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K3 Power Amp Shut Down Problem

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Don Nelson

K3 Power Amp Shut Down Problem

Hi all,

My K3 appears to be working just fine once the power amp shut down problem was fixed. For months after I had assembled the K3, I would occasionally to frequently experience power amp shut down failures. The power amp shut down failures would occur while transmitting. The power amp shut down would occur sometime after I had been transmitting for a while and sometimes when I has been transmitting only for a very short time. This problem appeared to occur mostly on the 10m band.

The problem appears to have been an intermittent BNC connector on the coax cable that I was using. This cable worked fine on other radios but not the K3. When I changed the cable to the K3, the power amp shut down problem went away. I have been trouble free for about 6 weeks now.

Lessons learned: (a) use good cables with good connectors, (b) be aware that the K3 has hair trigger protection logic that shuts down the PA, (c.) the K3 needs to have messages displayed on the front panel when it decides to shut down the power amp giving a cause for that action, (d) the K3 documentation needs to enumerate the actions the firmware may take to change the state of the radio, in particular when the PA power is shut down.

Had I been able to read about the protection logic built into the firmware to protect the power amplifier, I would have saved months of frustration trying to figure out what was going on. It would be greatly appreciated by me and surely many others if the user manual would discuss the protection logic in the firmware and where and when power down actions will be taken.

Had the firmware reported protective action taken to shut down the power amp, this too would have hastened my taking corrective action. It would be so easy for the firmware to display, say on the VFOB display, that high SWR caused the power amp to be shut down.

Don Nelson, N0YE

wayne burdick

Re: K3 Power Amp Shut Down Problem

Administrator

Don Nelson wrote:

> My K3 appears to be working just fine once the power amp shut down
> problem
> was fixed....The problem appears to have been an intermittent BNC
> connector
> on the coax cable that I was using....

> (d) the K3 documentation needs to enumerate the actions the firmware
> may take
> to change the state of the radio, in particular when the PA power is
> shut down....

Hi Don,

Sorry to hear about the connector and/or K3 PA issues.

Regarding documentation, the K3 owner's manual has an extensive
troubleshooting section. Starts on page 61. The first item on page 61
(in the General troubleshooting section) mentions "ERR" messages that
you might see on the K3's display. This refers you to page 64 where
there's a full list of possible error codes.

More likely your K3 shut power down because the intermittent connector
presented a sudden change in SWR or PA current drain. In this case you
should have seen a HI CUR or HI SWR warning on the VFO B display. These
are described at the bottom of page 61 in the Transmit troubleshooting
section. Remedial actions include "check load Z" (impedance). These
warnings persist for a few seconds, and repeat until the K3 has dropped
power or gone into QRP mode. Of course you could have missed the
messages if you were looking somewhere else.

I'd like to improve the firmware or documentation where possible;
please send me any suggestions.

73,
Wayne
N6KR

---

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Don Nelson

Re: [Elecraft] K3 Power Amp Shut Down Problem

wayne burdick (via Nabble) wrote:

> Don Nelson wrote:
>
> > My K3 appears to be working just fine once the power amp shut down
> > problem
> > was fixed....The problem appears to have been an intermittent BNC
> > connector
> > on the coax cable that I was using....
>
> > (d) the K3 documentation needs to enumerate the actions the firmware
> > may take
> > to change the state of the radio, in particular when the PA power is
> > shut down....
>
> Hi Don,
>
> Sorry to hear about the connector and/or K3 PA issues.
>
> Regarding documentation, the K3 owner's manual has an extensive
> troubleshooting section. Starts on page 61. The first item on page 61
> (in the General troubleshooting section) mentions "ERR" messages that
> you might see on the K3's display. This refers you to page 64 where
> there's a full list of possible error codes.
>
> More likely your K3 shut power down because the intermittent connector
> presented a sudden change in SWR or PA current drain. In this case you
> should have seen a HI CUR or HI SWR warning on the VFO B display. These
> are described at the bottom of page 61 in the Transmit troubleshooting
> section. Remedial actions include "check load Z" (impedance). These
> warnings persist for a few seconds, and repeat until the K3 has dropped
> power or gone into QRP mode. Of course you could have missed the
> messages if you were looking somewhere else.
>
> I'd like to improve the firmware or documentation where possible;
> please send me any suggestions.
>
> 73,
> Wayne
> N6KR
>
>
>

Wayne,

Thank you for your response.

I do believe that the K3 cut power because the SWR on the antenna port
went too high. No I never saw any error message at any time. And that is
my point and basis for the request to have an error message for this
condition. Scanning the list of error messages on page 64 of the user
manual dated January 2009, I do not see any error message that states
that the SWR was detected to be too high.

Please let me know if you do implement such an error message.

Thanks.

Don Nelson, N0YE

Jim Wiley-2

Re: K3 Power Amp Shut Down Problem

In reply to this post by wayne burdick

Wayne -

I don't have a K3, yet, still just a K2/100. But, hoping order a K3
soon. But, this thread brings up an interesting question: If not
already implemented, is there a possibility of getting a "log" of the
last few errors? Perhaps the 10 most recent, particularly if time and
date could be appended, would be useful in troubleshooting. If an
error causes a rapid shutdown so that the on-screen messages are either
overlooked or pass by too rapidly to be seen, such a log would be a
great help in diagnosing what to do next. .

- Jim, KL7CC

wayne burdick wrote:
> D
> Regarding documentation, the K3 owner's manual has an extensive
> troubleshooting section. Starts on page 61. The first item on page 61
> (in the General troubleshooting section) mentions "ERR" messages that
> you might see on the K3's display. This refers you to page 64 where
> there's a full list of possible error codes.
>
>
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David Cutter

Re: K3 Power Amp Shut Down Problem

That would be of great benefit if you had an intermittent fault, such as a
fault in the antenna, particularly in a contest. Antenna faults are
probably the most common and an ERR message for high SWR sounds like a
really good idea.

David
G3UNA

----- Original Message -----
From: "Jim Wiley" <[hidden email]>
To: "wayne burdick" <[hidden email]>
Cc: <[hidden email]>
Sent: Saturday, May 23, 2009 3:06 AM
Subject: Re: [Elecraft] K3 Power Amp Shut Down Problem

>
> Wayne -
>
>
> I don't have a K3, yet, still just a K2/100. But, hoping order a K3
> soon. But, this thread brings up an interesting question: If not
> already implemented, is there a possibility of getting a "log" of the
> last few errors? Perhaps the 10 most recent, particularly if time and
> date could be appended, would be useful in troubleshooting. If an
> error causes a rapid shutdown so that the on-screen messages are either
> overlooked or pass by too rapidly to be seen, such a log would be a
> great help in diagnosing what to do next. .
>
>
> - Jim, KL7CC
>
>

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Don Wilhelm-4

Re: K3 Power Amp Shut Down Problem

David and all,

There already is a message for HI REFL which appears in the VFO B area
when the SWR exceeds 2.0.
It is transient and could possibly be overlooked. If a log of errors
could be made available, that might be helpful when troubleshooting.

73,
Don W3FPR

David Cutter wrote:
> That would be of great benefit if you had an intermittent fault, such as a
> fault in the antenna, particularly in a contest. Antenna faults are
> probably the most common and an ERR message for high SWR sounds like a
> really good idea.
>
> David
> G3UNA
>
>
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Don Nelson

Re: K3 Power Amp Shut Down Problem

Don Wilhelm wrote:

> David and all,
>
> There already is a message for HI REFL which appears in the VFO B area
> when the SWR exceeds 2.0.
> It is transient and could possibly be overlooked. If a log of errors
> could be made available, that might be helpful when troubleshooting.
>
> 73,
> Don W3FPR
>
> David Cutter wrote:
>
>> That would be of great benefit if you had an intermittent fault, such as a
>> fault in the antenna, particularly in a contest. Antenna faults are
>> probably the most common and an ERR message for high SWR sounds like a
>> really good idea.
>>
>> David
>> G3UNA
>>
>>
>>
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>
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>
>
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>

Don,

Interesting that you have a message reporting high SWR. I have never
seen it and I have had MANY chances to see if it indeed does get
displayed when a high SWR causes the power amp to be shut down.

Let's suppose for a moment that the mechanism that would display it did
not get executed. What other mechanism in the firmware would shut down
the power amp when I had the suspect cable connected and when the
suspect cable is replaced with a presumed better cable, I have no power
amp shut down? Am I to believe that there may be another problem? Any
suggestions?

Don, N0YE

Here is a copy of my original post:

Hi all,

My K3 appears to be working just fine once the power amp shut down problem
was fixed. For months after I had assembled the K3, I would occasionally to
frequently experience power amp shut down failures. The power amp shut down
failures would occur while transmitting. The power amp shut down would occur
sometime after I had been transmitting for a while and sometimes when I has
been transmitting only for a very short time. This problem appeared to occur
mostly on the 10m band.

The problem appears to have been an intermittent BNC connector on the coax
cable that I was using. This cable worked fine on other radios but not the
K3. When I changed the cable to the K3, the power amp shut down problem went
away. I have been trouble free for about 6 weeks now.

Lessons learned: (a) use good cables with good connectors, (b) be aware that
the K3 has hair trigger protection logic that shuts down the PA, (c.) the K3
needs to have messages displayed on the front panel when it decides to shut
down the power amp giving a cause for that action, (d) the K3 documentation
needs to enumerate the actions the firmware may take to change the state of
the radio, in particular when the PA power is shut down.

Had I been able to read about the protection logic built into the firmware
to protect the power amplifier, I would have saved months of frustration
trying to figure out what was going on. It would be greatly appreciated by
me and surely many others if the user manual would discuss the protection
logic in the firmware and where and when power down actions will be taken.

Had the firmware reported protective action taken to shut down the power
amp, this too would have hastened my taking corrective action. It would be
so easy for the firmware to display, say on the VFOB display, that high SWR
caused the power amp to be shut down.

Don Nelson, N0YE

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Don Wilhelm-4

Re: K3 Power Amp Shut Down Problem

Don,

I don't have any evidence to indicate that you have another problem
lurking around.
I would have to defer to Wayne for speculation about why you did not see
the HI SWR message yet experienced the PA shutdown. I do not know *all*
the details of the power shutdown mechanism (but high SWR is one
condition) and why no message was produced - Wayne would have to answer
that.

Can you reproduce it with the bad cable? If so, perhaps additional data
can be derived.

73,
Don W3FPR

Don Nelson wrote:

> Don,
>
> Interesting that you have a message reporting high SWR. I have never
> seen it and I have had MANY chances to see if it indeed does get
> displayed when a high SWR causes the power amp to be shut down.
>
> Let's suppose for a moment that the mechanism that would display it did
> not get executed. What other mechanism in the firmware would shut down
> the power amp when I had the suspect cable connected and when the
> suspect cable is replaced with a presumed better cable, I have no power
> amp shut down? Am I to believe that there may be another problem? Any
> suggestions?
>
> Don, N0YE
>
>
>

wayne burdick

Re: K3 Power Amp Shut Down Problem

Administrator

In reply to this post by Jim Wiley-2

Good idea, Jim. We could log all error messages and warnings in EEPROM,
and they could be extracted and displayed using K3 Utility.

73,
Wayne
N6KR

On May 22, 2009, at 7:06 PM, Jim Wiley wrote:

>
> Wayne -
>
>
> I don't have a K3, yet, still just a K2/100. But, hoping order a K3
> soon. But, this thread brings up an interesting question: If not
> already implemented, is there a possibility of getting a "log" of the
> last few errors? Perhaps the 10 most recent, particularly if time and
> date could be appended, would be useful in troubleshooting. If an
> error causes a rapid shutdown so that the on-screen messages are
> either overlooked or pass by too rapidly to be seen, such a log would
> be a great help in diagnosing what to do next. .

wayne burdick

Re: K3 Power Amp Shut Down Problem

Administrator

In reply to this post by Don Nelson

Hi Don,

You're right: "HI SWR" is a transitory message. It should probably
switch to a permanent message ("ERR SWR"), requiring a switch tap to
clear, if the conditions persists long enough to force a drop into QRP
mode.

73,
Wayne

On May 22, 2009, at 6:34 PM, Don Nelson wrote:

> Wayne,
>
> Thank you for your response.
>
> I do believe that the K3 cut power because the SWR on the antenna port
> went too high. No I never saw any error message at any time. And that
> is
> my point and basis for the request to have an error message for this
> condition. Scanning the list of error messages on page 64 of the user
> manual dated January 2009, I do not see any error message that states
> that the SWR was detected to be too high.
>
> Please let me know if you do implement such an error message.

westalto

Re: K3 Power Amp Shut Down Problem

I see the SWR message frequently when I've switched in the wrong antenna. (:-(

Doug, W6JD

----- Original Message -----
From: "wayne burdick" <[hidden email]>
To: "Don Nelson" <[hidden email]>
Cc: "Elecraft Reflector" <[hidden email]>
Sent: Saturday, May 23, 2009 9:41:34 AM GMT -08:00 US/Canada Pacific
Subject: Re: [Elecraft] K3 Power Amp Shut Down Problem

Hi Don,

You're right: "HI SWR" is a transitory message. It should probably
switch to a permanent message ("ERR SWR"), requiring a switch tap to
clear, if the conditions persists long enough to force a drop into QRP
mode.

73,
Wayne

On May 22, 2009, at 6:34 PM, Don Nelson wrote:

---

http://www.elecraft.com

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