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KPA500 suddenly low output - only 30 watts

mike
I was on a net this morning thinking I had my amp on (it did show OPER), however I found it was only putting out 30 watts. Moving to STBY I was putting out 95 watts with the K3 alone, but in OPER the KPA500 only put out 30. My per band setting showed the normal 24 watts (with the asterisk) but instead of 500w I was only getting 30 watts. I increased the K3 output to 70w and the KPA500 output increased to 50 watts.

I recently upgraded to 5.14 FW on the K3 and forgot to do the 50 watt calibration. I did go ahead on run the calibration just now, but the low KPA500 output remains the same.

Nothing else has changed.

Any suggestions? 73  ..mike  AI6II

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Re: KPA500 suddenly low output - only 30 watts

Ian Kahn
Mike,

I recently had a similar problem with my KPA500. A couple of components in
the low frequency T/R filter blew out. The amp made a trip back to the
Watsonville. I suggest checking with Elecraft support on this issue.

Hope this helps.

73 de,

--Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
[hidden email]
Please join me in the Georgia QSO Party April 11-12, 2015.  Info at
http://www.georgiaqsoparty.org.
10-10 #74624, North Georgia Chapter #2038
PODXS 070 #1962
K3# 281, P3 #688, KAT500 #860, KPA500 #1468

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of mike
Sent: Sunday, March 15, 2015 1:02 PM
To: [hidden email]
Subject: [Elecraft] KPA500 suddenly low output - only 30 watts

I was on a net this morning thinking I had my amp on (it did show OPER),
however I found it was only putting out 30 watts. Moving to STBY I was
putting out 95 watts with the K3 alone, but in OPER the KPA500 only put out
30. My per band setting showed the normal 24 watts (with the asterisk) but
instead of 500w I was only getting 30 watts. I increased the K3 output to
70w and the KPA500 output increased to 50 watts.

I recently upgraded to 5.14 FW on the K3 and forgot to do the 50 watt
calibration. I did go ahead on run the calibration just now, but the low
KPA500 output remains the same.

Nothing else has changed.

Any suggestions? 73  ..mike  AI6II





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Re: KPA500 suddenly low output - only 30 watts

Jack Brindle-2
In reply to this post by mike
When you key the K3, does an asterisk show up on the left side of the KPA’s LCD? If not, check the AUX or PTT connections to the KPA500.
Otherwise, let me know so I can follow up with you to get you going.

- Jack Brindle, W6FB
Elecraft Engineering

> On Mar 15, 2015, at 10:02 AM, mike <[hidden email]> wrote:
>
> I was on a net this morning thinking I had my amp on (it did show OPER),
> however I found it was only putting out 30 watts. Moving to STBY I was
> putting out 95 watts with the K3 alone, but in OPER the KPA500 only put out
> 30. My per band setting showed the normal 24 watts (with the asterisk) but
> instead of 500w I was only getting 30 watts. I increased the K3 output to
> 70w and the KPA500 output increased to 50 watts.
>
> I recently upgraded to 5.14 FW on the K3 and forgot to do the 50 watt
> calibration. I did go ahead on run the calibration just now, but the low
> KPA500 output remains the same.
>
> Nothing else has changed.
>
> Any suggestions? 73  ..mike  AI6II
>
>
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-suddenly-low-output-only-30-watts-tp7600292.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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Re: KPA500 suddenly low output - only 30 watts

mike
No, the asterisk on the KPA is missing. Nothing appears on the left of the KPA LCD. I understand that to mean the KPA is not receiving a valid PA KEY signal. I am using Elecrfat supplied AUX cables from the K3 to the KAT500 and another one from the KAT500 to the KPA.

I did recently change my antennas to the KAT500, removing the one that I had going to terminal 3. So in case there was a problem with the KAT500,  I just tested going from the KPA RF output directly to an antenna (removing the KAT500 from the circuit.) I also changed the AUX cable to go from the K3 directly to the KPA instead of going from the K3 to the KAT500 to the KPA as it is normally wired here. No change noted.  73 ..mike AI6II
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Re: KPA500 suddenly low output - only 30 watts

Jack Brindle-2
Mike;

It is definitely a cable problem. If the asterisk is not being displayed on key-down, then the
amplifier is not going to go into transmit. recheck the cables all the way from the K3 to the KPA
to see what came undone. Find and fix that and the KPA will come back to life.

You might want to ohm out the AUX cable going to the KPA to make sure everything is OK,
also, look for bent pins. The PTT signal is on pin 10 of the AUX cable, as described on page 18
of the KPA500 Operating manual.

Let us know what you find!

73,

- Jack B, W6FB


> On Mar 15, 2015, at 3:46 PM, mike <[hidden email]> wrote:
>
> No, the asterisk on the KPA is missing. Nothing appears on the left of the
> KPA LCD. I understand that to mean the KPA is not receiving a valid PA KEY
> signal. I am using Elecrfat supplied AUX cables from the K3 to the KAT500
> and another one from the KAT500 to the KPA.
>
> I did recently change my antennas to the KAT500, removing the one that I had
> going to terminal 3. So in case there was a problem with the KAT500,  I just
> tested going from the KPA RF output directly to an antenna (removing the
> KAT500 from the circuit.) I also changed the AUX cable to go from the K3
> directly to the KPA instead of going from the K3 to the KAT500 to the KPA as
> it is normally wired here. No change noted.  73 ..mike AI6II
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-suddenly-low-output-only-30-watts-tp7600292p7600312.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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Re: KPA500 suddenly low output - only 30 watts

Rick WA6NHC
Some of those connectors can be a bit finicky, wanting to be snugged up
a little more than common.

Ask me how I know...  wiggle, snug, wiggle snug.

Rick NHC

On 3/15/2015 4:04 PM, Jack Brindle wrote:

> Mike;
>
> It is definitely a cable problem. If the asterisk is not being displayed on key-down, then the
> amplifier is not going to go into transmit. recheck the cables all the way from the K3 to the KPA
> to see what came undone. Find and fix that and the KPA will come back to life.
>
> You might want to ohm out the AUX cable going to the KPA to make sure everything is OK,
> also, look for bent pins. The PTT signal is on pin 10 of the AUX cable, as described on page 18
> of the KPA500 Operating manual.
>
> Let us know what you find!
>
> 73,
>
> - Jack B, W6FB
>
>
>> On Mar 15, 2015, at 3:46 PM, mike <[hidden email]> wrote:
>>
>> No, the asterisk on the KPA is missing. Nothing appears on the left of the
>> KPA LCD. I understand that to mean the KPA is not receiving a valid PA KEY
>> signal. I am using Elecrfat supplied AUX cables from the K3 to the KAT500
>> and another one from the KAT500 to the KPA.
>>
>> I did recently change my antennas to the KAT500, removing the one that I had
>> going to terminal 3. So in case there was a problem with the KAT500,  I just
>> tested going from the KPA RF output directly to an antenna (removing the
>> KAT500 from the circuit.) I also changed the AUX cable to go from the K3
>> directly to the KPA instead of going from the K3 to the KAT500 to the KPA as
>> it is normally wired here. No change noted.  73 ..mike AI6II
>>
>>
>>
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-suddenly-low-output-only-30-watts-tp7600292p7600312.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
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Re: KPA500 suddenly low output - only 30 watts

mike
Yep, a finicky cable was apparently the problem. I disconnected the two E850463 AUX cables (KAT500 to KPA500 and KAT500 to K3 and swapped them, In doing so I discovered I had a gender bender on the cable end that plugged into the K3. It actually didn't change the gender (the K3 was a female and the gender changer was male to female...go figure) and was definitely not needed. Cannot explain how it got there! Anyway all is good now. Thanks all. 73  ..mike AI6II
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Re: KPA500 suddenly low output - only 30 watts

Phil Kane-2
On 3/17/2015 8:45 AM, mike wrote:
>  In
> doing so I discovered I had a gender bender on the cable end that plugged
> into the K3. It actually didn't change the gender (the K3 was a female and
> the gender changer was male to female...go figure)

That sounds more like a "null modem" than a "gender bender".  Could be
wrong.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Re: KPA500 suddenly low output - only 30 watts

mike
Nope, not a Null Modem, just a gender changer with the #10 pin clipped (upon closer inspection.) And I had written on it KL INT or maybe INT KL for which I have no idea as to the meaning. But no worries it all works great now. ;>)  73  ..mike  AI6II
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Re: KPA500 suddenly low output - only 30 watts

Ian Kahn
Perhaps you intended it as the line interrupt for the KPA500?

73 de,

--Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
[hidden email]
Please join me in the Georgia QSO Party April 11-12, 2015.  Info at
http://www.georgiaqsoparty.org.
10-10 #74624, North Georgia Chapter #2038
PODXS 070 #1962
K3# 281, P3 #688, KAT500 #860, KPA500 #1468

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of mike
Sent: Tuesday, March 17, 2015 4:11 PM
To: [hidden email]
Subject: Re: [Elecraft] KPA500 suddenly low output - only 30 watts

Nope, not a Null Modem, just a gender changer with the #10 pin clipped (upon
closer inspection.) And I had written on it KL INT or maybe INT KL for which
I have no idea as to the meaning. But no worries it all works great now. ;>)
73  ..mike  AI6II



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Re: KPA500 suddenly low output - only 30 watts

mike
Wait, it was not KL INT, but KY INT for 'key interrupter'. I think I have it figured out.

I recently sold my SteppIR vertical which required me to use the PTT Key line to prevent the amp from keying while the SteppIR was moving. This piece was used to interrupt the PTT in the AUX cables (missing the 10 pin.) So when I removed the cables for the PTT key lines, I just forgot to take this little part off.

Good, that 'splanins it and tells me I was not keying the amp for the last three and a half weeks. Maybe Elecraft should develop a flashing red light to warn a guy that he is not keying the amp when he thinks he is ..... just kidding!  73 ..mike  AI6II
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Re: KPA500 suddenly low output - only 30 watts

mike
In reply to this post by Ian Kahn
RIGHT! Ian wins the prize. Good for you.  73 ..mike AI6II
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Re: KPA500 suddenly low output - only 30 watts

Ian Kahn
Woo hoo! What'd I win? What'd I win?  :-)

--Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
[hidden email]
Please join me in the Georgia QSO Party April 11-12, 2015.  Info at
http://www.georgiaqsoparty.org.
10-10 #74624, North Georgia Chapter #2038
PODXS 070 #1962
K3# 281, P3 #688, KAT500 #860, KPA500 #1468

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of mike
Sent: Tuesday, March 17, 2015 4:32 PM
To: [hidden email]
Subject: Re: [Elecraft] KPA500 suddenly low output - only 30 watts

RIGHT! Ian wins the prize. Good for you.  73 ..mike AI6II



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Re: KPA500 suddenly low output - only 30 watts

mike
Well first of all, Ian, you won the right to yell Woo hoo and the knowledge that you beat out about three others who figured it out at the same time. Of course I also figured it out at the same time. Interestingly one fellow suggested I 'read my manual', which of course I do daily (smile), but I already knew the 10 pin controlled the the PTT inhibit. I just didn't realize the gender changer had the 10 pin removed until I picked it up again and saw the writing on it for the first time. Getting old and don't always see things at first glance.

And speaking of getting old this thread is going way past its due. So let's beat Wayne to the draw and close it!

Best 73 to all.  ..mike  AI6II
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Re: KPA500 suddenly low output - only 30 watts

Elecraft mailing list
In reply to this post by mike
That is the adapter to break the keying line


      From: mike <[hidden email]>
 To: [hidden email]
 Sent: Tuesday, March 17, 2015 11:45 AM
 Subject: Re: [Elecraft] KPA500 suddenly low output - only 30 watts
   
Yep, a finicky cable was apparently the problem. I disconnected the two
E850463 AUX cables (KAT500 to KPA500 and KAT500 to K3 and swapped them, In
doing so I discovered I had a gender bender on the cable end that plugged
into the K3. It actually didn't change the gender (the K3 was a female and
the gender changer was male to female...go figure) and was definitely not
needed. Cannot explain how it got there! Anyway all is good now. Thanks all.
73  ..mike AI6II



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Re: KPA500 suddenly low output - only 30 watts

Elecraft mailing list
In reply to this post by mike
Look on Page 11 of the KPA500 Manual


      From: mike <[hidden email]>
 To: [hidden email]
 Sent: Tuesday, March 17, 2015 4:10 PM
 Subject: Re: [Elecraft] KPA500 suddenly low output - only 30 watts
   
Nope, not a Null Modem, just a gender changer with the #10 pin clipped (upon
closer inspection.) And I had written on it KL INT or maybe INT KL for which
I have no idea as to the meaning. But no worries it all works great now. ;>)
73  ..mike  AI6II



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