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K2 s/n 7176 QRV

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R Thompson

K2 s/n 7176 QRV

Having just sorted out the KSB2 board, I made my first QSO with K2 s/n
7176. On a noisy 40M band I was able to check in the the afternoon
Aurora Net, and received a nice signal report from VA7XX with the power
set at 10W. Antenna is a Butternut HF6-V.

CW should be fun!

Ron VE8RT

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R Thompson

Re: K2 s/n 7176 QRV

Thanks! I had to wait for the KSB2 kit so I built the basic K2 first.
In my case I was thinking of keeping it as a battery portable, and using
an external antenna tuner if needed, but I'm of two minds on where to go
from here.

There were a couple of things that I had problems with, one of the more
annoying was the micro thin adhesive tape used to secure the green
filter to faceplate. The adhesive tended to stay stuck to the backing
tape and when it did come loose it tried to curl up on itself. If I did
it over again I might consider using a very small dab of some other
adhesive. Again the small black pads that get stuck to the rear top
corners of the front panel board, the adhesive tended to stay stuck to
the paper backing. Before installing these I'd recommend taking some
cotton tipped swabs and cleaning the area they're to be applied to with
isopropyl alcohol or "no-residue" contact cleaner first, or they might
not stick in place.

Its not in the manual, and others may have a comment on this, but I wish
that I had done it. On page 60, the installation of L33 using R116, if
I could easily do it over again I would take a few millimetres of
insulation off of the green wire to cover only the parts of the leads of
R116 that come in contact with the top of L33. I'm uncomfortable with
the bare leads of R116 pressing into the very thin insulation of the
windings on L33.

Some other things I did I won't promote here, especially after being
told not to do it :-)

The stack of insulators used on the PA amplifier transistors, when I
took the heatsink off to install the 160M option I took the stack and
used a bit of conformal coating on the loose insulators to stick them
together. The idea was to keep the three insulating pieces (per
transistor) together as a stack rather than having them fall apart when
the heat sink is removed to install another option, such as the
transverter kit which I'm considering doing later.

Also, I found that at the stage where the IF alignment is done, on page
67, that I got a more distinct peak when tuning L34 if the frequency
counter probe was not left plugged in, I don't remember if I'd left it
plugged in to TP1 or TP2 when I noticed this.

When it comes to mounting resistors on the backside of the board and it
isn't practical or possible to trim the leads after installation, I had
a simple solution. For most resistors the lead lengths will be
identical (there are a few that need longer leads and this won't work
there). In a place where a backside mounted resistor can be trimmed
later, install it with full lead length and trim them off after
soldering. Take the cut off lead as a cutting guide for those resistors
that need to be pre-cut before installation.

I'm pretty happy with how mine turned out, but I took a lot more time
than the average builder and almost all of the board work was done using
a headband style of magnifier. My normal reading glasses just weren't
up to the task. Another very practical tool I picked up recently was a
pair of high quality tweezers with cushion grip handles. When wearing
the magnifier these tweezers easily grip onto the extremely fine hair
that my long hair white cat sheds, and they're great for picking up or
placing parts too :-)

Lastly, another lesson learned, post any questions here if you have any
problems or doubts. The response time is quick and its much easier than
waiting for replacement parts in the mail :-)

Ron VE8RT

On Mon, 2011-08-01 at 21:48 -0700, David Dietrich wrote:

> COOL!! If this were Facebook, I'd "like" this status update. I have
> K2 s/n 7164 (10 W), that is under construction. All option boards are
> finished, and I am starting the control board tomorrow. The KAT2 L-C
> board was tough as the relays had to be installed first, and then the
> stuff on the other side.
>
>
> 73,
>
>
> David
> KC9EHQ
>
>
>
>
> ______________________________________________________________________
> From: R Thompson <[hidden email]>
> To: [hidden email]
> Sent: Monday, August 1, 2011 6:48 PM
> Subject: [Elecraft] K2 s/n 7176 QRV
>
> Having just sorted out the KSB2 board, I made my first QSO with K2 s/n
> 7176. On a noisy 40M band I was able to check in the the afternoon
> Aurora Net, and received a nice signal report from VA7XX with the
> power
> set at 10W. Antenna is a Butternut HF6-V.
>
> CW should be fun!
>
> Ron VE8RT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> 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
>
>
>

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Don Wilhelm-4

Re: K2 s/n 7176 QRV

Ron,

The last step in the left column of page 61 directs you to put tape on
the bottom cover at the L33 location so the resistor leads do not
contact the cover. If you did that, your suggestion for covering the
bare leads of R116 is not necessary. If you omitted that step, get out
your electrical tape.

On removing the heatsink - that can be done without losing the PA
mounting hardware if the K2 is placed on its side so gravity does not
pull the screws out. My favorite technique is to place a square of
electrical tape over the screwheads sticking to the top of the board and
T4. Then the screws do not fall out. Yes, you have to push the screws
back a bit to remove the heatsink, and if I am going to leave the
heatsink off for an extended time, I will put the nuts on the screws
finger-tight.
Conformal coating and other "solutions" can get messy if the PA
transistors ever have to be replaced.

73,
Don W3FPR

On 8/2/2011 6:57 AM, R Thompson wrote:

>
> Its not in the manual, and others may have a comment on this, but I wish
> that I had done it. On page 60, the installation of L33 using R116, if
> I could easily do it over again I would take a few millimetres of
> insulation off of the green wire to cover only the parts of the leads of
> R116 that come in contact with the top of L33. I'm uncomfortable with
> the bare leads of R116 pressing into the very thin insulation of the
> windings on L33.
>
> Some other things I did I won't promote here, especially after being
> told not to do it :-)
>
> The stack of insulators used on the PA amplifier transistors, when I
> took the heatsink off to install the 160M option I took the stack and
> used a bit of conformal coating on the loose insulators to stick them
> together. The idea was to keep the three insulating pieces (per
> transistor) together as a stack rather than having them fall apart when
> the heat sink is removed to install another option, such as the
> transverter kit which I'm considering doing later.
>

R Thompson

Re: K2 s/n 7176 QRV

On Tue, 2011-08-02 at 09:54 -0400, Don Wilhelm wrote:
> Ron,
>
> The last step in the left column of page 61 directs you to put tape on
> the bottom cover at the L33 location so the resistor leads do not
> contact the cover. If you did that, your suggestion for covering the
> bare leads of R116 is not necessary. If you omitted that step, get out
> your electrical tape.

That was done, although there was adequate clearance between the
lowest point of the assembly and the cover. What makes me uncomfortable
is having the bare resistor wire in contact with the fine enamel coated
coil wires. Its my experience with avionics that makes me very
sensitive to the possibility of vibration related damage.

>
> On removing the heatsink - that can be done without losing the PA
> mounting hardware if the K2 is placed on its side so gravity does not
> pull the screws out. My favorite technique is to place a square of
> electrical tape over the screwheads sticking to the top of the board and
> T4. Then the screws do not fall out. Yes, you have to push the screws
> back a bit to remove the heatsink, and if I am going to leave the
> heatsink off for an extended time, I will put the nuts on the screws
> finger-tight.
> Conformal coating and other "solutions" can get messy if the PA
> transistors ever have to be replaced.

The tape idea is a good one. The conformal coating was applied wet
to the insulator stack prior to hold it together, and allowed to get
tacky dry. No conformal was applied to the surfaces of the shoulder
washer that come in contact with the transistor, as you said it could be
a problem removing it from the transistor without damaging it. Its not
something I'd expect others to do as gluing things together could be a
headache at some point.
>
If I were to build another one for mobile, backpacking, or other
rough use, there are a few things that I'd do differently but wouldn't
recommend that others do.

Thanks Don, and others on this list for the help during assembly and
making it an enjoyable project overall.

Ron VE8RT

>
> On 8/2/2011 6:57 AM, R Thompson wrote:
> >
> > Its not in the manual, and others may have a comment on this, but I wish
> > that I had done it. On page 60, the installation of L33 using R116, if
> > I could easily do it over again I would take a few millimetres of
> > insulation off of the green wire to cover only the parts of the leads of
> > R116 that come in contact with the top of L33. I'm uncomfortable with
> > the bare leads of R116 pressing into the very thin insulation of the
> > windings on L33.
> >
> > Some other things I did I won't promote here, especially after being
> > told not to do it :-)
> >
> > The stack of insulators used on the PA amplifier transistors, when I
> > took the heatsink off to install the 160M option I took the stack and
> > used a bit of conformal coating on the loose insulators to stick them
> > together. The idea was to keep the three insulating pieces (per
> > transistor) together as a stack rather than having them fall apart when
> > the heat sink is removed to install another option, such as the
> > transverter kit which I'm considering doing later.
> >

Don Wilhelm-4

Re: K2 s/n 7176 QRV

Ron,

If you are going to use your K2 mobile in a vehicle that will subject it
to excessive vibration, then you concern about R116 and the L33 toroid
leads is valid. In normal circumstances (even in passenger car mobile),
it is not a problem. Ham radio does not normally build to avionics
requirements where safety while up in the air (and during takeoff and
landing) is the greatest concern.

73,
Don W3FPR

On 8/2/2011 7:03 PM, R Thompson wrote:

> On Tue, 2011-08-02 at 09:54 -0400, Don Wilhelm wrote:
>> Ron,
>>
>> The last step in the left column of page 61 directs you to put tape on
>> the bottom cover at the L33 location so the resistor leads do not
>> contact the cover. If you did that, your suggestion for covering the
>> bare leads of R116 is not necessary. If you omitted that step, get out
>> your electrical tape.
> That was done, although there was adequate clearance between the
> lowest point of the assembly and the cover. What makes me uncomfortable
> is having the bare resistor wire in contact with the fine enamel coated
> coil wires. Its my experience with avionics that makes me very
> sensitive to the possibility of vibration related damage.
>> On removing the heatsink - that can be done without losing the PA
>> mounting hardware if the K2 is placed on its side so gravity does not
>> pull the screws out. My favorite technique is to place a square of
>> electrical tape over the screwheads sticking to the top of the board and
>> T4. Then the screws do not fall out. Yes, you have to push the screws
>> back a bit to remove the heatsink, and if I am going to leave the
>> heatsink off for an extended time, I will put the nuts on the screws
>> finger-tight.
>> Conformal coating and other "solutions" can get messy if the PA
>> transistors ever have to be replaced.
> The tape idea is a good one. The conformal coating was applied wet
> to the insulator stack prior to hold it together, and allowed to get
> tacky dry. No conformal was applied to the surfaces of the shoulder
> washer that come in contact with the transistor, as you said it could be
> a problem removing it from the transistor without damaging it. Its not
> something I'd expect others to do as gluing things together could be a
> headache at some point.
> If I were to build another one for mobile, backpacking, or other
> rough use, there are a few things that I'd do differently but wouldn't
> recommend that others do.
>
> Thanks Don, and others on this list for the help during assembly and
> making it an enjoyable project overall.
>
> Ron VE8RT
>> On 8/2/2011 6:57 AM, R Thompson wrote:
>>> Its not in the manual, and others may have a comment on this, but I wish
>>> that I had done it. On page 60, the installation of L33 using R116, if
>>> I could easily do it over again I would take a few millimetres of
>>> insulation off of the green wire to cover only the parts of the leads of
>>> R116 that come in contact with the top of L33. I'm uncomfortable with
>>> the bare leads of R116 pressing into the very thin insulation of the
>>> windings on L33.
>>>
>>> Some other things I did I won't promote here, especially after being
>>> told not to do it :-)
>>>
>>> The stack of insulators used on the PA amplifier transistors, when I
>>> took the heatsink off to install the 160M option I took the stack and
>>> used a bit of conformal coating on the loose insulators to stick them
>>> together. The idea was to keep the three insulating pieces (per
>>> transistor) together as a stack rather than having them fall apart when
>>> the heat sink is removed to install another option, such as the
>>> transverter kit which I'm considering doing later.
>>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> 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
>