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K2 Alignment & Test Part II

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Neil Zampella

K2 Alignment & Test Part II

Hi,

Started to do the Align/Test Pt II, and properly saw the correct
frequency of 12090 +/- 30 kHz.   Tried the next part to adjust the
Reference Oscillator using my other K2 as the receiver and was able to
hear the oscillator at 3999, but C22 would not adjust to a
zero-beat.     OK ... so it was close for the time being, so I figured
I'd use my KX3 to verify it later. Moved on to the range test.   The
Band- and Band+ buttons did not affect the display.

Dug into the list archives, and saw a number of messages from Don to
check the solder joints, alignment, and type of D16, D17, R19, and
L31.    I realized that somehow I missed installing R19.   So I
installed the resistor, then restarted the alignment.   This time when I
switched to CAL FCTR, the rig did not display the expected frequency of
12090, but a frequency of 3560 or so, flickering between readings.
However, when I pressed the Band- button, it changed to a steady 12084,
but when the Band+ was pressed, back to the 3560 flickering.

I checked the other areas as referenced by Don such as the thermistor,
but did not see any issues such as solder bridges, etc.   I really do
not want to remove the thermistor board to check closer, but will if
there are no resistance or voltage readings I could use to verify that
its OK.     I did verify the voltage readings as referenced by Don in
another message and they were within expected.

That said, I am rather limited in test equipment, with just a good
digital multimeter, so I can't put things on a scope, etc.    Any hints
would be appreciated, I can say I'm very sure I did not put any of the
ICs in backwards, I learned that the hard way when building my K2/100.

Merry Christmas to all, and a Happy New Year.

Neil, KN3ILZ

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Don Wilhelm

Re: K2 Alignment & Test Part II

Neil,

Your readings on the PLL range test show that Q19 is marginal. Q19 is
not oscillating properly at the high end of the PLL range.

The first thing to try is a small capacitor (12 to 15pF) from the source
of Q19 to ground. You can easily mount the capacitor between pins 1 and
12 of U4. You can use one of the capacitors from the K2 kit and request
a replacement from [hidden email]

If that does not allow proper frequencies for the PLL Range Test, then
get a replacement Q19 from [hidden email].

Merry Christmas everyone.

73,
Don W3FPR

On 12/24/2019 6:19 PM, Neil Zampella wrote:

> Hi,
>
> Started to do the Align/Test Pt II, and properly saw the correct
> frequency of 12090 +/- 30 kHz.   Tried the next part to adjust the
> Reference Oscillator using my other K2 as the receiver and was able to
> hear the oscillator at 3999, but C22 would not adjust to a
> zero-beat.     OK ... so it was close for the time being, so I figured
> I'd use my KX3 to verify it later. Moved on to the range test.   The
> Band- and Band+ buttons did not affect the display.
>
> Dug into the list archives, and saw a number of messages from Don to
> check the solder joints, alignment, and type of D16, D17, R19, and
> L31.    I realized that somehow I missed installing R19.   So I
> installed the resistor, then restarted the alignment.   This time when I
> switched to CAL FCTR, the rig did not display the expected frequency of
> 12090, but a frequency of 3560 or so, flickering between readings.
> However, when I pressed the Band- button, it changed to a steady 12084,
> but when the Band+ was pressed, back to the 3560 flickering.
>

______________________________________________________________
Elecraft mailing list
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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
Message delivered to [hidden email]

Neil Zampella

Re: K2 Alignment & Test Part II

Don,

Thanks, I'll work on that tomorrow and let you know how it goes.

Merry Christmas!!

Neil

On 12/25/2019 11:19 AM, Don Wilhelm wrote:

> Neil,
>
> Your readings on the PLL range test show that Q19 is marginal. Q19 is
> not oscillating properly at the high end of the PLL range.
>
> The first thing to try is a small capacitor (12 to 15pF) from the
> source of Q19 to ground. You can easily mount the capacitor between
> pins 1 and 12 of U4. You can use one of the capacitors from the K2
> kit and request a replacement from [hidden email]
>
> If that does not allow proper frequencies for the PLL Range Test, then
> get a replacement Q19 from [hidden email].
>
> Merry Christmas everyone.
>
> 73,
> Don W3FPR
>
> On 12/24/2019 6:19 PM, Neil Zampella wrote:
>> Hi,
>>
>> Started to do the Align/Test Pt II, and properly saw the correct
>> frequency of 12090 +/- 30 kHz.   Tried the next part to adjust the
>> Reference Oscillator using my other K2 as the receiver and was able to
>> hear the oscillator at 3999, but C22 would not adjust to a
>> zero-beat.     OK ... so it was close for the time being, so I figured
>> I'd use my KX3 to verify it later. Moved on to the range test.   The
>> Band- and Band+ buttons did not affect the display.
>>
>> Dug into the list archives, and saw a number of messages from Don to
>> check the solder joints, alignment, and type of D16, D17, R19, and
>> L31.    I realized that somehow I missed installing R19.   So I
>> installed the resistor, then restarted the alignment.   This time when I
>> switched to CAL FCTR, the rig did not display the expected frequency of
>> 12090, but a frequency of 3560 or so, flickering between readings.
>> However, when I pressed the Band- button, it changed to a steady 12084,
>> but when the Band+ was pressed, back to the 3560 flickering.
>>
>

Neil Zampella

Re: K2 Alignment & Test Part II

Don,

I installed the 12pF cap as suggested didn't help, so I'm going to
request a replacement Q19.

Thanks,

Neil, KN3ILZ

On 12/25/2019 3:24 PM, Neil Zampella wrote:

> Don,
>
> Thanks, I'll work on that tomorrow and let you know how it goes.
>
> Merry Christmas!!
>
> Neil
>
> On 12/25/2019 11:19 AM, Don Wilhelm wrote:
>> Neil,
>>
>> Your readings on the PLL range test show that Q19 is marginal. Q19 is
>> not oscillating properly at the high end of the PLL range.
>>
>> The first thing to try is a small capacitor (12 to 15pF) from the
>> source of Q19 to ground. You can easily mount the capacitor between
>> pins 1 and 12 of U4. You can use one of the capacitors from the K2
>> kit and request a replacement from [hidden email]
>>
>> If that does not allow proper frequencies for the PLL Range Test,
>> then get a replacement Q19 from [hidden email].
>>
>> Merry Christmas everyone.
>>
>> 73,
>> Don W3FPR
>>
>> On 12/24/2019 6:19 PM, Neil Zampella wrote:
>>> Hi,
>>>
>>> Started to do the Align/Test Pt II, and properly saw the correct
>>> frequency of 12090 +/- 30 kHz.   Tried the next part to adjust the
>>> Reference Oscillator using my other K2 as the receiver and was able to
>>> hear the oscillator at 3999, but C22 would not adjust to a
>>> zero-beat.     OK ... so it was close for the time being, so I figured
>>> I'd use my KX3 to verify it later. Moved on to the range test.   The
>>> Band- and Band+ buttons did not affect the display.
>>>
>>> Dug into the list archives, and saw a number of messages from Don to
>>> check the solder joints, alignment, and type of D16, D17, R19, and
>>> L31.    I realized that somehow I missed installing R19.   So I
>>> installed the resistor, then restarted the alignment.   This time
>>> when I
>>> switched to CAL FCTR, the rig did not display the expected frequency of
>>> 12090, but a frequency of 3560 or so, flickering between readings.
>>> However, when I pressed the Band- button, it changed to a steady 12084,
>>> but when the Band+ was pressed, back to the 3560 flickering.
>>>
>>