K3 Erratic SSB Power Output

classic Classic list List threaded Threaded
6 messages Options
Reply | Threaded
Open this post in threaded view
|

K3 Erratic SSB Power Output

G8DX
Hello K3 Reflector.


I have an issue with my new K3/100 #7482. On SSB the peak power output isn't stable. The SSB power output fluctuates about +/- 15% of where it is set, but occasionally spikes to much more. The issue is on all bands but seems worse on 12/10m. I have tested the rig connected straight to a 1kW Bird 50ohm load and have tried 2 different linear power supplies. The problem is present using the two tone test feature, microphone or direct PC audio fed into the rig.


The real problem is: I set up my Acom 1000 at the legal limit here (400w) and the power output is all over the place, sometimes 150w, then maybe 500w, then 300w, then all of a sudden the power can spike to 1kW+. I operate mostly CW. Things seem more stable on CW, but compared to my previous Jap rigs (FT1000MP, FT990, TS850) etc, the power output is very difficult to properly regulate. On my previous rigs, I'd set them up to drive the Acom to a certain power level and they'd run for hours rock solid without a peep.


I've had an e-mail exchange with a friendly Elecraft Guy which resulted in me redoing the TX Gain calibration, he said the numbers looked good, but the problem persists. I am curious to see if anybody else has this issue and knows of a fix? As it is, the rig isn't much use to me.



Cheers



Jack G8DX 
______________________________________________________________
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
Reply | Threaded
Open this post in threaded view
|

Re: K3 Erratic SSB Power Output

Tim Hague
Jack, my K3 is stable, sounds to me that you might have a grounding problem or traces of feedback. Not an inherent problem with the K3

Best regards, Tim Hague, M0AFJ
Skype m0afj.Tim
Sent on my iPad


On 21 Jul 2013, at 20:12, JACK WHITE <[hidden email]> wrote:

> Hello K3 Reflector.
>
>
> I have an issue with my new K3/100 #7482. On SSB the peak power output isn't stable. The SSB power output fluctuates about +/- 15% of where it is set, but occasionally spikes to much more. The issue is on all bands but seems worse on 12/10m. I have tested the rig connected straight to a 1kW Bird 50ohm load and have tried 2 different linear power supplies. The problem is present using the two tone test feature, microphone or direct PC audio fed into the rig.
>
>
> The real problem is: I set up my Acom 1000 at the legal limit here (400w) and the power output is all over the place, sometimes 150w, then maybe 500w, then 300w, then all of a sudden the power can spike to 1kW+. I operate mostly CW. Things seem more stable on CW, but compared to my previous Jap rigs (FT1000MP, FT990, TS850) etc, the power output is very difficult to properly regulate. On my previous rigs, I'd set them up to drive the Acom to a certain power level and they'd run for hours rock solid without a peep.
>
>
> I've had an e-mail exchange with a friendly Elecraft Guy which resulted in me redoing the TX Gain calibration, he said the numbers looked good, but the problem persists. I am curious to see if anybody else has this issue and knows of a fix? As it is, the rig isn't much use to me.
>
>
>
> Cheers
>
>
>
> Jack G8DX  
> ______________________________________________________________
> 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
Reply | Threaded
Open this post in threaded view
|

Re: K3 Erratic SSB Power Output

alsopb
I second the grounding strap problem.
Through heat cycling or whatever, the ground nut of the back of my K3
became loose.  Had a series of weird problems with power.  Tightened it
up and the problems went away.

There is also the possibility that the cable between your K3 and the amp
is flaky.

73 de Brian/K3KO

On 7/21/2013 20:13, Tim Hague wrote:

> Jack, my K3 is stable, sounds to me that you might have a grounding problem or traces of feedback. Not an inherent problem with the K3
>
> Best regards, Tim Hague, M0AFJ
> Skype m0afj.Tim
> Sent on my iPad
>
>
> On 21 Jul 2013, at 20:12, JACK WHITE <[hidden email]> wrote:
>
>> Hello K3 Reflector.
>>
>>
>> I have an issue with my new K3/100 #7482. On SSB the peak power output isn't stable. The SSB power output fluctuates about +/- 15% of where it is set, but occasionally spikes to much more. The issue is on all bands but seems worse on 12/10m. I have tested the rig connected straight to a 1kW Bird 50ohm load and have tried 2 different linear power supplies. The problem is present using the two tone test feature, microphone or direct PC audio fed into the rig.
>>
>>
>> The real problem is: I set up my Acom 1000 at the legal limit here (400w) and the power output is all over the place, sometimes 150w, then maybe 500w, then 300w, then all of a sudden the power can spike to 1kW+. I operate mostly CW. Things seem more stable on CW, but compared to my previous Jap rigs (FT1000MP, FT990, TS850) etc, the power output is very difficult to properly regulate. On my previous rigs, I'd set them up to drive the Acom to a certain power level and they'd run for hours rock solid without a peep.
>>
>>
>> I've had an e-mail exchange with a friendly Elecraft Guy which resulted in me redoing the TX Gain calibration, he said the numbers looked good, but the problem persists. I am curious to see if anybody else has this issue and knows of a fix? As it is, the rig isn't much use to me.
>>
>>
>>
>> Cheers
>>
>>
>>
>> Jack G8DX
>> ______________________________________________________________
>> 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
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.2242 / Virus Database: 3204/6008 - Release Date: 07/21/13
>
>



-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2242 / Virus Database: 3204/6008 - Release Date: 07/21/13

______________________________________________________________
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
Reply | Threaded
Open this post in threaded view
|

Re: K3 Erratic SSB Power Output

Roger Crofts
In reply to this post by G8DX
Jack, G8DX, wrote that his K3 has erratic output.

I had the same fault on my kit-built K3 (ser # 6906)
In fact my problem was worse, because at times I had no output and, occasionally, the K3 (set to 20w) would drive my Metron Linear Amp with 110w causing the breaker to trip.
I followed the instructions from Elecraft support, and the problem improved, but it never went away completely.
After 6 months the problem got much worse until output power failed completely. This was a blessing, because it was then
easy to trace the fault. The fault was on the LPA board. Diode D1 was not soldered at both ends. Diode D1 is directly in the transmit path. It is a surface-mount device, and is not visible until the 100watt amplifier module is removed. Under the microscope, the contacts of this diode appeared slightly tarnished or dull.
In a normal manufacturing process, each circuit board is fitted with a solder mask, and solder paste is wiped across the mask. This deposits exactly the right amount of solder paste on each solder pad. Then a Pick-and-Place machine places the components on the pads. Then, the loaded boards move slowly on a conveyor belt through a re-flow oven. All the connections are made perfectly.
This process can occasionally go wrong. Because the contacts on D1 were slightly tarnished, the solder did not flow properly. The problem did not show up during testing at the factory because the contact was still touching the pad. Components come in batches, and if one diode has this problem, there may be other K3s out there with the same problem. If your K3 is showing this symptom, it might be a good idea to take a good look at the connections of D1 on the LPA board. After hand soldering the connections on D1, the output power from my K3 is now rock solid.

73, Roger, VK4YB
______________________________________________________________
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
Reply | Threaded
Open this post in threaded view
|

Re: K3 Erratic SSB Power Output

Terry Schieler-2
In reply to this post by G8DX
Jack,
I just sent my K3 (474) off to Elecraft service after wrestling with that same problem.  My TX output was suddenly all over the place.  The K3 power out bar graph showed 25% lower power than I had dialed up, but good, calibrated external watt meters were showing 40-50% higher power than what I had set on the K3.

After reading your post I wonder if a new version of Firm Ware might have caused something to go wack-o.

Terry W0FM


-----Original Message-----
From: JACK WHITE [mailto:[hidden email]]
Sent: Sunday, July 21, 2013 2:12 PM
To: [hidden email]
Subject: [Elecraft] K3 Erratic SSB Power Output

Hello K3 Reflector.


I have an issue with my new K3/100 #7482. On SSB the peak power output isn't stable. The SSB power output fluctuates about +/- 15% of where it is set, but occasionally spikes to much more. The issue is on all bands but seems worse on 12/10m. I have tested the rig connected straight to a 1kW Bird 50ohm load and have tried 2 different linear power supplies. The problem is present using the two tone test feature, microphone or direct PC audio fed into the rig.


The real problem is: I set up my Acom 1000 at the legal limit here (400w) and the power output is all over the place, sometimes 150w, then maybe 500w, then 300w, then all of a sudden the power can spike to 1kW+. I operate mostly CW. Things seem more stable on CW, but compared to my previous Jap rigs (FT1000MP, FT990, TS850) etc, the power output is very difficult to properly regulate. On my previous rigs, I'd set them up to drive the Acom to a certain power level and they'd run for hours rock solid without a peep.


I've had an e-mail exchange with a friendly Elecraft Guy which resulted in me redoing the TX Gain calibration, he said the numbers looked good, but the problem persists. I am curious to see if anybody else has this issue and knows of a fix? As it is, the rig isn't much use to me.



Cheers



Jack G8DX  


______________________________________________________________
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
Reply | Threaded
Open this post in threaded view
|

Re: K3 Erratic SSB Power Output

G8DX
Thanks to everybody that took the time to reply to my post.

Yesterday I took my rig to a different shack with a different ground, PSU, load, meter and feeder to eliminate any problems at my station, but sadly the problem is still there. The Array Solutions Power Master on the fast setting really demonstrated the problem clearly - here's a quick video of the issue (no mic connected - just two tone activated). The rig was set to about 50w and the power control wasn't touched during the video. Excuse the conversation in the background - but you get the idea!

http://youtu.be/Gl2k7gfelV4

Today I had the cases off and checked all the various pins and sockets were properly mated, I also had both the LPA and KPA out to double check them. I also had D1 on the LPA reworked but no change. Physically everything looks FB.

So far a bit disappointing and right on top of the IOTA Test. Currently in discussion with Elecraft about a resolution.

--
73 de G8DX/M




On 22 Jul 2013, at 17:32, "Terry Schieler" <[hidden email]> wrote:

> Jack,
> I just sent my K3 (474) off to Elecraft service after wrestling with that same problem.  My TX output was suddenly all over the place.  The K3 power out bar graph showed 25% lower power than I had dialed up, but good, calibrated external watt meters were showing 40-50% higher power than what I had set on the K3.
>
> After reading your post I wonder if a new version of Firm Ware might have caused something to go wack-o.
>
> Terry W0FM
>
>
> -----Original Message-----
> From: JACK WHITE [mailto:[hidden email]]
> Sent: Sunday, July 21, 2013 2:12 PM
> To: [hidden email]
> Subject: [Elecraft] K3 Erratic SSB Power Output
>
> Hello K3 Reflector.
>
>
> I have an issue with my new K3/100 #7482. On SSB the peak power output isn't stable. The SSB power output fluctuates about +/- 15% of where it is set, but occasionally spikes to much more. The issue is on all bands but seems worse on 12/10m. I have tested the rig connected straight to a 1kW Bird 50ohm load and have tried 2 different linear power supplies. The problem is present using the two tone test feature, microphone or direct PC audio fed into the rig.
>
>
> The real problem is: I set up my Acom 1000 at the legal limit here (400w) and the power output is all over the place, sometimes 150w, then maybe 500w, then 300w, then all of a sudden the power can spike to 1kW+. I operate mostly CW. Things seem more stable on CW, but compared to my previous Jap rigs (FT1000MP, FT990, TS850) etc, the power output is very difficult to properly regulate. On my previous rigs, I'd set them up to drive the Acom to a certain power level and they'd run for hours rock solid without a peep.
>
>
> I've had an e-mail exchange with a friendly Elecraft Guy which resulted in me redoing the TX Gain calibration, he said the numbers looked good, but the problem persists. I am curious to see if anybody else has this issue and knows of a fix? As it is, the rig isn't much use to me.
>
>
>
> Cheers
>
>
>
> Jack G8DX  
>
>
______________________________________________________________
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