[Elecraft] K3 synthesizer problem

[Tom Kramer]

I am a new person in this group and I will admit that I have not looked at many of the hundreds of previous posts so I will apologize in advance for being a bit lazy if this topic has been dealt with before.

I have a home assembled K3 SN 4210 that has developed a most annoying problem. I have exchanged a number of emails with Gary Surrency about this with basically no conclusion and an apparent lack of desire to solve it.

I discovered that when attempting to transmit between 24,910.0 and 24,930.0 the swr bar graph shows a pulsating full scale reading and the dial reads SWR between 9:1 and 12:1, and power output of maybe 20 watts. Outside this range SWR is normal and power output is full 100 watts. This can be into a resonant antenna or dummy load.
I have done the synthesizer calibration preceded of course by the ADC ref calibration multiple times. I sent Gary a list of all the parameters outputted by these tests and he says all look to be in the normal range. I have since discovered that the same problem appears between 28,500 and 29,000 Khz as well. I am trying to keep this somewhat short so I didn't supply every detail of the testing.
Have other people experienced this and what if any solution did you find? Gary suggests a new synthesizer board @ $200+ but no at this point there is no guarantee that will fix the problem.  I have made arrangements to test this with another K3 next week, but curious if this problem is something new.
Tom NQ7R
Casa Grande, AZ