[Elecraft] K2 SSB Problem

[iz1dug at libero.it]

Hi Don,

I have found three resistors with a wrong value (R7, R9 and R4). I installed the resistors with the correct values but the problem is always present.
The current increase step by step until it does catch up the value 4A and the radio gone on Hi current protection when I push PTT on the microphone.
It is possible that the Q1 transistor is the cause of this problem? 

Thanks for your help

'73, IZ1DUG Fabio 

---------- Initial Header -----------

>From      : "Don Wilhelm" w3fpr at earthlink.net
To          : "iz1dug at libero.it" iz1dug at libero.it
Cc          : 
Date      : Sat, 28 Jul 2007 15:19:50 -0400
Subject : Re: [Elecraft] K2 SSB Problem







> Have you removed C167 from the RF Board?
> If you have removed it, there may be a problem with the ALC circuits on 
> the KSB2 - check D1, D2 - look at the schematic and identify the 
> components associated with Q1 and be certain all have the correct valus 
> and are well soldered.
> 
> 73,
> Don W3FPR
> 
> iz1dug at libero.it wrote:
> > Hi Don thanks for answer.
> > 
> > I checked diodes D3, D4, D5 and are correctly installed.  I make some test after the check for supply you more informations.  I turn on the K2 on SSB, I push the PTT, speak into microphone and I have : power output OK, the s-meter follows the voice but the current increase and arrived at Hi Cur limit (also without speak into the microphone). Push the PTT is sufficient for have a current absorbed but the wattmeter don´t show any power out.
> > I hope that these additional information are sufficient to comprise the cause of this problem.
> > 
> > Thanks for your help
> > 
> > '73 de IZ1DUG Fabio
> > 
> > 
> > ---------- Initial Header -----------
> > 
> >>From      : "Don Wilhelm" w3fpr at earthlink.net
> > To          : "iz1dug at libero.it" iz1dug at libero.it
> > Cc          : "elecraft" elecraft at mailman.qth.net
> > Date      : Sat, 28 Jul 2007 08:17:10 -0400
> > Subject : Re: [Elecraft] K2 SSB Problem
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> >> Fabio,
> >>
> >> I cannot be specific, but the most probable area causing that trouble is 
> >>   the area of Q2 and Q3 (those direct the BFO signal either to the 
> >> balanced modulator in SSB mode or back to the RF board for CW) or the 
> >> balanced modulator U5.
> >>
> >> Check carefully to be certain diodes D5, D4 and D3 are inserted in the 
> >> proper direction and in the correct holes.
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> iz1dug at libero.it wrote:
> >>> Hi,
> >>>
> >>> I just finished installing the KSB2 module on my K2 QRP version (full optional).  I go to operate for the first time but when I push the PTT I get this problem:  the current absorbed increases (the voltage decrease) until it exceeds the value 4 A (set at this value after some test) and the K2 switch off.  The current and the voltage values reading on the K2 display and on the multimeter are the same. I have this problem on all band but only in SSB mode (K2 works correctly on CW mode with full power 10-13W). The problem is repeated every time when I push the PTT. 
> >>> I use the microphone Heil MH-2.   
> >>> Any suggestions? 
> >>>
> >>> Good weekend 
> >>>
> >>> Ciao,
> >>>
> >>> IZ1DUG, Fabio
> >>>
> >>> K2/QRP #1702 and K2/100 #5909
> > 
> > 
> > ------------------------------------------------------
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> > 
> > 
> > 
> 


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