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K2/100, half power output on 17-10M

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Jeff Kinzli N6GQ

K2/100, half power output on 17-10M

My K2/100 (#5945) has been working well lately, until I started
noticing higher output at times, more pronounced with higher SWR
antennas (i.e. it would more often spike it's output power if
connected to an antenna with more than 1.3:1 SWR, the output power
would rise to 140W).

About the same time, I started noticing lower output power on 10, 12,
15, and 17M. Output remains full on 20, 30, 40 and 80M.

Today I pulled the KPA100 apart, went though and checked and
resoldered everything around the SWR bridge, and anything that looked
remotely cold-soldered.

Put it back together, same issue (well, at least the lower power issue).

With a setting of anything over 50W, the max output is 50-52W, as
indicated on the K2 internal wattmeter, or my external wattmeter.

Any ideas why I'd only get half power on half the bands (and this is a
new occurrance, I was getting full power before).

Thanks for any ideas,

Jeff
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Jeff Kinzli N6GQ

Re: K2/100, half power output on 17-10M

Ok, strange...

Power-cycling the K2 *seems* to get my power back to 100%.

There have been a few times that I've noticed that power output seems
strange, and finding that turning the rig on/off/on seems to bring it
back.

So, is that an issue with relays being sticky, or...?

Thanks,

-Jeff

On 4/7/07, Jeff Kinzli N6GQ <[hidden email]> wrote:

> My K2/100 (#5945) has been working well lately, until I started
> noticing higher output at times, more pronounced with higher SWR
> antennas (i.e. it would more often spike it's output power if
> connected to an antenna with more than 1.3:1 SWR, the output power
> would rise to 140W).
>
> About the same time, I started noticing lower output power on 10, 12,
> 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>
> Today I pulled the KPA100 apart, went though and checked and
> resoldered everything around the SWR bridge, and anything that looked
> remotely cold-soldered.
>
> Put it back together, same issue (well, at least the lower power issue).
>
> With a setting of anything over 50W, the max output is 50-52W, as
> indicated on the K2 internal wattmeter, or my external wattmeter.
>
> Any ideas why I'd only get half power on half the bands (and this is a
> new occurrance, I was getting full power before).
>
> Thanks for any ideas,
>
> Jeff
>

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Post to: [hidden email]
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Don Wilhelm-3

Re: K2/100, half power output on 17-10M

In reply to this post by Jeff Kinzli N6GQ

Jeff,

Before we give any answer, we need to know the level of the KPA100.
Did you build it from the manual Revision D or the earlier Rev C?
Another way of checking - do you have a toroid at L15 and is RFC10 present?

It is not likely to be a sticking relay problem - that almost never
happens with the KPA100.

73,
Don W3FPR

Jeff Kinzli N6GQ wrote:

Jeff Kinzli N6GQ

Re: K2/100, half power output on 17-10M

Don, thanks, it's the newest KPA100, just bought/built it about a
month or two ago...

-Jeff

On 4/7/07, Don Wilhelm <[hidden email]> wrote:

> Jeff,
>
> Before we give any answer, we need to know the level of the KPA100.
> Did you build it from the manual Revision D or the earlier Rev C?
> Another way of checking - do you have a toroid at L15 and is RFC10 present?
>
> It is not likely to be a sticking relay problem - that almost never
> happens with the KPA100.
>
> 73,
> Don W3FPR
>
> Jeff Kinzli N6GQ wrote:
> > My K2/100 (#5945) has been working well lately, until I started
> > noticing higher output at times, more pronounced with higher SWR
> > antennas (i.e. it would more often spike it's output power if
> > connected to an antenna with more than 1.3:1 SWR, the output power
> > would rise to 140W).
> >
> > About the same time, I started noticing lower output power on 10, 12,
> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
> >
> > Today I pulled the KPA100 apart, went though and checked and
> > resoldered everything around the SWR bridge, and anything that looked
> > remotely cold-soldered.
> >
> > Put it back together, same issue (well, at least the lower power issue).
> >
> > With a setting of anything over 50W, the max output is 50-52W, as
> > indicated on the K2 internal wattmeter, or my external wattmeter.
> >
> > Any ideas why I'd only get half power on half the bands (and this is a
> > new occurrance, I was getting full power before).
> >
> > Thanks for any ideas,
> >
> > Jeff
>

Don Wilhelm-3

Re: K2/100, half power output on 17-10M

Jeff,

In that case, what is the size of C31? If it is the old .033 uF it must
be changed to the new .22 uF value. You can get one from Elecraft when
they get back in the office, but if you have two .1 uF caps with a
voltage rating of 50 volts or more, you can parallel them for the time
being.

73,
Don W3FPR

Jeff Kinzli N6GQ wrote:

> Don, thanks, it's the newest KPA100, just bought/built it about a
> month or two ago...
>
> -Jeff
>
> On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>> Jeff,
>>
>> Before we give any answer, we need to know the level of the KPA100.
>> Did you build it from the manual Revision D or the earlier Rev C?
>> Another way of checking - do you have a toroid at L15 and is RFC10
>> present?
>>
>> It is not likely to be a sticking relay problem - that almost never
>> happens with the KPA100.
>>
>> 73,
>> Don W3FPR
>>
>> Jeff Kinzli N6GQ wrote:
>> > My K2/100 (#5945) has been working well lately, until I started
>> > noticing higher output at times, more pronounced with higher SWR
>> > antennas (i.e. it would more often spike it's output power if
>> > connected to an antenna with more than 1.3:1 SWR, the output power
>> > would rise to 140W).
>> >
>> > About the same time, I started noticing lower output power on 10, 12,
>> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>> >
>> > Today I pulled the KPA100 apart, went though and checked and
>> > resoldered everything around the SWR bridge, and anything that looked
>> > remotely cold-soldered.
>> >
>> > Put it back together, same issue (well, at least the lower power
>> issue).
>> >
>> > With a setting of anything over 50W, the max output is 50-52W, as
>> > indicated on the K2 internal wattmeter, or my external wattmeter.
>> >
>> > Any ideas why I'd only get half power on half the bands (and this is a
>> > new occurrance, I was getting full power before).
>> >
>> > Thanks for any ideas,
>> >
>> > Jeff
>>
>

Jeff Kinzli N6GQ

Re: K2/100, half power output on 17-10M

Don, C31 is the new value, just replaced it a few weeks ago...

-J

On 4/7/07, Don Wilhelm <[hidden email]> wrote:

> Jeff,
>
> In that case, what is the size of C31? If it is the old .033 uF it must
> be changed to the new .22 uF value. You can get one from Elecraft when
> they get back in the office, but if you have two .1 uF caps with a
> voltage rating of 50 volts or more, you can parallel them for the time
> being.
>
> 73,
> Don W3FPR
>
> Jeff Kinzli N6GQ wrote:
> > Don, thanks, it's the newest KPA100, just bought/built it about a
> > month or two ago...
> >
> > -Jeff
> >
> > On 4/7/07, Don Wilhelm <[hidden email]> wrote:
> >> Jeff,
> >>
> >> Before we give any answer, we need to know the level of the KPA100.
> >> Did you build it from the manual Revision D or the earlier Rev C?
> >> Another way of checking - do you have a toroid at L15 and is RFC10
> >> present?
> >>
> >> It is not likely to be a sticking relay problem - that almost never
> >> happens with the KPA100.
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> Jeff Kinzli N6GQ wrote:
> >> > My K2/100 (#5945) has been working well lately, until I started
> >> > noticing higher output at times, more pronounced with higher SWR
> >> > antennas (i.e. it would more often spike it's output power if
> >> > connected to an antenna with more than 1.3:1 SWR, the output power
> >> > would rise to 140W).
> >> >
> >> > About the same time, I started noticing lower output power on 10, 12,
> >> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
> >> >
> >> > Today I pulled the KPA100 apart, went though and checked and
> >> > resoldered everything around the SWR bridge, and anything that looked
> >> > remotely cold-soldered.
> >> >
> >> > Put it back together, same issue (well, at least the lower power
> >> issue).
> >> >
> >> > With a setting of anything over 50W, the max output is 50-52W, as
> >> > indicated on the K2 internal wattmeter, or my external wattmeter.
> >> >
> >> > Any ideas why I'd only get half power on half the bands (and this is a
> >> > new occurrance, I was getting full power before).
> >> >
> >> > Thanks for any ideas,
> >> >
> >> > Jeff
> >>
> >
>

dave.wilburn

Re: K2/100, half power output on 17-10M

In reply to this post by Don Wilhelm-3

Ok, where do we find out more about this? I just finished inventory and
my C31 is a .033uF.

David Wilburn
[hidden email]
K4DGW
K2 #5982

Don Wilhelm wrote:

> Jeff,
>
> In that case, what is the size of C31? If it is the old .033 uF it must
> be changed to the new .22 uF value. You can get one from Elecraft when
> they get back in the office, but if you have two .1 uF caps with a
> voltage rating of 50 volts or more, you can parallel them for the time
> being.
>
> 73,
> Don W3FPR
>
> Jeff Kinzli N6GQ wrote:
>> Don, thanks, it's the newest KPA100, just bought/built it about a
>> month or two ago...
>>
>> -Jeff
>>
>> On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>>> Jeff,
>>>
>>> Before we give any answer, we need to know the level of the KPA100.
>>> Did you build it from the manual Revision D or the earlier Rev C?
>>> Another way of checking - do you have a toroid at L15 and is RFC10
>>> present?
>>>
>>> It is not likely to be a sticking relay problem - that almost never
>>> happens with the KPA100.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Jeff Kinzli N6GQ wrote:
>>> > My K2/100 (#5945) has been working well lately, until I started
>>> > noticing higher output at times, more pronounced with higher SWR
>>> > antennas (i.e. it would more often spike it's output power if
>>> > connected to an antenna with more than 1.3:1 SWR, the output power
>>> > would rise to 140W).
>>> >
>>> > About the same time, I started noticing lower output power on 10, 12,
>>> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>>> >
>>> > Today I pulled the KPA100 apart, went though and checked and
>>> > resoldered everything around the SWR bridge, and anything that looked
>>> > remotely cold-soldered.
>>> >
>>> > Put it back together, same issue (well, at least the lower power
>>> issue).
>>> >
>>> > With a setting of anything over 50W, the max output is 50-52W, as
>>> > indicated on the K2 internal wattmeter, or my external wattmeter.
>>> >
>>> > Any ideas why I'd only get half power on half the bands (and this is a
>>> > new occurrance, I was getting full power before).
>>> >
>>> > Thanks for any ideas,
>>> >
>>> > Jeff
>>>
>>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

Don Wilhelm-3

Re: K2/100, half power output on 17-10M

Dave,

FB that your C31 is .033 uF - but that alone is not an indicator. Do you
also have a toroid at L16 AND no RFC10 as well (and blue toroid cores
at L15 and RFC1)? All these things must go together. The prior design
KPA100 with RFC10 and L16 installed did properly use a .033 uF capacitor
at C31.

If you have no toroid at L16 and no RFC10, then request a .22 uF
capacitor for C31 from Elecraft.

If you do have an L16 toroid and RFC10 installed, the proper value for
C31 is .033 uF.

73,
Don W3FPR

David Wilburn wrote:

> Ok, where do we find out more about this? I just finished inventory and
> my C31 is a .033uF.
>
> David Wilburn
> [hidden email]
> K4DGW
> K2 #5982
>
>
> Don Wilhelm wrote:
>> Jeff,
>>
>> In that case, what is the size of C31? If it is the old .033 uF it
>> must be changed to the new .22 uF value. You can get one from
>> Elecraft when they get back in the office, but if you have two .1 uF
>> caps with a voltage rating of 50 volts or more, you can parallel them
>> for the time being.
>>
>> 73,
>> Don W3FPR
>>
>> Jeff Kinzli N6GQ wrote:
>>> Don, thanks, it's the newest KPA100, just bought/built it about a
>>> month or two ago...
>>>
>>> -Jeff
>>>
>>> On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>>>> Jeff,
>>>>
>>>> Before we give any answer, we need to know the level of the KPA100.
>>>> Did you build it from the manual Revision D or the earlier Rev C?
>>>> Another way of checking - do you have a toroid at L15 and is RFC10
>>>> present?
>>>>
>>>> It is not likely to be a sticking relay problem - that almost never
>>>> happens with the KPA100.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> Jeff Kinzli N6GQ wrote:
>>>> > My K2/100 (#5945) has been working well lately, until I started
>>>> > noticing higher output at times, more pronounced with higher SWR
>>>> > antennas (i.e. it would more often spike it's output power if
>>>> > connected to an antenna with more than 1.3:1 SWR, the output power
>>>> > would rise to 140W).
>>>> >
>>>> > About the same time, I started noticing lower output power on 10, 12,
>>>> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>>>> >
>>>> > Today I pulled the KPA100 apart, went though and checked and
>>>> > resoldered everything around the SWR bridge, and anything that looked
>>>> > remotely cold-soldered.
>>>> >
>>>> > Put it back together, same issue (well, at least the lower power
>>>> issue).
>>>> >
>>>> > With a setting of anything over 50W, the max output is 50-52W, as
>>>> > indicated on the K2 internal wattmeter, or my external wattmeter.
>>>> >
>>>> > Any ideas why I'd only get half power on half the bands (and this
>>>> is a
>>>> > new occurrance, I was getting full power before).
>>>> >
>>>> > Thanks for any ideas,
>>>> >
>>>> > Jeff
>>>>
>>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft Help:
>> http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>
>

Don Wilhelm-3

Re: K2/100, half power output on 17-10M

In reply to this post by Jeff Kinzli N6GQ

Jeff,

In that case, review the soldering (and toroid lead stripping) in the
wattmeter section. See the KPA100 schematic sheet 1 on the right side.
T4 and components attached to it, U5 and components associated, and U6
with its associated components. Q10 and Q11 play a role in the scaling
from low power to high power.

Do you have a problem at low power too? Remove power from the KPA100
and apply power only to the K2 coaxial power connector to investigate.

73,
Don W3FPR

Jeff Kinzli N6GQ wrote:

> Don, C31 is the new value, just replaced it a few weeks ago...
>
> -J
>
> On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>> Jeff,
>>
>> In that case, what is the size of C31? If it is the old .033 uF it must
>> be changed to the new .22 uF value. You can get one from Elecraft when
>> they get back in the office, but if you have two .1 uF caps with a
>> voltage rating of 50 volts or more, you can parallel them for the time
>> being.
>>
>> 73,
>> Don W3FPR
>>
>> Jeff Kinzli N6GQ wrote:
>> > Don, thanks, it's the newest KPA100, just bought/built it about a
>> > month or two ago...
>> >
>> > -Jeff
>> >
>> > On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>> >> Jeff,
>> >>
>> >> Before we give any answer, we need to know the level of the KPA100.
>> >> Did you build it from the manual Revision D or the earlier Rev C?
>> >> Another way of checking - do you have a toroid at L15 and is RFC10
>> >> present?
>> >>
>> >> It is not likely to be a sticking relay problem - that almost never
>> >> happens with the KPA100.
>> >>
>> >> 73,
>> >> Don W3FPR
>> >>
>> >> Jeff Kinzli N6GQ wrote:
>> >> > My K2/100 (#5945) has been working well lately, until I started
>> >> > noticing higher output at times, more pronounced with higher SWR
>> >> > antennas (i.e. it would more often spike it's output power if
>> >> > connected to an antenna with more than 1.3:1 SWR, the output power
>> >> > would rise to 140W).
>> >> >
>> >> > About the same time, I started noticing lower output power on 10,
>> 12,
>> >> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>> >> >
>> >> > Today I pulled the KPA100 apart, went though and checked and
>> >> > resoldered everything around the SWR bridge, and anything that
>> looked
>> >> > remotely cold-soldered.
>> >> >
>> >> > Put it back together, same issue (well, at least the lower power
>> >> issue).
>> >> >
>> >> > With a setting of anything over 50W, the max output is 50-52W, as
>> >> > indicated on the K2 internal wattmeter, or my external wattmeter.
>> >> >
>> >> > Any ideas why I'd only get half power on half the bands (and this
>> is a
>> >> > new occurrance, I was getting full power before).
>> >> >
>> >> > Thanks for any ideas,
>> >> >
>> >> > Jeff
>> >>
>> >
>>
>

dave.wilburn

Re: K2/100, half power output on 17-10M

In reply to this post by Don Wilhelm-3

I have a spot for L16, I did not inventory the toroids as I ordered
those from the toroid guy. I did not receive an RFC10, and I do not see
a spot for RFC10, though I am quite capable of missing it.

David Wilburn
[hidden email]
K4DGW
K2 #5982

Don Wilhelm wrote:

> Dave,
>
> FB that your C31 is .033 uF - but that alone is not an indicator. Do you
> also have a toroid at L16 AND no RFC10 as well (and blue toroid cores
> at L15 and RFC1)? All these things must go together. The prior design
> KPA100 with RFC10 and L16 installed did properly use a .033 uF capacitor
> at C31.
>
> If you have no toroid at L16 and no RFC10, then request a .22 uF
> capacitor for C31 from Elecraft.
>
> If you do have an L16 toroid and RFC10 installed, the proper value for
> C31 is .033 uF.
>
> 73,
> Don W3FPR
>
> David Wilburn wrote:
>> Ok, where do we find out more about this? I just finished inventory
>> and my C31 is a .033uF.
>>
>> David Wilburn
>> [hidden email]
>> K4DGW
>> K2 #5982
>>
>>
>> Don Wilhelm wrote:
>>> Jeff,
>>>
>>> In that case, what is the size of C31? If it is the old .033 uF it
>>> must be changed to the new .22 uF value. You can get one from
>>> Elecraft when they get back in the office, but if you have two .1 uF
>>> caps with a voltage rating of 50 volts or more, you can parallel them
>>> for the time being.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Jeff Kinzli N6GQ wrote:
>>>> Don, thanks, it's the newest KPA100, just bought/built it about a
>>>> month or two ago...
>>>>
>>>> -Jeff
>>>>
>>>> On 4/7/07, Don Wilhelm <[hidden email]> wrote:
>>>>> Jeff,
>>>>>
>>>>> Before we give any answer, we need to know the level of the KPA100.
>>>>> Did you build it from the manual Revision D or the earlier Rev C?
>>>>> Another way of checking - do you have a toroid at L15 and is RFC10
>>>>> present?
>>>>>
>>>>> It is not likely to be a sticking relay problem - that almost never
>>>>> happens with the KPA100.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>> Jeff Kinzli N6GQ wrote:
>>>>> > My K2/100 (#5945) has been working well lately, until I started
>>>>> > noticing higher output at times, more pronounced with higher SWR
>>>>> > antennas (i.e. it would more often spike it's output power if
>>>>> > connected to an antenna with more than 1.3:1 SWR, the output power
>>>>> > would rise to 140W).
>>>>> >
>>>>> > About the same time, I started noticing lower output power on 10,
>>>>> 12,
>>>>> > 15, and 17M. Output remains full on 20, 30, 40 and 80M.
>>>>> >
>>>>> > Today I pulled the KPA100 apart, went though and checked and
>>>>> > resoldered everything around the SWR bridge, and anything that
>>>>> looked
>>>>> > remotely cold-soldered.
>>>>> >
>>>>> > Put it back together, same issue (well, at least the lower power
>>>>> issue).
>>>>> >
>>>>> > With a setting of anything over 50W, the max output is 50-52W, as
>>>>> > indicated on the K2 internal wattmeter, or my external wattmeter.
>>>>> >
>>>>> > Any ideas why I'd only get half power on half the bands (and this
>>>>> is a
>>>>> > new occurrance, I was getting full power before).
>>>>> >
>>>>> > Thanks for any ideas,
>>>>> >
>>>>> > Jeff
>>>>>
>>>>
>>> _______________________________________________
>>> Elecraft mailing list
>>> Post to: [hidden email]
>>> You must be a subscriber to post to the list.
>>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>> http://mailman.qth.net/mailman/listinfo/elecraft Help:
>>> http://mailman.qth.net/subscribers.htm
>>> Elecraft web page: http://www.elecraft.com
>>>
>>
>