[Elecraft] K2 building problem

[Don Wilhelm]

Gary,

The frequency display changing rapidly is an indicator of one of 2 things.
1) The BFO oscillation is stopping, or
2) The BFO signal is too weak to be displayed properly by the counter.

I would suggest that you check the soldering at X3, X4, C173.C174. RP6, 
D37 and D38, Q24, D36, R98, R99.  Reflow the soldering with a hot iron 
(750 to 800 deg F) if necessary.

73,
Don W3FPR

Gary Auchard wrote:
> I've just finished the assembly of part 2 on the RF board and ran into 
> a BFO problem during the testing on page 65 of the manual.  All other 
> tests have been right on the money to this point.
>  
> When testing in the frequency counter mode the front display is 
> changing rapidly when using the frequency counter probe inserted in 
> TP2.  If I tap the Band- button the display locks in at 4.91253.  When 
> I tap the Band+ button the display goes back to changing rapidly.
>  
> I can measure a good solid reading at pin 6 of U11 telling me the BFO 
> is working and the frequency displayed is 4.91253.
>  
> I cannot get a reading for the BFO High Frequency.  I've checked L33 
> and it's fine with no short caused by R116 being on top of it and has 
> a good continuity across the windings.
>  
> X3 and X4 are the correct crystals for that location and came from the 
> package marked 4.91 MHZ.
>  
> Anyone have an idea what the problem might be?
>  
> Gary Auchard - WB0MNA
> K2 sn. 6506
>