[Elecraft] Low R30 voltage also - K2 #3378

[Thomas D.Simes]

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" <DolfinDon@msn.com> 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" <cesch@nwhealth.edu>
> To: <elecraft@mailman.qth.net>
> 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
> > _______________________________________________
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> >
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-- 
Tom
 
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   "Z-80 system stack overflow.  Shut 'er down Scotty, the system's
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Thomas D. Simes                                 simestd@netexpress.com 
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