K2 - PLL reference oscillator test

[W0CD]

Welp, made it to page 62 of the manual for the K2 build (receiver portion).
All resistances check out fine but the Frequency Counter test reads ~450kz
vs 12090khz expected. Additionally, I noticed the AGC calibration has
changed in the LED meter and it jumps a bit.

Any ideas?

Thanks



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[Don Wilhelm]

Order a replacement J310 FET from Elecraft and replace Q19 - that should
provide proper operation.

There was a time when Elecraft ordered a batch of J310s that turned out
to be marginal in the PLL Reference Oscillator.  Those have since been
replaced with NOS stock which work well.

In other words, order from Elecraft and not other sources.  The
thru-hole J310 has been discontinued by the manufacturer.  The part is
being produced only in the SMD version.

Evaluate the AGC calibration (and anything else) only after replacing
Q19.  The frequency of operation is not dependable without Q19 working
properly.

73,
Don W3FPR

On 8/30/2019 10:28 PM, W0CD wrote:
> Welp, made it to page 62 of the manual for the K2 build (receiver portion).
> All resistances check out fine but the Frequency Counter test reads ~450kz
> vs 12090khz expected. Additionally, I noticed the AGC calibration has
> changed in the LED meter and it jumps a bit.
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