[Elecraft] Low R30 voltage also - K2 #3378

Sun Apr 13 03:22:01 2003

First, I would like to thank everyone who responded with suggestions - what a great group of folks this list is!!  Second, I would like to contribute back to the list that I rewound T5 with 17 turns on the 1-2 windings as Don had mentioned and was able to easily obtain 6V @ R30 durning the VCO alignment and the rest of the stage II tests were within limits :-)

Onward and upward with #3378!

On Fri, 11 Apr 2003 07:58:17 -0800
"Thomas D.Simes" <[email protected]> wrote:

> 
> Unfortunately I seem to be in this boat as well.  Up to this point #3378 has checked out 100% with no rework, but in the VCO alignment I cannot get more than 3.6 - 3.8 volts @ R30.  
> 
> Input voltage measures 12.1 - 12.0V under load (battery)
> I have verified that C72 is marked "271"
> I have verified that L30 is marked "1005"
> T5 1-2 windings (red) pass through the core 16 times
> T5 3-4 windings (green) pass through the core 4 times
> T5 core verified as 1/2" yellow
> 
> The windings are evenly spaced and the 3-4 windings are exactly (by winding count) opposite the 1-2 leads on the core.  Looks just like figure 6-16 except smaller and 6-16 only shows 14 1-2 windings.
> 
> Given my respect for Don's postings on the list, I am inclined to follow his lead and rewind T5 with 17 turns on 1-2.  I am curious though as to why this might be necessary though since the rest of the kit has gone so smoothly.
> 
> Also, is there enough wire in the kit to cover rewinding this guy or should I order some extra now from Elecraft?
> 
> Thanks!
> 
> On Mon, 7 Apr 2003 14:41:02 -0500
> "Don Brown" <[email protected]> wrote:
> 
> > Hi
> > 
> > The signal at 4.000 mhz is the MPU clock but it is outside the ham bands so
> > is 14.36.
> > 
> > The last several K2's I have built had the low R30 voltage I rewound T5 with
> > 17 turns (one more turn) and the problem was corrected. Squeezing the turns
> > is also ok to get the voltage up.
> > 
> > Don Brown
> > KD5NDB
> > 
> > 
> > ----- Original Message -----
> > From: "Charles Esch" <[email protected]>
> > To: <[email protected]>
> > Sent: Monday, April 07, 2003 2:01 PM
> > Subject: [Elecraft] K2 signal at 14,361.4 khz
> > 
> > 
> > > Hi,
> > >
> > > I have an almost completed #3315 K2 and I just installed SB board.
> > >
> > > All has gone quite well in building except for a few problems.
> > >
> > > 1. I have a strong signal ocurring at 14.36140 mhz that is about S1-2.
> > > As I tune down in frequency a few hundered cycles, in any mode, the
> > > signal drops off abruptly.
> > >
> > > I also have a less strong signal at 4.000 mhz that does not have this
> > > abrupt drop in the signal.
> > >
> > > I don't know if this was present before I installed the sideband board
> > > as I am not sure if I have listened at these frequency before.
> > >
> > > 2. The only other problem I have had was with VCO alignment.
> > > I was not able to get the voltage at R30 up to the 6 volt point with the
> > > L30 inductor adjustment.
> > > I found that if I compress the windings on T5 I was able to get there.
> > > The only problem, if it is a problem, is that the windings cover about
> > > 65% of the core rather than the 85% required. Rechecked components
> > > related, but did not find any problems.
> > >
> > > Thanks for any suggestions you have.
> > >
> > > Chuck W0KZM
> > > _______________________________________________
> > > Elecraft mailing list: [email protected]
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> > > Postings must be plain text (no HTML or attachments).
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> > >
> > _______________________________________________
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> > Postings must be plain text (no HTML or attachments). 
> > See: http://mailman.qth.net/mailman/listinfo/elecraft
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> 
> 
> -- 
> Tom
>  
> ======================================================================
>    "Z-80 system stack overflow.  Shut 'er down Scotty, the system's
>          sucking mud" - Error message on TRS 80 Model-16B
> 
> Thomas D. Simes                                 [email protected] 
> ======================================================================
> _______________________________________________
> Elecraft mailing list: [email protected]
> You must be a list member to post to the list. 
> Postings must be plain text (no HTML or attachments). 
> See: http://mailman.qth.net/mailman/listinfo/elecraft
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-- 
Tom

======================================================================
   "Z-80 system stack overflow.  Shut 'er down Scotty, the system's
         sucking mud" - Error message on TRS 80 Model-16B

Thomas D. Simes                                 [email protected] 
======================================================================