[Elecraft] K2 12m Alignment

[Dauer, Edward]

I went through the same business with my first K2, apparently during the switch-over of trimmer suppliers.  None of the colors matched what they were supposed to be and the errata sheets didn’t help at all.  Don Wilhelm and Gary Surrency both went out of their way to help me sort it out.  

Although my DVM is theoretically able to measure capacitance, the long leads make it essentially useless.  So when I ordered my second K2, while I was waiting for it to arrive I put together a very inexpensive capacitance tester that sold for about $10.  It has PCB mounted test points that work with no leads at all, and the spacing is perfect for these little trimmers.  I then tested what I received in the second K2 kit before mounting them, found that there were still questions, and once again Elecraft came almost instantly to my aid.  But at least I didn’t have to undo anything, or puzzle about why something wasn’t working right.

Sounds as if the K2 trimmer supply is a recurring problem.  Using the capacitance tester before mounting them saved me a great deal of trouble.  Having bought it, I now test EVERY cap before installing.  Takes a while, but it’s reassuring.

There are lots of inexpensive testers available on the ‘Net.  I think this is the one I bought:  http://www.nkcelectronics.com/capacitance-meter-kit.html.

Ted, KN1CBR
    
    
    ------------------------------
    
    Message: 24
    Date: Sun, 26 Feb 2017 23:52:06 +0000 (UTC)
    From: Chuck Stover <k4qs1 at yahoo.com>
    To: "donwilh at embarqmail.com" <donwilh at embarqmail.com>, 	Robert Kasten
    	<bkasten at octavian.net>, 	"elecraft at mailman.qth.net"
    	<elecraft at mailman.qth.net>
    Subject: Re: [Elecraft] K2 12m alignment
    Message-ID: <1207157025.1459419.1488153126961 at mail.yahoo.com>
    Content-Type: text/plain; charset=UTF-8
    
    Bob, Don,
    I just finished up a K2 as well.? The trimmers I got didn't match the description in either the manual or errata, so I wasn't sure what I was looking at.
    I had to use clip leads from my cap meter and got too much stray stuff going on to accurately measure min and max.
    I talked to Gary in Watsonville.? Here's what we summized.? The larger bodied yellow trimmers went into c21 and c23.? The remaining 4 smaller bodied white with red band trimmers went into c32, c34, c44 and c46.
    It works.? I get good output on all bands.
    Don't know if this helps or not.
    Chuck K4QS
    
    
          From: Don Wilhelm <donwilh at embarqmail.com>
     To: Robert Kasten <bkasten at octavian.net>; elecraft at mailman.qth.net 
     Sent: Sunday, February 26, 2017 6:10 PM
     Subject: Re: [Elecraft] K2 12m alignment
       
    Bob,
    
    You have too much capacitance at C32 and C34.
    
    Contact Elecraft support and ask them to send 2 trimmer caps to replace 
    C44 and C46.? The ones you have with your kit do not have a small enough 
    minimum capacitance.? The p/n you need is E540011 and the bodies were 
    red the last time I saw them.
    
    The 35 to 70pF range you measured is higher than I would expect.? They 
    should measure about 20pF to 45pF.
    
    If you have a similar problem with the maximum power on 18 MHz as well, 
    ask for replacements for C32 and C34.? The part number is E540002 and 
    they have yellow bodies.
    
    See the latest Errata page - download it from the Elecraft website.
    Trimmer capacitors have become a problem for Elecraft over the past 6 
    months or so.? I believe you have brown body trimmers at C32, C34, C44 
    and C46.? Several of those were found not to meet the manufacturer's 
    specs for capacitance range and were dropped.
    
    73,
    Don W3FPR
    
    On 2/26/2017 5:41 PM, Robert Kasten wrote:
    > Finished my K2 in the last few days and really enjoyed the build. It was
    > just like old times.
    >
    > All bands except 12m have aligned OK...but I cannot get any more than .5W
    > output on 12m - no matter the C44/46 trimmer cap settings or the power
    > setting. And while it not fun, I pulled components C42,C43,C44,C45,C46,C47
    > and C48 and they all showed fine on the cap tester. C32 and C34 are
    > adjustable from about 35pf to 70pf.
    >
    ______________________________________________________________
    Elecraft mailing list
    Home: http://mailman.qth.net/mailman/listinfo/elecraft
    Help: http://mailman.qth.net/mmfaq.htm
    Post: mailto:Elecraft at mailman.qth.net
    
    This list hosted by: http://www.qsl.net
    Please help support this email list: http://www.qsl.net/donate.html
    Message delivered to k4qs1 at yahoo.com