[Elecraft] [K2] Ooof.. Update

[Larry Kendall]

Don, thanks.

I understand about the band pass LC section and that is what perplexed me. 

Late last night I found and corrected a tiny solder short hidden under the connector on the KNB2 board. Of course it had to be pins 1 & 2 and you know what that would do.

Had to call it a night at that point per the whole work/job/employment thing for this morning and will reinstall into the K2 & test it tonight.

If this turns out to be the "only" problem I'll be a happy Ham.

Thanks & 73.

LK
-----Original Message-----
From: "Don Wilhelm" <w3fpr at embarqmail.com>
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Cc: "L Kendall" <k5end at att.net>
Sent: 3/21/2011 8:06 AM
Subject: Re: [Elecraft] [K2] Ooof..  Update

  That last R should have been R9, sorry for the typo (it is still 
morning - need more tea)

73,
Don W3FPR

On 3/21/2011 8:59 AM, Don Wilhelm wrote:
>    Larry,
>
> You are trying to analyze too much in the KNB2 without looking at the
> schematic.  The signal always passes through the Bandpass Filter.  It
> only goes to the amplifier to detect noise.
> So check the toroids L1 and L2, C3, C4, C6, C7, R8 and R8.
> The RX signal should pass through the KNB2 with only those components in
> place and working.
> Also check the soldering of P1 and its mating header on the K2 RF Board
> = make certain pin 1 has been soldered on both.
>
> 73,
> Don W3FPR
>
> On 3/21/2011 1:21 AM, L Kendall wrote:
>> I'm having a similar problem after installing the KNB2.
>>
>> So, I triple checked component location and applicable polarity and all
>> solder joints for bad joints or bridged/shorted solder pads; removed,
>> checked and re-installed the 2 bandpass toroid chokes, checked the ID
>> number on the caps.
>>
>> Checked the K2 RF board J12, and checked the mods to R88, R89&   R90.
>>
>> ...and the K2 is still nearly deaf as a post.
>>
>> Next, I jumpered 1&   6 on J12 and could then hear stations all over 40
>> meters.
>>
>> Checked WWV @ 10 MHz and I thought it was going to blow the speaker
>> before I could turn down the AF gain.
>>
>> So it looks like I did not screw up the K2 itself. That is a relief.
>>
>> I'm guessing the next thing to do is check U2 for correct voltage
>> output, and if that's OK see what I can measure on the RF amp. It's an
>> SMD and mounted on one of those SMD piggy back things for PCBs made for
>> the old school DIP ICs.
>>
>> Kinda frustrating, but it happens.
>>
>> Larry
>> K5END
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Tue, 2011-01-18 at 22:43 -0500, Don Wilhelm wrote:
>>
>>
>>> Try jumpering  (with a piece of bent wire) between pins 1 and 6 of the
>>> J12 header.  If receive comes back to life, you have a problem on the
>>> KNB2 board.
>>>
>>> Let us know the results.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>
>>> On 1/18/2011 10:26 PM, Brian Denley wrote:
>>>> I am beginning to think I may have wacked or damaged the PIN diode for the
>>>> T/R switch while adding the resistor for the KNB2.  That might explain no
>>>> receive or transmit  that I am getting now.  Does that make sense?
>>>> Brian
>>>> KB1VBF
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