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K2 Lo P

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Jay S

K2 Lo P

Hello, I'm helping a friend who purchased a used K2. The K2 is a
serial number 6xxx with a KAT2, KSB2 and KBT2.

When tuning with the antenna tuner into a dummy load, sometimes The
message "Lo P" appears on the display. It would also give the "Hi
Curr" message with the current limit set to 2.5A. Does it seem right
that the radio would draw that much current when tuning into a dummy
load?

Any info on this would be appreciated. I'm finishing up the DSP, 160m
and KNB2 options for the radio but would like to get this fixed before
making changes.

Thanks & 73
Jay
W9IUF
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Don Wilhelm-4

Re: K2 Lo P

Jay,

The real answer is "it all depends".
Since this is a very recent K2 serial number, it may be that this
problem has been present since it was built and was the reason that the
original builder sold it - that is an unfortunate situation, but it must
be considered.

First, set your CAL CUR to 3.50 amps and try again.
LoP indicates that the K2 is not developing adequate power to enable
proper tuning for the KAT2 (it needs 2 watts to tune).

Then set the K2 ATU menu to CALP and see if it will do a TUNE into a
dummy load - first try at 5 watts power requested, then 10 watts and
finally at maximum requested power. Does the HI-CUR message appear at
all those power levels? Or only at maximum power?
Next, try each band separately (doing the tests as above). Does the
HI-CUR message appear on every band? or only some bands?

After those tests, set the ATU menu to AUTO and do a "TUNE" into the
dummy load. You should hear some relays click and after the tuner has
set its L and C values to match the 50 ohm load, it should exit from TUNE.

If all that does not produce satisfactory results, there is something
wrong with the K2. To troubleshoot it, the first step is to remove the
KAT2 and operate the base K2 directly into a 50 ohm non-inductive dummy
load. If it does not produce good power output without HI Cur messages,
then there is a problem with the base K2 - likely in the Low Pass
Filters or with the T4 output transformer. We can help further if we
have more specific information - what bands fail? what bands work? How
much power is really produced?

73,
Don W3FPR

Jay Sissom wrote:

> Hello, I'm helping a friend who purchased a used K2. The K2 is a
> serial number 6xxx with a KAT2, KSB2 and KBT2.
>
> When tuning with the antenna tuner into a dummy load, sometimes The
> message "Lo P" appears on the display. It would also give the "Hi
> Curr" message with the current limit set to 2.5A. Does it seem right
> that the radio would draw that much current when tuning into a dummy
> load?
>
> Any info on this would be appreciated. I'm finishing up the DSP, 160m
> and KNB2 options for the radio but would like to get this fixed before
> making changes.
>
> Thanks & 73
> Jay
> W9IUF
>
>

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Post: mailto:[hidden email]

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Jay S

Re: K2 Lo P

Thank you for your help. I'm at work right now, but will do more
research this weekend.

My friend has had the radio for a couple of weeks and has made
contacts on the radio so it mostly seems to work, but his Lo P message
appears once in a while and I've never seen it on my K2.

I changed the CAL CUR to 3.0 amps and the Hi Current message went away
(I tested 40m and 10m). But the Lo P message remained most of the
time. Tonight I'll do more testing with the wattmeter and get more
information to share.

I'll change the CAL CUR to 3.5 amps do the tests you recommend and get
back to you.

Thanks & 73
Jay
W9IUF

On Fri, Jun 19, 2009 at 12:56 AM, Don Wilhelm<[hidden email]> wrote:

> Jay,
>
> The real answer is "it all depends".
> Since this is a very recent K2 serial number, it may be that this problem
> has been present since it was built and was the reason that the original
> builder sold it - that is an unfortunate situation, but it must be
> considered.
>
> First, set your CAL CUR to 3.50 amps and try again.
> LoP indicates that the K2 is not developing adequate power to enable proper
> tuning for the KAT2 (it needs 2 watts to tune).
>
> Then set the K2 ATU menu to CALP and see if it will do a TUNE into a dummy
> load - first try at 5 watts power requested, then 10 watts and finally at
> maximum requested power. Does the HI-CUR message appear at all those power
> levels? Or only at maximum power?
> Next, try each band separately (doing the tests as above). Does the HI-CUR
> message appear on every band? or only some bands?
>
> After those tests, set the ATU menu to AUTO and do a "TUNE" into the dummy
> load. You should hear some relays click and after the tuner has set its L
> and C values to match the 50 ohm load, it should exit from TUNE.
>
> If all that does not produce satisfactory results, there is something wrong
> with the K2. To troubleshoot it, the first step is to remove the KAT2 and
> operate the base K2 directly into a 50 ohm non-inductive dummy load. If it
> does not produce good power output without HI Cur messages, then there is a
> problem with the base K2 - likely in the Low Pass Filters or with the T4
> output transformer. We can help further if we have more specific
> information - what bands fail? what bands work? How much power is really
> produced?
>
> 73,
> Don W3FPR
>
> Jay Sissom wrote:
>>
>> Hello, I'm helping a friend who purchased a used K2. The K2 is a
>> serial number 6xxx with a KAT2, KSB2 and KBT2.
>>
>> When tuning with the antenna tuner into a dummy load, sometimes The
>> message "Lo P" appears on the display. It would also give the "Hi
>> Curr" message with the current limit set to 2.5A. Does it seem right
>> that the radio would draw that much current when tuning into a dummy
>> load?
>>
>> Any info on this would be appreciated. I'm finishing up the DSP, 160m
>> and KNB2 options for the radio but would like to get this fixed before
>> making changes.
>>
>> Thanks & 73
>> Jay
>> W9IUF
>>
>

Jay S

Re: K2 Lo P

In reply to this post by Don Wilhelm-4

Don (& list),

I started doing some testing tonight and have narrowed it down.

I took out the antenna tuner and tested each band at the 2W setting,
5W & 10W setting on the power knob. I have an external watt meter and
dummy load attached. The power didn't match exactly on all the bands
but it was fairly close (between 1.9W - 3.5W on 2W setting, 4.9 - 7W
on 5W setting and 9W - >10W on the 10W setting). My Oak Hill WM2
meter only goes up to 10W.

Then I re-installed the antenna tuner and started the test again. I
connected to Ant 1 and had the ANT setting set to CALS. On 28060 the
2W setting measured 2W on the meter but gave an SWR of 1.4. At 5W it
was SWR 1.5 and at 10W it was SWR 3. The other bands were similar.
When I got to 21060 at 10W, the display said Hi Cur then showed an SWR
of 3. At 10106 with 10W, it also said Hi Cur then the radio shut down
and wouldn't come back on. I don't smell smoke or anything so I'm
assuming the fuse reset and I'll need to wait for it to cool down.

So it is definitely a problem with the antenna tuner. I think this
has already identified a problem and I shouldn't keep going with this
test. I'll take the antenna tuner out of the lid and look at it in
more detail. But of course, any other ideas would be appreciated.

Thanks & 73
Jay
W9IUF

On Fri, Jun 19, 2009 at 12:56 AM, Don Wilhelm<[hidden email]> wrote:

Jay S

Re: K2 Lo P

Here's an update. When the radio wouldn't come on after typing the
email, I was worried. I found out my cigar adapter plug from Radio
Shack has a 2A fuse in it and it was blown. So that would explain why
the radio wouldn't come back on! With my other power wire, I should
be back in business.

73
Jay
W9IUF

On Fri, Jun 19, 2009 at 9:08 PM, Jay Sissom<[hidden email]> wrote:

> Don (& list),
>
> I started doing some testing tonight and have narrowed it down.
>
> I took out the antenna tuner and tested each band at the 2W setting,
> 5W & 10W setting on the power knob. I have an external watt meter and
> dummy load attached. The power didn't match exactly on all the bands
> but it was fairly close (between 1.9W - 3.5W on 2W setting, 4.9 - 7W
> on 5W setting and 9W - >10W on the 10W setting). My Oak Hill WM2
> meter only goes up to 10W.
>
> Then I re-installed the antenna tuner and started the test again. I
> connected to Ant 1 and had the ANT setting set to CALS. On 28060 the
> 2W setting measured 2W on the meter but gave an SWR of 1.4. At 5W it
> was SWR 1.5 and at 10W it was SWR 3. The other bands were similar.
> When I got to 21060 at 10W, the display said Hi Cur then showed an SWR
> of 3. At 10106 with 10W, it also said Hi Cur then the radio shut down
> and wouldn't come back on. I don't smell smoke or anything so I'm
> assuming the fuse reset and I'll need to wait for it to cool down.
>
> So it is definitely a problem with the antenna tuner. I think this
> has already identified a problem and I shouldn't keep going with this
> test. I'll take the antenna tuner out of the lid and look at it in
> more detail. But of course, any other ideas would be appreciated.
>
> Thanks & 73
> Jay
> W9IUF
>
> On Fri, Jun 19, 2009 at 12:56 AM, Don Wilhelm<[hidden email]> wrote:
>> Jay,
>>
>> The real answer is "it all depends".
>> Since this is a very recent K2 serial number, it may be that this problem
>> has been present since it was built and was the reason that the original
>> builder sold it - that is an unfortunate situation, but it must be
>> considered.
>>
>> First, set your CAL CUR to 3.50 amps and try again.
>> LoP indicates that the K2 is not developing adequate power to enable proper
>> tuning for the KAT2 (it needs 2 watts to tune).
>>
>> Then set the K2 ATU menu to CALP and see if it will do a TUNE into a dummy
>> load - first try at 5 watts power requested, then 10 watts and finally at
>> maximum requested power. Does the HI-CUR message appear at all those power
>> levels? Or only at maximum power?
>> Next, try each band separately (doing the tests as above). Does the HI-CUR
>> message appear on every band? or only some bands?
>>
>> After those tests, set the ATU menu to AUTO and do a "TUNE" into the dummy
>> load. You should hear some relays click and after the tuner has set its L
>> and C values to match the 50 ohm load, it should exit from TUNE.
>>
>> If all that does not produce satisfactory results, there is something wrong
>> with the K2. To troubleshoot it, the first step is to remove the KAT2 and
>> operate the base K2 directly into a 50 ohm non-inductive dummy load. If it
>> does not produce good power output without HI Cur messages, then there is a
>> problem with the base K2 - likely in the Low Pass Filters or with the T4
>> output transformer. We can help further if we have more specific
>> information - what bands fail? what bands work? How much power is really
>> produced?
>>
>> 73,
>> Don W3FPR
>>
>> Jay Sissom wrote:
>>>
>>> Hello, I'm helping a friend who purchased a used K2. The K2 is a
>>> serial number 6xxx with a KAT2, KSB2 and KBT2.
>>>
>>> When tuning with the antenna tuner into a dummy load, sometimes The
>>> message "Lo P" appears on the display. It would also give the "Hi
>>> Curr" message with the current limit set to 2.5A. Does it seem right
>>> that the radio would draw that much current when tuning into a dummy
>>> load?
>>>
>>> Any info on this would be appreciated. I'm finishing up the DSP, 160m
>>> and KNB2 options for the radio but would like to get this fixed before
>>> making changes.
>>>
>>> Thanks & 73
>>> Jay
>>> W9IUF
>>>
>>
>

Don Wilhelm-4

Re: K2 Lo P

In reply to this post by Jay S

Jay,

It really sounds as though you have a problem with the wattmeter in the
KAT2.
Try balancing and calibrating the wattmeter again. If you cannot
achieve a good null with a good 50 ohm non-reactive dummy load, check T1
and its associated components (T1 for well tinned and soldered leads and
C34, R3, R4, D1 and D2 for god soldering and proper orientation).

If you cannot achieve a good null when balancing the wattmeter, stop and
ask for specific help. The null is a pre-requisite to proper calibration.

73,
Don W3FPR

Jay Sissom wrote:

> Don (& list),
>
> I started doing some testing tonight and have narrowed it down.
>
> I took out the antenna tuner and tested each band at the 2W setting,
> 5W & 10W setting on the power knob. I have an external watt meter and
> dummy load attached. The power didn't match exactly on all the bands
> but it was fairly close (between 1.9W - 3.5W on 2W setting, 4.9 - 7W
> on 5W setting and 9W - >10W on the 10W setting). My Oak Hill WM2
> meter only goes up to 10W.
>
> Then I re-installed the antenna tuner and started the test again. I
> connected to Ant 1 and had the ANT setting set to CALS. On 28060 the
> 2W setting measured 2W on the meter but gave an SWR of 1.4. At 5W it
> was SWR 1.5 and at 10W it was SWR 3. The other bands were similar.
> When I got to 21060 at 10W, the display said Hi Cur then showed an SWR
> of 3. At 10106 with 10W, it also said Hi Cur then the radio shut down
> and wouldn't come back on. I don't smell smoke or anything so I'm
> assuming the fuse reset and I'll need to wait for it to cool down.
>
> So it is definitely a problem with the antenna tuner. I think this
> has already identified a problem and I shouldn't keep going with this
> test. I'll take the antenna tuner out of the lid and look at it in
> more detail. But of course, any other ideas would be appreciated.
>
> Thanks & 73
> Jay
> W9IUF
>
> On Fri, Jun 19, 2009 at 12:56 AM, Don Wilhelm<[hidden email]> wrote:
>
>> Jay,
>>
>> The real answer is "it all depends".
>> Since this is a very recent K2 serial number, it may be that this problem
>> has been present since it was built and was the reason that the original
>> builder sold it - that is an unfortunate situation, but it must be
>> considered.
>>
>> First, set your CAL CUR to 3.50 amps and try again.
>> LoP indicates that the K2 is not developing adequate power to enable proper
>> tuning for the KAT2 (it needs 2 watts to tune).
>>
>> Then set the K2 ATU menu to CALP and see if it will do a TUNE into a dummy
>> load - first try at 5 watts power requested, then 10 watts and finally at
>> maximum requested power. Does the HI-CUR message appear at all those power
>> levels? Or only at maximum power?
>> Next, try each band separately (doing the tests as above). Does the HI-CUR
>> message appear on every band? or only some bands?
>>
>> After those tests, set the ATU menu to AUTO and do a "TUNE" into the dummy
>> load. You should hear some relays click and after the tuner has set its L
>> and C values to match the 50 ohm load, it should exit from TUNE.
>>
>> If all that does not produce satisfactory results, there is something wrong
>> with the K2. To troubleshoot it, the first step is to remove the KAT2 and
>> operate the base K2 directly into a 50 ohm non-inductive dummy load. If it
>> does not produce good power output without HI Cur messages, then there is a
>> problem with the base K2 - likely in the Low Pass Filters or with the T4
>> output transformer. We can help further if we have more specific
>> information - what bands fail? what bands work? How much power is really
>> produced?
>>
>> 73,
>> Don W3FPR
>>
>> Jay Sissom wrote:
>>
>>> Hello, I'm helping a friend who purchased a used K2. The K2 is a
>>> serial number 6xxx with a KAT2, KSB2 and KBT2.
>>>
>>> When tuning with the antenna tuner into a dummy load, sometimes The
>>> message "Lo P" appears on the display. It would also give the "Hi
>>> Curr" message with the current limit set to 2.5A. Does it seem right
>>> that the radio would draw that much current when tuning into a dummy
>>> load?
>>>
>>> Any info on this would be appreciated. I'm finishing up the DSP, 160m
>>> and KNB2 options for the radio but would like to get this fixed before
>>> making changes.
>>>
>>> Thanks & 73
>>> Jay
>>> W9IUF
>>>
>>>
> ______________________________________________________________
> 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 incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.339 / Virus Database: 270.12.80/2187 - Release Date: 06/19/09 06:53:00
>
>

Jay S

Re: K2 Lo P

Oops, I sent this to Don by himself, but thought I should send it to
the list just in case it helps someone.

Thanks Don, just an update. I re-nulled C55 and it nulled fine. When
I checked the voltage at U4 pin 1, it was 2.8V which was a little low.
Then I set R1 & R2. After doing that, the SWR into a dummy load is
1:9.9. I'll take the antenna tuner apart and look to see what I can
find.

Thanks & 73
Jay
W9IUF

On Sat, Jun 20, 2009 at 12:46 AM, Don Wilhelm<[hidden email]> wrote:

> Jay,
>
> It really sounds as though you have a problem with the wattmeter in the
> KAT2.
> Try balancing and calibrating the wattmeter again. If you cannot achieve a
> good null with a good 50 ohm non-reactive dummy load, check T1 and its
> associated components (T1 for well tinned and soldered leads and C34, R3,
> R4, D1 and D2 for god soldering and proper orientation).
>
> If you cannot achieve a good null when balancing the wattmeter, stop and ask
> for specific help. The null is a pre-requisite to proper calibration.
>
> 73,
> Don W3FPR
>
> Jay Sissom wrote:
>>
>> Don (& list),
>>
>> I started doing some testing tonight and have narrowed it down.
>>
>> I took out the antenna tuner and tested each band at the 2W setting,
>> 5W & 10W setting on the power knob. I have an external watt meter and
>> dummy load attached. The power didn't match exactly on all the bands
>> but it was fairly close (between 1.9W - 3.5W on 2W setting, 4.9 - 7W
>> on 5W setting and 9W - >10W on the 10W setting). My Oak Hill WM2
>> meter only goes up to 10W.
>>
>> Then I re-installed the antenna tuner and started the test again. I
>> connected to Ant 1 and had the ANT setting set to CALS. On 28060 the
>> 2W setting measured 2W on the meter but gave an SWR of 1.4. At 5W it
>> was SWR 1.5 and at 10W it was SWR 3. The other bands were similar.
>> When I got to 21060 at 10W, the display said Hi Cur then showed an SWR
>> of 3. At 10106 with 10W, it also said Hi Cur then the radio shut down
>> and wouldn't come back on. I don't smell smoke or anything so I'm
>> assuming the fuse reset and I'll need to wait for it to cool down.
>>
>> So it is definitely a problem with the antenna tuner. I think this
>> has already identified a problem and I shouldn't keep going with this
>> test. I'll take the antenna tuner out of the lid and look at it in
>> more detail. But of course, any other ideas would be appreciated.
>>
>> Thanks & 73
>> Jay
>> W9IUF
>>
>> On Fri, Jun 19, 2009 at 12:56 AM, Don Wilhelm<[hidden email]> wrote:
>>
>>>
>>> Jay,
>>>
>>> The real answer is "it all depends".
>>> Since this is a very recent K2 serial number, it may be that this problem
>>> has been present since it was built and was the reason that the original
>>> builder sold it - that is an unfortunate situation, but it must be
>>> considered.
>>>
>>> First, set your CAL CUR to 3.50 amps and try again.
>>> LoP indicates that the K2 is not developing adequate power to enable
>>> proper
>>> tuning for the KAT2 (it needs 2 watts to tune).
>>>
>>> Then set the K2 ATU menu to CALP and see if it will do a TUNE into a
>>> dummy
>>> load - first try at 5 watts power requested, then 10 watts and finally at
>>> maximum requested power. Does the HI-CUR message appear at all those
>>> power
>>> levels? Or only at maximum power?
>>> Next, try each band separately (doing the tests as above). Does the
>>> HI-CUR
>>> message appear on every band? or only some bands?
>>>
>>> After those tests, set the ATU menu to AUTO and do a "TUNE" into the
>>> dummy
>>> load. You should hear some relays click and after the tuner has set its
>>> L
>>> and C values to match the 50 ohm load, it should exit from TUNE.
>>>
>>> If all that does not produce satisfactory results, there is something
>>> wrong
>>> with the K2. To troubleshoot it, the first step is to remove the KAT2
>>> and
>>> operate the base K2 directly into a 50 ohm non-inductive dummy load. If
>>> it
>>> does not produce good power output without HI Cur messages, then there is
>>> a
>>> problem with the base K2 - likely in the Low Pass Filters or with the T4
>>> output transformer. We can help further if we have more specific
>>> information - what bands fail? what bands work? How much power is really
>>> produced?
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Jay Sissom wrote:
>>>
>>>>
>>>> Hello, I'm helping a friend who purchased a used K2. The K2 is a
>>>> serial number 6xxx with a KAT2, KSB2 and KBT2.
>>>>
>>>> When tuning with the antenna tuner into a dummy load, sometimes The
>>>> message "Lo P" appears on the display. It would also give the "Hi
>>>> Curr" message with the current limit set to 2.5A. Does it seem right
>>>> that the radio would draw that much current when tuning into a dummy
>>>> load?
>>>>
>>>> Any info on this would be appreciated. I'm finishing up the DSP, 160m
>>>> and KNB2 options for the radio but would like to get this fixed before
>>>> making changes.
>>>>
>>>> Thanks & 73
>>>> Jay
>>>> W9IUF
>>>>
>>>>
>>
>> ______________________________________________________________
>> 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 incoming message.
>> Checked by AVG - www.avg.com Version: 8.5.339 / Virus Database:
>> 270.12.80/2187 - Release Date: 06/19/09 06:53:00
>>
>>
>

Don Wilhelm-4

Re: K2 Lo P

Jay,

Don't tear into it too quickly. Make some methodical tests first.

TRUISM:
If you successfully obtained a null while connected to a dummy load, and
then left that same dummy load connected when you checked the SWR
reading, the SWR will read 1.0 - if it does not, your null was not correct.
End of truism.

An SWR of 9.9 usually indicates either a short or an open circuit - 9.9
is the highest SWR that is indicated by the K2. Be certain the coax
cable to your dummy load is good as a first step.
You could not have achieved a proper null if you have either an open
circuit or a short condition, so you will have to do the null again.

Before doing anything else, make a couple of 'sanity' measurements.
Set the ATU menu to CALP and set to ANT1, then power off and remove the
input coax to the KAT2 from the RF Board.
Measure the resistance from the input coax center conductor to the
center conductor of the ANT1 jack - it should measure zero ohms. Also
measure resistance from the center conductor of the ANT1 jack to the
shell - that should be very high (even infinite). If these measurements
do not check out properly, the path is not intact through the wattmeter
and relays K17 and K18 and that problem must be found before proceeding.

If the above checks were good, then connect the dummy load to ANT1 and
measure the resistance from the center conductor to the shield on the
input coax (with the input coax still unplugged) - it should measure 50
ohms. If not, stop and find the problem.

If all is well down to here, then put the KAT2 input coax back in place
and try the null again. If it anywhere near normal, the slot on C55
will be within 30 degrees of parallel with the long side of the KAT2
board. If it is perpendicular to the long side of the board, then the
capacitor is either at its minimum or maximum capacity point and you
have a problem with T1, R3, R4, C54 or C55. As usual, T1 is the most
likely suspect.

73,
Don W3FPR

Jay Sissom wrote:

> Oops, I sent this to Don by himself, but thought I should send it to
> the list just in case it helps someone.
>
>
>
> Thanks Don, just an update. I re-nulled C55 and it nulled fine. When
> I checked the voltage at U4 pin 1, it was 2.8V which was a little low.
> Then I set R1 & R2. After doing that, the SWR into a dummy load is
> 1:9.9. I'll take the antenna tuner apart and look to see what I can
> find.
>
> Thanks & 73
> Jay
> W9IUF
>
>
>

Jay S

Re: K2 Lo P

In reply to this post by Jay S

Too late. :) I noticed that two of the leads of T1 crossed over each
other under T1 and above the circuit board. They were tinned all the
way to the toroid so it looked like they might have been shorted. I
lifted the toroid a bit off the board and checked and got SWR of 1 to
1 on all bands. The tuner worked for a while when he first got the
radio so this could be the cause of the somewhat intermittent problem.

I attempted to remove T1 to fix the crossed wire. Unfortunately, the
person who built this folded each lead at a 90 degree angle under the
circuit board which made it extremely difficult to remove it and I had
to destroy T1 to remove it. I rebuilt it and reinstalled it and now
in CALn, I only get Hi no matter the position of C55. So I'm taking a
break and will get back at it.

I measured the resistance between the 4 leads out of the many turns
side of T1 and got 0 ohms like I should. So it seems it is connected
OK. Thanks again for your help. I'll look into it again later today.

Thanks & 73
Jay
W9IUF

On Sun, Jun 21, 2009 at 12:41 PM, Don Wilhelm<[hidden email]> wrote:

> Jay,
>
> Don't tear into it too quickly. Make some methodical tests first.
>
> TRUISM:
> If you successfully obtained a null while connected to a dummy load, and
> then left that same dummy load connected when you checked the SWR reading,
> the SWR will read 1.0 - if it does not, your null was not correct.
> End of truism.
>
> An SWR of 9.9 usually indicates either a short or an open circuit - 9.9 is
> the highest SWR that is indicated by the K2. Be certain the coax cable to
> your dummy load is good as a first step.
> You could not have achieved a proper null if you have either an open circuit
> or a short condition, so you will have to do the null again.
>
> Before doing anything else, make a couple of 'sanity' measurements.
> Set the ATU menu to CALP and set to ANT1, then power off and remove the
> input coax to the KAT2 from the RF Board.
> Measure the resistance from the input coax center conductor to the center
> conductor of the ANT1 jack - it should measure zero ohms. Also measure
> resistance from the center conductor of the ANT1 jack to the shell - that
> should be very high (even infinite). If these measurements do not check out
> properly, the path is not intact through the wattmeter and relays K17 and
> K18 and that problem must be found before proceeding.
>
> If the above checks were good, then connect the dummy load to ANT1 and
> measure the resistance from the center conductor to the shield on the input
> coax (with the input coax still unplugged) - it should measure 50 ohms. If
> not, stop and find the problem.
>
> If all is well down to here, then put the KAT2 input coax back in place and
> try the null again. If it anywhere near normal, the slot on C55 will be
> within 30 degrees of parallel with the long side of the KAT2 board. If it
> is perpendicular to the long side of the board, then the capacitor is either
> at its minimum or maximum capacity point and you have a problem with T1, R3,
> R4, C54 or C55. As usual, T1 is the most likely suspect.
>
> 73,
> Don W3FPR
>
>
>
> Jay Sissom wrote:
>>
>> Oops, I sent this to Don by himself, but thought I should send it to
>> the list just in case it helps someone.
>>
>>
>>
>> Thanks Don, just an update. I re-nulled C55 and it nulled fine. When
>> I checked the voltage at U4 pin 1, it was 2.8V which was a little low.
>> Then I set R1 & R2. After doing that, the SWR into a dummy load is
>> 1:9.9. I'll take the antenna tuner apart and look to see what I can
>> find.
>>
>> Thanks & 73
>> Jay
>> W9IUF
>>
>> On Sat, Jun 20, 2009 at 12:46 AM, Don Wilhelm<[hidden email]> wrote:
>>
>>>
>>> Jay,
>>>
>>> It really sounds as though you have a problem with the wattmeter in the
>>> KAT2.
>>> Try balancing and calibrating the wattmeter again. If you cannot achieve
>>> a
>>> good null with a good 50 ohm non-reactive dummy load, check T1 and its
>>> associated components (T1 for well tinned and soldered leads and C34, R3,
>>> R4, D1 and D2 for god soldering and proper orientation).
>>>
>>> If you cannot achieve a good null when balancing the wattmeter, stop and
>>> ask
>>> for specific help. The null is a pre-requisite to proper calibration.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>
>

Don Wilhelm-4

Re: K2 Lo P

Jay,

At least you now know the source of the difficulty.

Did you count the turns correctly? The first pass of the wire through
the core is one turn, a full wrap around the core is two turns.

You must get the proper leads into the right holes, and the leads must
be well stripped.
You did remember the single turn winding through the core when you put
it back on the board did you not.

73,
Don W3FPR

Jay Sissom wrote:

> Too late. :) I noticed that two of the leads of T1 crossed over each
> other under T1 and above the circuit board. They were tinned all the
> way to the toroid so it looked like they might have been shorted. I
> lifted the toroid a bit off the board and checked and got SWR of 1 to
> 1 on all bands. The tuner worked for a while when he first got the
> radio so this could be the cause of the somewhat intermittent problem.
>
> I attempted to remove T1 to fix the crossed wire. Unfortunately, the
> person who built this folded each lead at a 90 degree angle under the
> circuit board which made it extremely difficult to remove it and I had
> to destroy T1 to remove it. I rebuilt it and reinstalled it and now
> in CALn, I only get Hi no matter the position of C55. So I'm taking a
> break and will get back at it.
>
> I measured the resistance between the 4 leads out of the many turns
> side of T1 and got 0 ohms like I should. So it seems it is connected
> OK. Thanks again for your help. I'll look into it again later today.
>
> Thanks & 73
> Jay
> W9IUF
>
>
> On Sun, Jun 21, 2009 at 12:41 PM, Don Wilhelm<[hidden email]> wrote:
>
>> Jay,
>>
>> Don't tear into it too quickly. Make some methodical tests first.
>>
>> TRUISM:
>> If you successfully obtained a null while connected to a dummy load, and
>> then left that same dummy load connected when you checked the SWR reading,
>> the SWR will read 1.0 - if it does not, your null was not correct.
>> End of truism.
>>
>> An SWR of 9.9 usually indicates either a short or an open circuit - 9.9 is
>> the highest SWR that is indicated by the K2. Be certain the coax cable to
>> your dummy load is good as a first step.
>> You could not have achieved a proper null if you have either an open circuit
>> or a short condition, so you will have to do the null again.
>>
>> Before doing anything else, make a couple of 'sanity' measurements.
>> Set the ATU menu to CALP and set to ANT1, then power off and remove the
>> input coax to the KAT2 from the RF Board.
>> Measure the resistance from the input coax center conductor to the center
>> conductor of the ANT1 jack - it should measure zero ohms. Also measure
>> resistance from the center conductor of the ANT1 jack to the shell - that
>> should be very high (even infinite). If these measurements do not check out
>> properly, the path is not intact through the wattmeter and relays K17 and
>> K18 and that problem must be found before proceeding.
>>
>> If the above checks were good, then connect the dummy load to ANT1 and
>> measure the resistance from the center conductor to the shield on the input
>> coax (with the input coax still unplugged) - it should measure 50 ohms. If
>> not, stop and find the problem.
>>
>> If all is well down to here, then put the KAT2 input coax back in place and
>> try the null again. If it anywhere near normal, the slot on C55 will be
>> within 30 degrees of parallel with the long side of the KAT2 board. If it
>> is perpendicular to the long side of the board, then the capacitor is either
>> at its minimum or maximum capacity point and you have a problem with T1, R3,
>> R4, C54 or C55. As usual, T1 is the most likely suspect.
>>
>> 73,
>> Don W3FPR
>>
>>
>>
>> Jay Sissom wrote:
>>
>>> Oops, I sent this to Don by himself, but thought I should send it to
>>> the list just in case it helps someone.
>>>
>>>
>>>
>>> Thanks Don, just an update. I re-nulled C55 and it nulled fine. When
>>> I checked the voltage at U4 pin 1, it was 2.8V which was a little low.
>>> Then I set R1 & R2. After doing that, the SWR into a dummy load is
>>> 1:9.9. I'll take the antenna tuner apart and look to see what I can
>>> find.
>>>
>>> Thanks & 73
>>> Jay
>>> W9IUF
>>>
>>> On Sat, Jun 20, 2009 at 12:46 AM, Don Wilhelm<[hidden email]> wrote:
>>>
>>>
>>>> Jay,
>>>>
>>>> It really sounds as though you have a problem with the wattmeter in the
>>>> KAT2.
>>>> Try balancing and calibrating the wattmeter again. If you cannot achieve
>>>> a
>>>> good null with a good 50 ohm non-reactive dummy load, check T1 and its
>>>> associated components (T1 for well tinned and soldered leads and C34, R3,
>>>> R4, D1 and D2 for god soldering and proper orientation).
>>>>
>>>> If you cannot achieve a good null when balancing the wattmeter, stop and
>>>> ask
>>>> for specific help. The null is a pre-requisite to proper calibration.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>>
> ______________________________________________________________
> 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 incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.339 / Virus Database: 270.12.83/2191 - Release Date: 06/21/09 05:53:00
>
>

Jay S

Re: K2 Lo P

Thank you again for your help. I must have messed up the re-install
of T1. I removed it, then put it back and now everything works as it
should.

So blame this problem on T1 also - twice. Once the way we got the
radio and once that was my fault.

Now on to the KNB2, K160RX and KDSP2...

73
Thanks
Jay
W9IUF

On Sun, Jun 21, 2009 at 4:40 PM, Don Wilhelm<[hidden email]> wrote:

> Jay,
>
> At least you now know the source of the difficulty.
>
> Did you count the turns correctly? The first pass of the wire through the
> core is one turn, a full wrap around the core is two turns.
>
> You must get the proper leads into the right holes, and the leads must be
> well stripped.
> You did remember the single turn winding through the core when you put it
> back on the board did you not.
>
> 73,
> Don W3FPR
>
> Jay Sissom wrote:
>>
>> Too late. :) I noticed that two of the leads of T1 crossed over each
>> other under T1 and above the circuit board. They were tinned all the
>> way to the toroid so it looked like they might have been shorted. I
>> lifted the toroid a bit off the board and checked and got SWR of 1 to
>> 1 on all bands. The tuner worked for a while when he first got the
>> radio so this could be the cause of the somewhat intermittent problem.
>>
>> I attempted to remove T1 to fix the crossed wire. Unfortunately, the
>> person who built this folded each lead at a 90 degree angle under the
>> circuit board which made it extremely difficult to remove it and I had
>> to destroy T1 to remove it. I rebuilt it and reinstalled it and now
>> in CALn, I only get Hi no matter the position of C55. So I'm taking a
>> break and will get back at it.
>>
>> I measured the resistance between the 4 leads out of the many turns
>> side of T1 and got 0 ohms like I should. So it seems it is connected
>> OK. Thanks again for your help. I'll look into it again later today.
>>
>> Thanks & 73
>> Jay
>> W9IUF
>>
>>
>> On Sun, Jun 21, 2009 at 12:41 PM, Don Wilhelm<[hidden email]> wrote:
>>
>>>
>>> Jay,
>>>
>>> Don't tear into it too quickly. Make some methodical tests first.
>>>
>>> TRUISM:
>>> If you successfully obtained a null while connected to a dummy load, and
>>> then left that same dummy load connected when you checked the SWR
>>> reading,
>>> the SWR will read 1.0 - if it does not, your null was not correct.
>>> End of truism.
>>>
>>> An SWR of 9.9 usually indicates either a short or an open circuit - 9.9
>>> is
>>> the highest SWR that is indicated by the K2. Be certain the coax cable
>>> to
>>> your dummy load is good as a first step.
>>> You could not have achieved a proper null if you have either an open
>>> circuit
>>> or a short condition, so you will have to do the null again.
>>>
>>> Before doing anything else, make a couple of 'sanity' measurements.
>>> Set the ATU menu to CALP and set to ANT1, then power off and remove the
>>> input coax to the KAT2 from the RF Board.
>>> Measure the resistance from the input coax center conductor to the center
>>> conductor of the ANT1 jack - it should measure zero ohms. Also measure
>>> resistance from the center conductor of the ANT1 jack to the shell - that
>>> should be very high (even infinite). If these measurements do not check
>>> out
>>> properly, the path is not intact through the wattmeter and relays K17 and
>>> K18 and that problem must be found before proceeding.
>>>
>>> If the above checks were good, then connect the dummy load to ANT1 and
>>> measure the resistance from the center conductor to the shield on the
>>> input
>>> coax (with the input coax still unplugged) - it should measure 50 ohms.
>>> If
>>> not, stop and find the problem.
>>>
>>> If all is well down to here, then put the KAT2 input coax back in place
>>> and
>>> try the null again. If it anywhere near normal, the slot on C55 will be
>>> within 30 degrees of parallel with the long side of the KAT2 board. If
>>> it
>>> is perpendicular to the long side of the board, then the capacitor is
>>> either
>>> at its minimum or maximum capacity point and you have a problem with T1,
>>> R3,
>>> R4, C54 or C55. As usual, T1 is the most likely suspect.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>
>>>
>>> Jay Sissom wrote:
>>>
>>>>
>>>> Oops, I sent this to Don by himself, but thought I should send it to
>>>> the list just in case it helps someone.
>>>>
>>>>
>>>>
>>>> Thanks Don, just an update. I re-nulled C55 and it nulled fine. When
>>>> I checked the voltage at U4 pin 1, it was 2.8V which was a little low.
>>>> Then I set R1 & R2. After doing that, the SWR into a dummy load is
>>>> 1:9.9. I'll take the antenna tuner apart and look to see what I can
>>>> find.
>>>>
>>>> Thanks & 73
>>>> Jay
>>>> W9IUF
>>>>
>>>> On Sat, Jun 20, 2009 at 12:46 AM, Don Wilhelm<[hidden email]>
>>>> wrote:
>>>>
>>>>
>>>>>
>>>>> Jay,
>>>>>
>>>>> It really sounds as though you have a problem with the wattmeter in the
>>>>> KAT2.
>>>>> Try balancing and calibrating the wattmeter again. If you cannot
>>>>> achieve
>>>>> a
>>>>> good null with a good 50 ohm non-reactive dummy load, check T1 and its
>>>>> associated components (T1 for well tinned and soldered leads and C34,
>>>>> R3,
>>>>> R4, D1 and D2 for god soldering and proper orientation).
>>>>>
>>>>> If you cannot achieve a good null when balancing the wattmeter, stop
>>>>> and
>>>>> ask
>>>>> for specific help. The null is a pre-requisite to proper calibration.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>>
>>
>> ______________________________________________________________
>> 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 incoming message.
>> Checked by AVG - www.avg.com Version: 8.5.339 / Virus Database:
>> 270.12.83/2191 - Release Date: 06/21/09 05:53:00
>>
>>
>