K60XV Low Voltage in VCO Alignment

[Brian Broggie]

Haven't seen this problem lately...

I am adding the K60XV option to a K2.  During the VCO alignment the 60M
level is waaay down, ranging from 0.8vdc to 1.2vdc; far below spec.  All
other bands are fine.  Visually verified the usual suspects (D19, D20,
C71) are installed correctly.

Troubleshooting ideas are welcome.

--
73,
Brian - W6FVI


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[Don Wilhelm-3]

Brian,

You did change C71 to 120 pF did you not?  C73 is also a suspect, check that
it is 47 pf.

What voltage do you get at 4 MHz?  It will normally be in the 6 to 7 volt
range when everything is proper.  If relay K13 is properly operating and the
capacitors are the correct value, things should fall in line.

How low are you trying to tune on the 60 meter band?  If you are checking at
5000 MHz, what you are seeing is normal.  Check at 5300 kHz as the low end.
The allowable voltage range with the K60XV added is 1.0 volts to 7.5 volts,
and you are not that far out of range with 0.8 volts (yes, the 60 meter band
is usually higher than that, and I try for about 0.8 to 1 volt at 5000 kHz).
It may only be necessary to shift the entire range a bit.

If the voltage is low, there is not enough capacity in the VCO circuit to
produce the frequency that is needed.  You may want to look at the
freequency with the counter probe and CAL FCTR to see how the frequency
compares with the VCO table on the Schematic Key sheet of Appendix B.

73,
Don W3FPR

> -----Original Message-----
>
> Haven't seen this problem lately...
>
> I am adding the K60XV option to a K2.  During the VCO alignment the 60M
> level is waaay down, ranging from 0.8vdc to 1.2vdc; far below spec.  All
> other bands are fine.  Visually verified the usual suspects (D19, D20,
> C71) are installed correctly.
>
> Troubleshooting ideas are welcome.
>
> --
> 73,
> Brian - W6FVI
>
>

--
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Version: 7.0.344 / Virus Database: 267.11.10/119 - Release Date: 10/4/2005

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[Brian Broggie]

Thanks, Don!

My K60XV is now working.  The best tip you gave me was the CAL FCTR vs.
the VCO table on the lower 60M band edge.  When I found the frequency
was extremely close, I decided to try your suggestion of shifting all
the VCO voltages up by adjusting L30.  I adjusted L30 while tuned to
5300 until the R30 voltage rose up to 1.00VDC.  After that, all the
other band voltages at R30 were checked and still measured within spec.

Thanks for your typically excellent advice!

73,
Brian Broggie - W6FVI
Elecraft Parts



W3FPR - Don Wilhelm wrote:

>Brian,
>
>You did change C71 to 120 pF did you not?  C73 is also a suspect, check that
>it is 47 pf.
>
>What voltage do you get at 4 MHz?  It will normally be in the 6 to 7 volt
>range when everything is proper.  If relay K13 is properly operating and the
>capacitors are the correct value, things should fall in line.
>
>How low are you trying to tune on the 60 meter band?  If you are checking at
>5000 MHz, what you are seeing is normal.  Check at 5300 kHz as the low end.
>The allowable voltage range with the K60XV added is 1.0 volts to 7.5 volts,
>and you are not that far out of range with 0.8 volts (yes, the 60 meter band
>is usually higher than that, and I try for about 0.8 to 1 volt at 5000 kHz).
>It may only be necessary to shift the entire range a bit.
>
>If the voltage is low, there is not enough capacity in the VCO circuit to
>produce the frequency that is needed.  You may want to look at the
>freequency with the counter probe and CAL FCTR to see how the frequency
>compares with the VCO table on the Schematic Key sheet of Appendix B.
>
>73,
>Don W3FPR
>
>  
>
>>-----Original Message-----
>>
>>Haven't seen this problem lately...
>>
>>I am adding the K60XV option to a K2.  During the VCO alignment the 60M
>>level is waaay down, ranging from 0.8vdc to 1.2vdc; far below spec.  All
>>other bands are fine.  Visually verified the usual suspects (D19, D20,
>>C71) are installed correctly.
>>
>>Troubleshooting ideas are welcome.
>>
>>--
>>73,
>>Brian - W6FVI
>>
>>
>>    
>>
>--
>No virus found in this outgoing message.
>Checked by AVG Anti-Virus.
>Version: 7.0.344 / Virus Database: 267.11.10/119 - Release Date: 10/4/2005
>  
>

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