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Help - K2 Higher Noise Level with X1 Selected

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VK1OO, Mike Walkington

Help - K2 Higher Noise Level with X1 Selected

Hi,

Another interesting problem with the K2. I've noticed that when
switching between the KSB2 filters, X1-X4, that there seems to be more
background noise on X1. And there is a similar increase in S meter bars.
On a quiet frequency with X1 selected, the S meter shows S8; X2-X4 show S2.
I'd certainly appreciate any suggestions about where to start
troubleshooting this one.

Mike
VK1OO
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Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

Mike,

I can't tell from your post just how much increase in noise you are hearing.
There will be an increase in the total noise heard just because the
bandwidth is increased - you will hear the total noise in the passband,
and when the passband is widened, the total noise will increase.

OTOH, if the increase is extreme, that would indicate a problem.

73,
Don W3FPR

On 6/2/2012 6:02 AM, VK1OO wrote:

> Hi,
>
> Another interesting problem with the K2. I've noticed that when
> switching between the KSB2 filters, X1-X4, that there seems to be more
> background noise on X1. And there is a similar increase in S meter bars.
> On a quiet frequency with X1 selected, the S meter shows S8; X2-X4 show S2.
> I'd certainly appreciate any suggestions about where to start
> troubleshooting this one.
>
>

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VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

Don,

Nice to hear from you again.
I had a similar thought from Jim, W4ATK.
I'm surprised the S-Meter is showing an additional 6 bars on X1. As I'm
listening to a quiet frequency I am assuming that's all additional
noise. Further that that is much more than seems justified by the
relatively difference in bandwidth.

I'm happy to simplify the question to, Why would the S Meter be showing
that much difference?

Mike
VK1OO

On 03-Jun-12 1:16 AM, Don Wilhelm wrote:

> Mike,
>
> I can't tell from your post just how much increase in noise you are
> hearing.
> There will be an increase in the total noise heard just because the
> bandwidth is increased - you will hear the total noise in the
> passband, and when the passband is widened, the total noise will
> increase.
>
> OTOH, if the increase is extreme, that would indicate a problem.
>
> 73,
> Don W3FPR
>
> On 6/2/2012 6:02 AM, VK1OO wrote:
>> Hi,
>>
>> Another interesting problem with the K2. I've noticed that when
>> switching between the KSB2 filters, X1-X4, that there seems to be more
>> background noise on X1. And there is a similar increase in S meter bars.
>> On a quiet frequency with X1 selected, the S meter shows S8; X2-X4
>> show S2.
>> I'd certainly appreciate any suggestions about where to start
>> troubleshooting this one.
>>
>>
>

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

Mike,

Yes, I would say that you have a significant difference there and it
indicates a problem of one nature or another.
What mode?
How did you set up the IF filters? Use Spectrogram. Look at my website
www.w3fpr.com article on K2 Dial Calibration - Part 3 deals with the
filter setup.
The reason I suspect the filter is that the XFIL 1 is a wide filter, and
if you did not offset the passband from zero frequency you will have the
BFO energy appearing in the output and that will influence the S-meter
response.

73,
Don W3FPR

On 6/2/2012 3:31 PM, VK1OO wrote:

> Don,
>
> Nice to hear from you again.
> I had a similar thought from Jim, W4ATK.
> I'm surprised the S-Meter is showing an additional 6 bars on X1. As
> I'm listening to a quiet frequency I am assuming that's all additional
> noise. Further that that is much more than seems justified by the
> relatively difference in bandwidth.
>
> I'm happy to simplify the question to, Why would the S Meter be
> showing that much difference?
>
> Mike
> VK1OO
>
> On 03-Jun-12 1:16 AM, Don Wilhelm wrote:
>> Mike,
>>
>> I can't tell from your post just how much increase in noise you are
>> hearing.
>> There will be an increase in the total noise heard just because the
>> bandwidth is increased - you will hear the total noise in the
>> passband, and when the passband is widened, the total noise will
>> increase.
>>
>> OTOH, if the increase is extreme, that would indicate a problem.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/2/2012 6:02 AM, VK1OO wrote:
>>> Hi,
>>>
>>> Another interesting problem with the K2. I've noticed that when
>>> switching between the KSB2 filters, X1-X4, that there seems to be more
>>> background noise on X1. And there is a similar increase in S meter
>>> bars.
>>> On a quiet frequency with X1 selected, the S meter shows S8; X2-X4
>>> show S2.
>>> I'd certainly appreciate any suggestions about where to start
>>> troubleshooting this one.
>>>
>>>
>>
>

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

Hi Don,

SSB.
I used your method, some years ago now, to set up the filters.
The problem has appeared recently, so something has changed.

Mike

On 03-Jun-12 5:44 AM, Don Wilhelm wrote:

> Mike,
>
> Yes, I would say that you have a significant difference there and it
> indicates a problem of one nature or another.
> What mode?
> How did you set up the IF filters? Use Spectrogram. Look at my
> website www.w3fpr.com article on K2 Dial Calibration - Part 3 deals
> with the filter setup.
> The reason I suspect the filter is that the XFIL 1 is a wide filter,
> and if you did not offset the passband from zero frequency you will
> have the BFO energy appearing in the output and that will influence
> the S-meter response.
>
> 73,
> Don W3FPR
>
> On 6/2/2012 3:31 PM, VK1OO wrote:
>> Don,
>>
>> Nice to hear from you again.
>> I had a similar thought from Jim, W4ATK.
>> I'm surprised the S-Meter is showing an additional 6 bars on X1. As
>> I'm listening to a quiet frequency I am assuming that's all
>> additional noise. Further that that is much more than seems justified
>> by the relatively difference in bandwidth.
>>
>> I'm happy to simplify the question to, Why would the S Meter be
>> showing that much difference?
>>
>> Mike
>> VK1OO
>>
>> On 03-Jun-12 1:16 AM, Don Wilhelm wrote:
>>> Mike,
>>>
>>> I can't tell from your post just how much increase in noise you are
>>> hearing.
>>> There will be an increase in the total noise heard just because the
>>> bandwidth is increased - you will hear the total noise in the
>>> passband, and when the passband is widened, the total noise will
>>> increase.
>>>
>>> OTOH, if the increase is extreme, that would indicate a problem.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 6/2/2012 6:02 AM, VK1OO wrote:
>>>> Hi,
>>>>
>>>> Another interesting problem with the K2. I've noticed that when
>>>> switching between the KSB2 filters, X1-X4, that there seems to be more
>>>> background noise on X1. And there is a similar increase in S meter
>>>> bars.
>>>> On a quiet frequency with X1 selected, the S meter shows S8; X2-X4
>>>> show S2.
>>>> I'd certainly appreciate any suggestions about where to start
>>>> troubleshooting this one.
>>>>
>>>>
>>>
>>
>

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

In reply to this post by Don Wilhelm-4

Don,

The effect happens when the antenna is disconnected as well as when
connected.
And in SBB and CW

SSB Filter Widths
X1 = OP1
X2 = 2.4
X3 = 2.1
X4 = 1.8

CW Filter Widths
X1 = OP1
X2 = 0.7
X3 = 0.4
X4 = 0.1

I assume something is going wrong in the 4.915MHz Variable Bandwidth
Crystal Filter.

Mike

On 03-Jun-12 5:44 AM, Don Wilhelm wrote:

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

In reply to this post by VK1OO, Mike Walkington

Mike,

OK, what I now suspect is that you have developed a fault in the IF
filter on the RF Board. My suspicion is that the OP1 filter on the KSB2
option is working just fine, but all the filters created using the
variable bandwidth filter have a lesser response than they did.

I would suggest that the most likely cause is a solder connection - yes
even after several years, so re-flow the solder in the xtal filter area
adding a bit of additional solder (actually what is needed is a bit of
flux). Use a hot iron - 400 degC.

73,
Don W3FPR

On 6/2/2012 4:11 PM, VK1OO wrote:
> Hi Don,
>
> SSB.
> I used your method, some years ago now, to set up the filters.
> The problem has appeared recently, so something has changed.
>
> Mike
>
>
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Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

In reply to this post by VK1OO, Mike Walkington

Mike,

If you do not find the solution re-flowing the solder on the RF board
filter area, the problem source may be on the KSB2 board in the
switching diodes and/or resistors at the filter end of that board, so
for completeness, reflow those connections as well.

73,
Don W3FPR

On 6/2/2012 4:24 PM, VK1OO wrote:

> Don,
>
> The effect happens when the antenna is disconnected as well as when
> connected.
> And in SBB and CW
>
> SSB Filter Widths
> X1 = OP1
> X2 = 2.4
> X3 = 2.1
> X4 = 1.8
>
> CW Filter Widths
> X1 = OP1
> X2 = 0.7
> X3 = 0.4
> X4 = 0.1
>
> I assume something is going wrong in the 4.915MHz Variable Bandwidth
> Crystal Filter.
>
>

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

Don,

Thanks. I reflowed the RF board components without any improvement. So
onto the KSB2 next.

Mike

On 03-Jun-12 6:59 AM, Don Wilhelm wrote:

> Mike,
>
> If you do not find the solution re-flowing the solder on the RF board
> filter area, the problem source may be on the KSB2 board in the
> switching diodes and/or resistors at the filter end of that board, so
> for completeness, reflow those connections as well.
>
> 73,
> Don W3FPR
>
> On 6/2/2012 4:24 PM, VK1OO wrote:
>> Don,
>>
>> The effect happens when the antenna is disconnected as well as when
>> connected.
>> And in SBB and CW
>>
>> SSB Filter Widths
>> X1 = OP1
>> X2 = 2.4
>> X3 = 2.1
>> X4 = 1.8
>>
>> CW Filter Widths
>> X1 = OP1
>> X2 = 0.7
>> X3 = 0.4
>> X4 = 0.1
>>
>> I assume something is going wrong in the 4.915MHz Variable Bandwidth
>> Crystal Filter.
>>
>>
>

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

In reply to this post by Don Wilhelm-4

Hi Don,

We have a long weekend here, so I've been able to get back to this.
I reflowed RF board and KSB2 board, with no improvement.

I then took out the KSB2, inserting the previously removed links and the
capacitor (effectively returning radio to pre-KSB2 state). The noise
problem on X1 goes away.

Your thoughts on what to look at next would be appreciated.

Mike
VK1OO

On 03-Jun-12 6:59 AM, Don Wilhelm wrote:

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

Mike,

It is on the KSB2 board somewhere. Check everything on the end of that
board containing the filter crystals. Check T1 and T2 to be certain all
the leads are well stripped, tinned and soldered and be sure there are
no shorted turns on those toroids. I recently repaired a K2 that had
the shorted turn problem because the builder use a flame to burn off the
insulation from the toroid wires and got too much flame on the red T2
wires when he tried to strip the green leads.

73,
Don W3FPR

On 6/9/2012 7:29 PM, VK1OO wrote:

> Hi Don,
>
> We have a long weekend here, so I've been able to get back to this.
> I reflowed RF board and KSB2 board, with no improvement.
>
> I then took out the KSB2, inserting the previously removed links and
> the capacitor (effectively returning radio to pre-KSB2 state). The
> noise problem on X1 goes away.
>
> Your thoughts on what to look at next would be appreciated.
>
> Mike
> VK1OO
>
>
> On 03-Jun-12 6:59 AM, Don Wilhelm wrote:
>> Mike,
>>
>> If you do not find the solution re-flowing the solder on the RF board
>> filter area, the problem source may be on the KSB2 board in the
>> switching diodes and/or resistors at the filter end of that board, so
>> for completeness, reflow those connections as well.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/2/2012 4:24 PM, VK1OO wrote:
>>> Don,
>>>
>>> The effect happens when the antenna is disconnected as well as when
>>> connected.
>>> And in SBB and CW
>>>
>>> SSB Filter Widths
>>> X1 = OP1
>>> X2 = 2.4
>>> X3 = 2.1
>>> X4 = 1.8
>>>
>>> CW Filter Widths
>>> X1 = OP1
>>> X2 = 0.7
>>> X3 = 0.4
>>> X4 = 0.1
>>>
>>> I assume something is going wrong in the 4.915MHz Variable Bandwidth
>>> Crystal Filter.
>>>
>>>
>>
>

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

Don,

Still no joy with this problem. I've resoldered most of the joints on
the KSB2, checked the torroids etc and have gone back and checked the
filters with a noise generator and spectrogram.
What feature of the circuit would account for the increase in S meter bars?

Mike
VK1OO

On 10-Jun-12 10:12 AM, Don Wilhelm wrote:

> Mike,
>
> Two different filters - the FL1 OP1 filter is the one on the KSB2
> board while the others are created from the variable bandwidth filter
> on the RF board. Since all but OP1 work correctly, it has to be the
> OP1 filter on the KSB2 board.
>
> Oh, one more piece of info - when you remove the KSB2 board, the OP1
> filter goes away, and the filtering defaults to a 2.20 bandwidth
> filter from the filter on the RF Board.
>
> 73,
> Don W3FPR
>
> On 6/9/2012 7:54 PM, VK1OO wrote:
>> Hi Don,
>>
>> Wow, thanks for fast response noting it must be late there.
>>
>> I will do. What conclusion can be drawn from X1 being affected, and
>> not X2-4?
>>
>> Mike
>> VK1OO
>>
>> On 10-Jun-12 9:43 AM, Don Wilhelm wrote:
>>> Mike,
>>>
>>> It is on the KSB2 board somewhere. Check everything on the end of
>>> that board containing the filter crystals. Check T1 and T2 to be
>>> certain all the leads are well stripped, tinned and soldered and be
>>> sure there are no shorted turns on those toroids. I recently
>>> repaired a K2 that had the shorted turn problem because the builder
>>> use a flame to burn off the insulation from the toroid wires and got
>>> too much flame on the red T2 wires when he tried to strip the green
>>> leads.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 6/9/2012 7:29 PM, VK1OO wrote:
>>>> Hi Don,
>>>>
>>>> We have a long weekend here, so I've been able to get back to this.
>>>> I reflowed RF board and KSB2 board, with no improvement.
>>>>
>>>> I then took out the KSB2, inserting the previously removed links
>>>> and the capacitor (effectively returning radio to pre-KSB2 state).
>>>> The noise problem on X1 goes away.
>>>>
>>>> Your thoughts on what to look at next would be appreciated.
>>>>
>>>> Mike
>>>> VK1OO
>>>>
>>>>
>>>> On 03-Jun-12 6:59 AM, Don Wilhelm wrote:
>>>>> Mike,
>>>>>
>>>>> If you do not find the solution re-flowing the solder on the RF
>>>>> board filter area, the problem source may be on the KSB2 board in
>>>>> the switching diodes and/or resistors at the filter end of that
>>>>> board, so for completeness, reflow those connections as well.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>> On 6/2/2012 4:24 PM, VK1OO wrote:
>>>>>> Don,
>>>>>>
>>>>>> The effect happens when the antenna is disconnected as well as when
>>>>>> connected.
>>>>>> And in SBB and CW
>>>>>>
>>>>>> SSB Filter Widths
>>>>>> X1 = OP1
>>>>>> X2 = 2.4
>>>>>> X3 = 2.1
>>>>>> X4 = 1.8
>>>>>>
>>>>>> CW Filter Widths
>>>>>> X1 = OP1
>>>>>> X2 = 0.7
>>>>>> X3 = 0.4
>>>>>> X4 = 0.1
>>>>>>
>>>>>> I assume something is going wrong in the 4.915MHz Variable Bandwidth
>>>>>> Crystal Filter.
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599

Don Wilhelm-4

Re: Help - K2 Higher Noise Level with X1 Selected

Mike,

OK, back up a step and look at the amplitude of the passband when using
Spectrogram.
The OP1 filter and the other filters should have close to the same
amplitude when the K2 is fed with a broadband noise generator.

Please verify for that condition.

73,
Don W3FPR

On 6/17/2012 7:04 AM, VK1OO wrote:

> Don,
>
> Still no joy with this problem. I've resoldered most of the joints on
> the KSB2, checked the torroids etc and have gone back and checked the
> filters with a noise generator and spectrogram.
> What feature of the circuit would account for the increase in S meter bars?
>
> Mike
> VK1OO
>
>
> On 10-Jun-12 10:12 AM, Don Wilhelm wrote:
>> Mike,
>>
>> Two different filters - the FL1 OP1 filter is the one on the KSB2
>> board while the others are created from the variable bandwidth filter
>> on the RF board. Since all but OP1 work correctly, it has to be the
>> OP1 filter on the KSB2 board.
>>
>> Oh, one more piece of info - when you remove the KSB2 board, the OP1
>> filter goes away, and the filtering defaults to a 2.20 bandwidth
>> filter from the filter on the RF Board.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/9/2012 7:54 PM, VK1OO wrote:
>>> Hi Don,
>>>
>>> Wow, thanks for fast response noting it must be late there.
>>>
>>> I will do. What conclusion can be drawn from X1 being affected, and
>>> not X2-4?
>>>
>>> Mike
>>> VK1OO
>>>
>>> On 10-Jun-12 9:43 AM, Don Wilhelm wrote:
>>>> Mike,
>>>>
>>>> It is on the KSB2 board somewhere. Check everything on the end of
>>>> that board containing the filter crystals. Check T1 and T2 to be
>>>> certain all the leads are well stripped, tinned and soldered and be
>>>> sure there are no shorted turns on those toroids. I recently
>>>> repaired a K2 that had the shorted turn problem because the builder
>>>> use a flame to burn off the insulation from the toroid wires and got
>>>> too much flame on the red T2 wires when he tried to strip the green
>>>> leads.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> On 6/9/2012 7:29 PM, VK1OO wrote:
>>>>> Hi Don,
>>>>>
>>>>> We have a long weekend here, so I've been able to get back to this.
>>>>> I reflowed RF board and KSB2 board, with no improvement.
>>>>>
>>>>> I then took out the KSB2, inserting the previously removed links
>>>>> and the capacitor (effectively returning radio to pre-KSB2 state).
>>>>> The noise problem on X1 goes away.
>>>>>
>>>>> Your thoughts on what to look at next would be appreciated.
>>>>>
>>>>> Mike
>>>>> VK1OO
>>>>>
>>>>>
>>>>> On 03-Jun-12 6:59 AM, Don Wilhelm wrote:
>>>>>> Mike,
>>>>>>
>>>>>> If you do not find the solution re-flowing the solder on the RF
>>>>>> board filter area, the problem source may be on the KSB2 board in
>>>>>> the switching diodes and/or resistors at the filter end of that
>>>>>> board, so for completeness, reflow those connections as well.
>>>>>>
>>>>>> 73,
>>>>>> Don W3FPR
>>>>>>
>>>>>> On 6/2/2012 4:24 PM, VK1OO wrote:
>>>>>>> Don,
>>>>>>>
>>>>>>> The effect happens when the antenna is disconnected as well as when
>>>>>>> connected.
>>>>>>> And in SBB and CW
>>>>>>>
>>>>>>> SSB Filter Widths
>>>>>>> X1 = OP1
>>>>>>> X2 = 2.4
>>>>>>> X3 = 2.1
>>>>>>> X4 = 1.8
>>>>>>>
>>>>>>> CW Filter Widths
>>>>>>> X1 = OP1
>>>>>>> X2 = 0.7
>>>>>>> X3 = 0.4
>>>>>>> X4 = 0.1
>>>>>>>
>>>>>>> I assume something is going wrong in the 4.915MHz Variable Bandwidth
>>>>>>> Crystal Filter.
>>>>>>>
>>>>>>>
> ______________________________________________________________
> 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
>

VK1OO, Mike Walkington

Re: Help - K2 Higher Noise Level with X1 Selected

Hi Don,

As usual, thanks for your assistance. Pulling seven crystals with no
super confidence that that's the problem seems hard work. How often
does a crystal die? I've not had that fault before in any of my equipment.

I have an XG3 sig gen (known level) and access to a CRO. Is there any
level testing comparison I can do to get a sense of where the problem is?
Is there a matrix describing switching paths with their inputs and
outputs? If not, could you describe the area of the circuit I need to
look at and understand. Seems like I need some way of stepping through
the combinations and confirming they work / finding what doesn't.

Cheers
Mike

On 25-Jun-12 6:20 AM, Don Wilhelm wrote:

> Mike,
>
> I can see that, but unfortunately, it does not help with the isolation
> of the problem.
> Ome easy thing you could do is assume a bad crystal in the set on the
> base K2 board and try replacing the 7 crystals. If I were to make a
> first guess, that would be what I would do.
>
> OTOH, there may be a problem with the switching path through the KSB2
> diodes that change the path for the two filters. Since you have
> already checked the diodes for orientation, that is not as likely as a
> faulty crystal.
>
> 73,
> Don W3FPR
>
> On 6/23/2012 3:09 AM, VK1OO wrote:
>> Hi Don,
>>
>> I've attached a ppt showing FL1-FL4 (Slide 1-Slide 4) responses to
>> broadband noise. I could send separate jpg if necessary.
>>
>> You can see the reduction in signal (audio) between FL1, and FL2-4.
>> FL1 sounds louder and has the extra three S Meter bars.
>>
>> Mike
>>
>>
>>
>> On 17-Jun-12 10:19 PM, Don Wilhelm wrote:
>>> Mike,
>>>
>>>
>>>
>>>
>>>
>>> OK, back up a step and look at the amplitude of the passband when
>>> using Spectrogram.
>>> The OP1 filter and the other filters should have close to the same
>>> amplitude when the K2 is fed with a broadband noise generator.
>>>
>>> Please verify for that condition.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 6/17/2012 7:04 AM, VK1OO wrote:
>>>> Don,
>>>>
>>>> Still no joy with this problem. I've resoldered most of the joints on
>>>> the KSB2, checked the torroids etc and have gone back and checked the
>>>> filters with a noise generator and spectrogram.
>>>> What feature of the circuit would account for the increase in S
>>>> meter bars?
>>>>
>>>> Mike
>>>> VK1OO
>>>>
>>>>
>>>> On 10-Jun-12 10:12 AM, Don Wilhelm wrote:
>>>>> Mike,
>>>>>
>>>>> Two different filters - the FL1 OP1 filter is the one on the KSB2
>>>>> board while the others are created from the variable bandwidth filter
>>>>> on the RF board. Since all but OP1 work correctly, it has to be the
>>>>> OP1 filter on the KSB2 board.
>>>>>
>>>>> Oh, one more piece of info - when you remove the KSB2 board, the OP1
>>>>> filter goes away, and the filtering defaults to a 2.20 bandwidth
>>>>> filter from the filter on the RF Board.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>> On 6/9/2012 7:54 PM, VK1OO wrote:
>>>>>> Hi Don,
>>>>>>
>>>>>> Wow, thanks for fast response noting it must be late there.
>>>>>>
>>>>>> I will do. What conclusion can be drawn from X1 being affected, and
>>>>>> not X2-4?
>>>>>>
>>>>>> Mike
>>>>>> VK1OO
>>>>>>
>>>>>> On 10-Jun-12 9:43 AM, Don Wilhelm wrote:
>>>>>>> Mike,
>>>>>>>
>>>>>>> It is on the KSB2 board somewhere. Check everything on the end of
>>>>>>> that board containing the filter crystals. Check T1 and T2 to be
>>>>>>> certain all the leads are well stripped, tinned and soldered
>>>>>>> and be
>>>>>>> sure there are no shorted turns on those toroids. I recently
>>>>>>> repaired a K2 that had the shorted turn problem because the builder
>>>>>>> use a flame to burn off the insulation from the toroid wires and
>>>>>>> got
>>>>>>> too much flame on the red T2 wires when he tried to strip the green
>>>>>>> leads.
>>>>>>>
>>>>>>> 73,
>>>>>>> Don W3FPR
>>>>>>>
>>>>>>> On 6/9/2012 7:29 PM, VK1OO wrote:
>>>>>>>> Hi Don,
>>>>>>>>
>>>>>>>> We have a long weekend here, so I've been able to get back to
>>>>>>>> this.
>>>>>>>> I reflowed RF board and KSB2 board, with no improvement.
>>>>>>>>
>>>>>>>> I then took out the KSB2, inserting the previously removed links
>>>>>>>> and the capacitor (effectively returning radio to pre-KSB2 state).
>>>>>>>> The noise problem on X1 goes away.
>>>>>>>>
>>>>>>>> Your thoughts on what to look at next would be appreciated.
>>>>>>>>
>>>>>>>> Mike
>>>>>>>> VK1OO
>>>>>>>>
>>>>>>>>
>>>>>>>> On 03-Jun-12 6:59 AM, Don Wilhelm wrote:
>>>>>>>>> Mike,
>>>>>>>>>
>>>>>>>>> If you do not find the solution re-flowing the solder on the RF
>>>>>>>>> board filter area, the problem source may be on the KSB2 board in
>>>>>>>>> the switching diodes and/or resistors at the filter end of that
>>>>>>>>> board, so for completeness, reflow those connections as well.
>>>>>>>>>
>>>>>>>>> 73,
>>>>>>>>> Don W3FPR
>>>>>>>>>
>>>>>>>>> On 6/2/2012 4:24 PM, VK1OO wrote:
>>>>>>>>>> Don,
>>>>>>>>>>
>>>>>>>>>> The effect happens when the antenna is disconnected as well
>>>>>>>>>> as when
>>>>>>>>>> connected.
>>>>>>>>>> And in SBB and CW
>>>>>>>>>>
>>>>>>>>>> SSB Filter Widths
>>>>>>>>>> X1 = OP1
>>>>>>>>>> X2 = 2.4
>>>>>>>>>> X3 = 2.1
>>>>>>>>>> X4 = 1.8
>>>>>>>>>>
>>>>>>>>>> CW Filter Widths
>>>>>>>>>> X1 = OP1
>>>>>>>>>> X2 = 0.7
>>>>>>>>>> X3 = 0.4
>>>>>>>>>> X4 = 0.1
>>>>>>>>>>
>>>>>>>>>> I assume something is going wrong in the 4.915MHz Variable
>>>>>>>>>> Bandwidth
>>>>>>>>>> Crystal Filter.
>>>>>>>>>>
>>>>>>>>>>
>>>> ______________________________________________________________
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>>>>
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>>>
>>>
>>>
>
>
>

Cheers
Mike
VK1OO (ex AC7MZ, VK1KCK)
K2: 2599