Elecraft

Re: Elecraft Digest, Vol 31, Issue 3

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Cathy James

Re: Elecraft Digest, Vol 31, Issue 3

[hidden email] wrote:

> The K2 has a series
> diode in the power supply line for reverse polarity protection - that diode
> drops about .2 volts.
>
> What that means is: to obtain 13.8 volts at the battery terminals, one must
> connect a supply of 14.0 volts to the K2 to maintain full charge on the
> battery.
>
> There is an intenal pot in the Astron to adjust the output voltage, so it
> may be a simple matter to increase the Astron voltage - locating the correct
> pot may be more of a challenge, be certain you adjust the proper pot.
>
> 73,
> Don W3FPR
>

I adjusted my Astron to 14.1V output using the internal pot, but be
warned that it is a semi-major project. The pot is on the underside of
the small floating board IIRC; every time I wanted to adjust it, I had
to short out the large electrolytic capacitor in the Astron, unscrew the
board, pull it up, make a guess as to how much to adjust it, screw it
back down, power up the supply, check the voltage, see that it's still
wrong, power down, short out the cap, unscrew the board....

There may be an easier way to do it but it wasn't obvious. I'd guess
that it took me a dozen iterations. I don't ever want to mess with it
again.

What was Astron thinking burying the pot where it can't be safely and
readily accessed just by removing the cover???

Cathy
N5WVR

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Tom Hammond-3

Re: Re: Elecraft Digest, Vol 31, Issue 3

Cathy:

For future possible adjustments... REMOVE the pot and reinstall it on
the SOLDER SIDE of the PC board... then it'll be on top where you can
easily access it! Saves a LOT OF HASSLE! And it's a SIMPLE one-time
task to perform.

If you do a lot of voltage adjustment (though few of us do), you
could always remove that PC-mount pot and replace it with a
chassis-mount pot (installed on the back of the case) attached to the
PC board via three wires.

73,

Tom N0SS

At 07:44 AM 11/3/2006, you wrote:

>[hidden email] wrote:
>>The K2 has a series
>>diode in the power supply line for reverse polarity protection - that diode
>>drops about .2 volts.
>>
>>What that means is: to obtain 13.8 volts at the battery terminals, one must
>>connect a supply of 14.0 volts to the K2 to maintain full charge on the
>>battery.
>>
>>There is an intenal pot in the Astron to adjust the output voltage, so it
>>may be a simple matter to increase the Astron voltage - locating the correct
>>pot may be more of a challenge, be certain you adjust the proper pot.
>>
>>73,
>>Don W3FPR
>>
>I adjusted my Astron to 14.1V output using the internal pot, but be
>warned that it is a semi-major project. The pot is on the underside
>of the small floating board IIRC; every time I wanted to adjust it,
>I had to short out the large electrolytic capacitor in the Astron,
>unscrew the board, pull it up, make a guess as to how much to adjust
>it, screw it back down, power up the supply, check the voltage, see
>that it's still wrong, power down, short out the cap, unscrew the board....
>
>There may be an easier way to do it but it wasn't obvious. I'd
>guess that it took me a dozen iterations. I don't ever want to mess
>with it again.
>
>What was Astron thinking burying the pot where it can't be safely
>and readily accessed just by removing the cover???
>
>Cathy
>N5WVR
>
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Cathy James

Re: Re: Elecraft Digest, Vol 31, Issue 3

Tom, that's a great idea,and it never occurred to me. However, it will
probably be years before I need to change the voltage again, so at this
point I doubt I'll bother. Thanks for the tip, though!

Cathy

Tom Hammond wrote:

> Cathy:
>
> For future possible adjustments... REMOVE the pot and reinstall it on
> the SOLDER SIDE of the PC board... then it'll be on top where you can
> easily access it! Saves a LOT OF HASSLE! And it's a SIMPLE one-time
> task to perform.
>
> If you do a lot of voltage adjustment (though few of us do), you could
> always remove that PC-mount pot and replace it with a chassis-mount
> pot (installed on the back of the case) attached to the PC board via
> three wires.
>
> 73,
>
> Tom N0SS
>
> At 07:44 AM 11/3/2006, you wrote:
>> [hidden email] wrote:
>>> The K2 has a series
>>> diode in the power supply line for reverse polarity protection -
>>> that diode
>>> drops about .2 volts.
>>>
>>> What that means is: to obtain 13.8 volts at the battery terminals,
>>> one must
>>> connect a supply of 14.0 volts to the K2 to maintain full charge on the
>>> battery.
>>>
>>> There is an intenal pot in the Astron to adjust the output voltage,
>>> so it
>>> may be a simple matter to increase the Astron voltage - locating the
>>> correct
>>> pot may be more of a challenge, be certain you adjust the proper pot.
>>>
>>> 73,
>>> Don W3FPR
>>>
>> I adjusted my Astron to 14.1V output using the internal pot, but be
>> warned that it is a semi-major project. The pot is on the underside
>> of the small floating board IIRC; every time I wanted to adjust it, I
>> had to short out the large electrolytic capacitor in the Astron,
>> unscrew the board, pull it up, make a guess as to how much to adjust
>> it, screw it back down, power up the supply, check the voltage, see
>> that it's still wrong, power down, short out the cap, unscrew the
>> board....
>>
>> There may be an easier way to do it but it wasn't obvious. I'd guess
>> that it took me a dozen iterations. I don't ever want to mess with
>> it again.
>>
>> What was Astron thinking burying the pot where it can't be safely and
>> readily accessed just by removing the cover???
>>
>> Cathy
>> N5WVR

N2EY

Re: Re: Elecraft Digest, Vol 31, Issue 3

In reply to this post by Cathy James

In a message dated 11/3/06 8:45:55 AM Eastern Standard Time,
[hidden email] writes:

> What was Astron thinking burying the pot where it can't be safely and
> readily accessed just by removing the cover???
>

They didn't want you to adjust it!

73 de Jim, N2EY
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Cathy James

Re: Re: Elecraft Digest, Vol 31, Issue 3

One thing I never want to see on any ham radio equipment: "No
user-serviceable parts inside."

Cathy, N5WVR

[hidden email] wrote:
> In a message dated 11/3/06 8:45:55 AM Eastern Standard Time,
> [hidden email] writes:
>> What was Astron thinking burying the pot where it can't be safely and
>> readily accessed just by removing the cover???
> They didn't want you to adjust it!
>
> 73 de Jim, N2EY

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Rick Dettinger-2

Re: Re: Elecraft Digest, Vol 31, Issue 3

One thing I never want to see on any ham radio equipment: "No
user-serviceable parts inside."

Cathy, N5WVR
============================================
That was one of several reasons I sold my TS850S in 2000 to buy a K2.
Another was that I didn't like the notion that Kenwood wanted me to send my
ham gear back to the factory to get the battery changed. And when I built a
QRP kit in 1998 (TenTec 1340) I found out what good QSK sounded like, and I
was never happy with the 850 again.
73
Rick Dettinger
K7MW

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