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List:       elecraft
Subject:    Re: [Elecraft] K2 - Need help drafting an Upgrade Plan for early K2/10
From:       Don Wilhelm <w3fpr () embarqmail ! com>
Date:       2013-07-30 1:55:03
Message-ID: 51F71CF7.9000404 () embarqmail ! com
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Dan,

Do *everything* ---  unless the prior owner has done some of the 
upgrades.  You can download the K2 A to B instructions to check if any 
mods have been applied to that K2.  With the firmware at 104/102, I 
doubt that any of the mods have been installed.

That means the A to B mods (yes, do all the optional ones).
Do the Alternate AF Gain Mod and replace the AG gain control.
Add the Extremely Strong Signal Handling diodes D40 and D41 (download 
the latest K2 manual to see where they go, there is no mod kit for that, 
just 2 1N4148 diodes).
Add the K2 CW Keying waveshape mod.  This mod kit is currently not 
available due to unavailability of the specified PIN diode, but if you 
want to add it, I can tell you what to order from Elecraft to make up 
the "kit on steroids" and help you with the other details - that mod is 
important for any K2 with the KPA100, important, but less so with the 
QRP K2.

Change the IF filter crystals on both the base K2 and the KSB2. While 
you have the crystals removed from the KSB2, change the filter 
capacitors to produce the 2.4 kHz width OP1 filter instead of the 2.1 
kHz width that is installed in your K2.

If this K2 has the KPA100, take a good look at the KPA100, it likely 
needs to be upgraded with the KPA100UPKT and the KPA100SHLDKT installed.

Be aware, that SN 100 was a Field Test serial number, and there are a 
few subtle differences between it and the REV A board that the mod 
instructions detail.  If you have any questions during your upgrade 
process, please ask, I am familiar with the Field Test boards - for one 
thing, when changing the crystals, do not discard the crystal 
insulators, re-use them on the new crystals.

I will be happy to assist you on your K2 upgrade journey or act as your 
"builder for hire".  When it is complete, your K2 will be as good as a 
new one off the line.  The single most expensive part of the upgrade is 
the firmware.

73,
Don W3FPR

On 7/29/2013 6:55 PM, Daniel J Tosh wrote:
> I have just acquired a very early (SN 100) K2 with the following 
> options..
> - KNB2 Noise Blanker
> - KBT2 Internal Battery (with dead battery)
> - KSB2 SSB Adapter
> - KAT2 Antenna Tuner
>
> Basically the radio seams to be working but with a few anomalies like..
> - AF Gain noise (sounds very much like what is described in the 
> "Alternative Wiring.." modification writeup)
> - CW all seems fine with about 12 watts out and "POWER" control works 
> as described.
> - On SSB the POWER control does not seem to vary the output power.
> - On 80 and 40 meters when transmitting SSB at most any power level 
> sometimes I get the HI CUR warning.
> - The frequency seems to be about 50 Hz off.
> - ATU seems to work fine.
>
> The radio came with a Kenwood Dynamic Hand Mic (800 ohm).  It also 
> seems to work but I have no way of knowing if it is the best fit for 
> the K2.
> As far as I can tell, no updates have been done to the radio.  The 
> firmware shows as 1.04C and IOC of 1.02.
>
> Rather than start troubleshooting each little issue I would like to 
> put together a plan to bring everything up to spec and then upgrade 
> from Rev A to B.  In the immediate future I want to add one more 
> module, namely the K160RX and of course will need the right upgrade 
> kit(s).
>
> I have had enough kit assembly experience in the past that I THINK I 
> can do the work, but I need help with a plan that puts all the steps 
> in the right sequence, given the early version I have and the possible 
> fixes that may be needed along the way.  I have the Revision B upgrade 
> documentation but I need some hand holding as to what pieces I will 
> need and in what order.  I really want to do this right and not mess 
> up this nice radio.  At some point I may just decide I need to go the 
> Builder-for-Hire route.  You get the idea!
>
> Any help would be appreciated.
>
> Thanks,
> Dan
>

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