[Elecraft] Filter TOO wide on my KX1

[Don Wilhelm]

Ken,

Soldering problems on R2, RP5 or D5 and D6 can cause that problem. At 
one end of rotation of R2 (the bandwidth pot) you should have near 6 
volts on the cathodes of D5 and D6, and at the other end of rotation you 
should have near zero volts.
You can measure with your DMM.  I suspect you have zero volts all the time.

73,
Don W3FPR

On 4/9/2015 2:43 PM, Kenneth Talbott wrote:
> Even in the extreme counterclockwise position of the Filter pot, the width
> is TOO wide.  A full quieting CW signal (not really strong, simply above the
> noise) can be heard at diminishing volume 800 Hz above and below the center
> frequency (1.6 kHz wide!).  This is an older KX1 which I purchased built.
> Any suggestions as to where I should start troubleshooting?  I have reviewed
> the assembly documentation and schematic.  At the top end of resistors at
> pins 2 and 3 of RP5 what voltage should I expect at the extreme ends of R2?
> Can this be measured with DMM or would I need an RF voltmeter? Thanks for
> any suggestions.
>
>