K3 Hardware Upgrades

[Don Rasmussen]

I did upgrades today for early K3 #272.

I considered these necessary:
12v sense PA
REMIO UPGD RS232 isolation
and AFOPMDKT speaker short circuit protection.

I also ordered a new top cover to match the beautiful textured
top cover Elecraft is sending with new K3s. The sides and bottom
seem the same, already textured. And for some odd reason the side
panels are even more expensive than the top. ???

I did -not- apply the AF Stage upgrade for LINE OUT and speaker
can anyone suggest that there is a perceptable difference to be heard with this?  

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[Jim Brown-10]

On Fri, 13 Mar 2009 12:11:28 -0700 (PDT), Don Rasmussen wrote:


>I did -not- apply the AF Stage upgrade for LINE OUT and speaker
>can anyone suggest that there is a perceptable difference to be
>heard with this

I have not done it yet, but from the description, it should solve
the distortion problem on the Line Out, which I consider serious if
you use the line output. Most of us use it to feed the sound card
for data modes.  

73,

Jim K9YC


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[Dave, G4AON]

I have now done all the hardware mods to my K3, none were particularly
difficult to do. I even did modifications that are of no use to me, such
as the -ve ALC and "pull up" resistor mods... At least my K3 is close to
the same mod state as the current production units. The AF amplifier
(replacement RF choke feeding the audio amp) did not seem to make any
difference at my station, I am using a pair of HiFi bookshelf speakers.
Likewise the line out mod didn't appear to make any difference, although
for the most part I run Amtor or Pactor rather than sound card data modes.

There is no real reason to not do these mods, they have no unwanted side
effects and may in fact be of benefit.

73 Dave, G4AON
K3/100 #80
-----------------
I did -not- apply the AF Stage upgrade for LINE OUT and speaker
can anyone suggest that there is a perceptable difference to be heard
with this?
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[David Pratt]

Although I don't recall seeing anything about it on here, the latest
KRX3 Errata Sheet C-6, dated 3 March 2009 refers to the cutting of two
tracks on the main RF board to "ensure D-A converters always receive the
proper signal level".

I have yet to do this mod on my K3.

73

David

In a recent message, Dave G4AON <[hidden email]> writes

>
>I have now done all the hardware mods to my K3, none were particularly
>difficult to do. I even did modifications that are of no use to me, such
>as the -ve ALC and "pull up" resistor mods... At least my K3 is close to
>the same mod state as the current production units. The AF amplifier
>(replacement RF choke feeding the audio amp) did not seem to make any
>difference at my station, I am using a pair of HiFi bookshelf speakers.
>Likewise the line out mod didn't appear to make any difference, although
>for the most part I run Amtor or Pactor rather than sound card data modes.
>
>There is no real reason to not do these mods, they have no unwanted side
>effects and may in fact be of benefit.

--
David G4DMP
Leeds, England, UK


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[alsopb]

Natural questions:
1) What are symptoms of them not being cut?
2)  About what vintage main RF board are they not cut?

At least it looks easy to get to.

73 de Brian/K3KO

David Pratt wrote:

>Although I don't recall seeing anything about it on here, the latest
>KRX3 Errata Sheet C-6, dated 3 March 2009 refers to the cutting of two
>tracks on the main RF board to "ensure D-A converters always receive the
>proper signal level".
>
>I have yet to do this mod on my K3.
>
>73
>
>David
>
>In a recent message, Dave G4AON <[hidden email]> writes
>  
>
>>I have now done all the hardware mods to my K3, none were particularly
>>difficult to do. I even did modifications that are of no use to me, such
>>as the -ve ALC and "pull up" resistor mods... At least my K3 is close to
>>the same mod state as the current production units. The AF amplifier
>>(replacement RF choke feeding the audio amp) did not seem to make any
>>difference at my station, I am using a pair of HiFi bookshelf speakers.
>>Likewise the line out mod didn't appear to make any difference, although
>>for the most part I run Amtor or Pactor rather than sound card data modes.
>>
>>There is no real reason to not do these mods, they have no unwanted side
>>effects and may in fact be of benefit.
>>    
>>

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[Mike Harris-9]

G'day,

Spot on.  This is the sort of information that should be released to the
list direct from source, not discovered by accident.

Regards,

Mike VP8NO

----- Original Message -----
From: "Brian Alsop" <[hidden email]>
Cc: <[hidden email]>
Sent: Friday, March 13, 2009 8:14 PM
Subject: Re: [Elecraft] K3 Hardware Upgrades


| Natural questions:
| 1) What are symptoms of them not being cut?
| 2)  About what vintage main RF board are they not cut?
|
| At least it looks easy to get to.
|
| 73 de Brian/K3KO
|
| David Pratt wrote:
|
| >Although I don't recall seeing anything about it on here, the latest
| >KRX3 Errata Sheet C-6, dated 3 March 2009 refers to the cutting of two
| >tracks on the main RF board to "ensure D-A converters always receive
the
| >proper signal level".
| >
| >I have yet to do this mod on my K3.
| >
| >73
| >
| >David

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[gm3sek]

David Pratt wrote:

>In a recent message, Dave G4AON <[hidden email]> writes
>>
>>I have now done all the hardware mods to my K3, none were particularly
>>difficult to do. I even did modifications that are of no use to me, such
>>as the -ve ALC and "pull up" resistor mods... At least my K3 is close to
>>the same mod state as the current production units. The AF amplifier
>>(replacement RF choke feeding the audio amp) did not seem to make any
>>difference at my station, I am using a pair of HiFi bookshelf speakers.
>>Likewise the line out mod didn't appear to make any difference, although
>>for the most part I run Amtor or Pactor rather than sound card data modes.
>>
>>There is no real reason to not do these mods, they have no unwanted side
>>effects and may in fact be of benefit.

>Although I don't recall seeing anything about it on here, the latest
>KRX3 Errata Sheet C-6, dated 3 March 2009 refers to the cutting of two
>tracks on the main RF board to "ensure D-A converters always receive the
>proper signal level".
>
>I have yet to do this mod on my K3.


Those track cuts were part of the negative ALC mod, and according to the
website, that is now "Included on all K3s shipped on Dec 10, 2008 and
later.... Approx s/n 2362+ "

Presumably that also includes the track cuts, but it's easy enough to
check - they are in clear view underneath the front bottom cover.

The ALC mod sheet gave no specific reason for cutting the tracks, and it
seems very odd that the same track cuts should appear again in an errata
sheet for KRX3 installation - the two topics seem totally unrelated.




--

73 from Ian GM3SEK
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