AUX cable are contacting properly, and are not bent and thus not plugging in properly. Check this on both cables, all four connectors.

Did you get this indication without transmitting any RF? If you did get it from an RF transmission, that would indicate that the sampled RF is outside the acceptable range of the KPA. This range is from 1.6 to 26 MHz and from 28 to 54 MHz.

Let’s see what we can do to gt you going - I may ask for a fault log if your checks don’t fix things so I can see exactly where the band problem is being picked up.

73,
Jack, W6FB
Elecraft Engineering

> On May 14, 2021, at 8:47 AM, Steve Fox <[hidden email]> wrote:
>
> In a mild panic here. Need some wise advice.
>
> Set up my brand new KPA500 and KAT500 today with my K3. Used only Elecraft cables and followed the wiring configuration carefully. Set the K3 for bypass of the internal ATU. All the KPA menu items are set to factory default.
>
> When I power up the KPA the screen says INVALID. My limited understanding is that the KPA thinks it is being told to operate outside of its frequency range. But the K3 is set to 80m and well within the band edges.
>
> My thinking is we have a failure to communicate in that the K3 is not sending the frequency to the KPA, perhaps sending no info at all.
>
> Any thoughts? I’m assuming I have overlooked a simple setting on the K3 and/or the KPA.
>
> Tnx and 73
>
> Steve
> KA4FOX
> ______________________________________________________________
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Ken Winterling

Re: New KPA500 problem.

In reply to this post by SR Reynard

How about disconnecting all cables except power, antenna, and keying line and testing if the amp operates properly with RF detection? Ken WA2LBI LG G6 ------ Original message------From: Jack Brindle via ElecraftDate: Fri, May 14, 2021 12:29To: Steve Fox;Cc: [hidden email];Subject:Re: [Elecraft] New KPA500 problem.Steve;

The KPA is getting info that indicates that the input band is invalid. This is either coming from the radio’s BCD pins or from RF sampled by the KPA500. First thing to make sure is that the pins in the AUX cable are contacting properly, and are not bent and thus not plugging in properly. Check this on both cables, all four connectors.

Did you get this indication without transmitting any RF? If you did get it from an RF transmission, that would indicate that the sampled RF is outside the acceptable range of the KPA. This range is from 1.6 to 26 MHz and from 28 to 54 MHz.

Let’s see what we can do to gt you going - I may ask for a fault log if your
checks don’t fix things so I can see exactly where the band problem is being picked up.

73,
Jack, W6FB
Elecraft Engineering

> On May 14, 2021, at 8:47 AM, Steve Fox wrote:
>
> In a mild panic here. Need some wise advice.
>
> Set up my brand new KPA500 and KAT500 today with my K3. Used only Elecraft cables and followed the wiring configuration carefully. Set the K3 for bypass of the internal ATU. All the KPA menu items are set to factory default.
>
> When I power up the KPA the screen says INVALID. My limited understanding is that the KPA thinks it is being told to operate outside of its frequency range. But the K3 is set to 80m and well within the band edges.
>
> My thinking is we have a failure to communicate in that the K3 is not sending the frequency to the KPA, perhaps sending no info at all.
>
> Any thoughts? I’m assuming I have overlooked a simple setting on the K3 and/or the KPA.
>
> Tnx and 73
>
> Steve
> KA4FOX
>

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ANDY DURBIN

New KPA500 problem.

In reply to this post by SR Reynard

"How about disconnecting all cables except power, antenna, and keying line and testing if the amp operates properly with RF detection?"

Why not start by eliminating everything except the KPA500?

Disconnect everything except KPA500 power and press each KPA500 band button. Observe KPA500 either displays the appropriate band frequency or it does not. If test works then add external band control (RF, AUX, or KPA Utility).

Andy, k3wyc
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Re: New KPA500 problem.

If you try this, be sure to set RADIO = BCD. If it is set to K3 (the default), then tapping a band button results in sending an AuxBus message to the K3, which will then change bands. With no K3 connected, nothing will happen.

Andy, you really should get a K3S or K4… <grin>

73!
Jack, W6FB

> On May 14, 2021, at 10:05 AM, Andy Durbin <[hidden email]> wrote:
>
> "How about disconnecting all cables except power, antenna, and keying line and testing if the amp operates properly with RF detection?"
>
> Why not start by eliminating everything except the KPA500?
>
> Disconnect everything except KPA500 power and press each KPA500 band button. Observe KPA500 either displays the appropriate band frequency or it does not. If test works then add external band control (RF, AUX, or KPA Utility).
>
> Andy, k3wyc
> ______________________________________________________________
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ANDY DURBIN

Re: New KPA500 problem.

"If you try this, be sure to set RADIO = BCD. If it is set to K3 (the default), then tapping a band button results in sending an AuxBus message to the K3, which will then change bands. With no K3 connected, nothing will happen."

Well my KPA500 must be broken. It changes bands with the band buttons with neither serial port connected and no AUX data source and with K3 selected as radio. It also changes bands with any other radio type selected.

Time for a code inspection?

73,
Andy, k3wyc

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Re: New KPA500 problem.

Nope, this one I remember. It depends on what is plugged into the AUXIO connector. If nothing, then the KPA will see the BAND signals all high and will assume that no K3 is connected. If a K3S is connected (or K3 with KIO3B), but off, then the same situation applies since the K3S will not pull the BAND signals to Vcc in this case. In this situation, it will then act the same as if RADIO is set to BCD and will change the band on its own in response to a band button press.

If a K3 with the original KIO3 board is connected, then the KPA will behave exactly as I described. in this case the KIO3 is pulling the BAND signals to Vcc (0V) and thus indicating 60 meters (even though it is off). The KPA will then believe the radio is active and will try to send the band info to the radio, but will not see a band change. It will thus stay on 60 meters.

So, it depends on the radio, but my original analysis is actually correct.

73!
Jack, W6FB

> On May 14, 2021, at 11:03 AM, Andy Durbin <[hidden email]> wrote:
>
> "If you try this, be sure to set RADIO = BCD. If it is set to K3 (the default), then tapping a band button results in sending an AuxBus message to the K3, which will then change bands. With no K3 connected, nothing will happen."
>
> Well my KPA500 must be broken. It changes bands with the band buttons with neither serial port connected and no AUX data source and with K3 selected as radio. It also changes bands with any other radio type selected.
>
> Time for a code inspection?
>
> 73,
> Andy, k3wyc

ANDY DURBIN

Re: New KPA500 problem.

"Nope, this one I remember. It depends on what is plugged into the AUXIO connector. If nothing, then the KPA will see the BAND signals all high and will assume that no K3 is connected. "

My test specification was - "Disconnect everything except KPA500 power and press each KPA500 band button. Observe KPA500 either displays the appropriate band frequency or it does not. If test works then add external band control (RF, AUX, or KPA Utility)."

I still think that test is valid but I admit that I had to test it when you raised the RADIO selection issue. As always though I learn something new when we exchange email.

Thanks and 73,
Andy, k3wyc

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