[Elecraft] Noise Blanker Malfunction

[Lee Buller]

Good Morning Everyone....
 
My KNB2 has quit working...or...might be working all to well.  On FD, the signals on my K2 disappeared and the RX died.  I took the rig home after FD (I did not get to make one Q with the K2) and started looking at it with the email help of W3FPR.  Well, come to find out last night when I removed and jumpered the KNB2, the RX was good to go...better than ever...hotter than a pistol...smokin...well you get the picture.  With the KNB2 in the signals are reduced significantly...I can hear some loud signals....but they are very weak and there is not S-Meter or AGC action at all.
 
I cleaned the header pins and tried it again.  The RX was deaf.  I pulled it again, and put inthe jumper and...she was jumping off the table....hot RX again.  With the KNB2 in there was not S-Meter action....and now I have a lot of action.  The KNB2 is recognized by the K2 as installed when it is in...so that part of the circuit is working.
 
Reading the manual...and...reading the archives...I found very little information on troubleshooting the innards of the KNB2.  I understand the circuit...did some continuity checks with the DMM...I do not have a scope...and found nothing really apparent.  I plan to go through the KNB2 tonight and touch up each solder joint to see if that is what is wrong.
 
Does anyone have any info on how to troubleshoot the KNB2?  Or, should I buy a new one for $39 and not worry about it.  I hate to do that...but....
 
Lee Buller
K0WA
 


Common sense is in short supply - get some and use it.
If you can't find any common sense, ask for help from 
somebody that has some common sense. - Lee Buller