[Elecraft] KNB2 - How can I tell if it is working?

[Sverre Holm - LA3ZA]

I built the noise blanker some months ago. I live in a relatively
noise-free environments, so I haven't had many opportunities to test it,
but on the few occasions when I needed it, I just could not tell any
difference. So I searched the archives for a simple test and came over
the simple 'rub a screwdriver across Q21' test from Elecraft's Gary
Surrency. Well, no action, so I started searching. I am a little
embarrassed to admit that there was a cold solder joint - with my 30
years of experience in soldering! 

Two seconds with a soldering iron, and now it works very well.


Sverre, LA3ZA
www.qsl.net/la3za

++++++++++++++++++
Date: Fri, 9 Nov 2001 18:18:58 EST
From: Unifiedtx at aol.com
Subject: [Elecraft] KNB2  Does it work or not?

when I completed the noise blanker board and installed it, I did not
think it 
was working. However, I couldn't find any random noise.  I asked Gary 
Surrency how I could tell if the blanker is working, and he told me to
turn 
the blanker on and gently rub a metal screwdriver across Q21.  If it is 
working you will hear a "singing" noise from this transistor.  Q21 is
the 
round metal transistor in the middle of the RF board.  I heard the
"singing" 
he described and was satisfied my blanker was working.  I have lately 
experienced a lot of random noise, and my blanker works great.  

Roy Morris 
W4WFB