[Elecraft] K2 VCO Alignment only 0.02V @ R30

[Don Wilhelm]

Jeremy,

You are making progress.
That is a good indication that you have resolved the problem.
Yes, add back turn 16 of T5 and things should come into normal.

Hint - you may still have to spread/compress the T5 windings, but as an 
aide to know which is to be done, tune down from 4000 kHz to where the 
voltage at R30 drops below 8 volts.  Then adjust the turns on T5 to 
reduce the voltage, then re-check 4000 and repeat as necessary.

You will find the maximum voltage will be your 8.04 volts, and you will 
have to change T5 (or readjust L30) to reduce it.  You will not be able 
to see which way to go (compress or spread the T5 turns) with the R30 
voltage at 8 volts, reduce the frequency and then it will become 
apparent whether spreading the turns or compressing them will reduce the 
voltage.  In other words, 'sneak up an getting the 4000 MHz voltage to 
6.00 volts.

Once you have 4000 MHz voltage at 6.00 volts, check the low and high end 
of all other bands.  You may have to make compromises to get all of them 
in range - the 6.00 volts at 4000 kHz is not a hard and fast number, it 
is just a target that usually works.

73,
Don W3FPR

On 2/2/2013 8:52 PM, JeremyJones wrote:
> So I started tracing back and checking joints and reflowing solder.  I now
> have 0.760 @ pin8, 0.000 @ pin 13, and 0.00 @ pin 15.
>
> R30 is now showing 8.04V, but 40M is reading in the 13000khz range, with L30
> able to adjust frequency but not voltage.
>
> I'm thinking I may need to add back in the turn that was removed from T5
> earlier to bring everything into spec?
>
>