[Elecraft] [K2] Erratic power control with base cw K2

[Alastair Couper]

That was it. The previous owner had put in the wrong cap in the cw  
bandwidth mod (.047uf instead of .01uf) and that made all the difference.  
Key waveform now good, and power control is stable.

Thanks for the great support effort. It makes all the difference, knowing  
that there is no problem so arcane and buried that it can't be fixed,  
unlike the newer rigs. I certainly learned a bit more about the K2, which  
was the point of all this.

Al NH7O

> Further testing here. I tried  changing the control board MCU to the
> previous firmware version, and no change, so that is ruled out. But...
> I do notice that my keying wave form is not right. The rise time is very
> slow, about 50ms, the falling time is about right. And the keying sounds
> like it, very mushy. So there is something in that circuit, with the
> keying bandwidth mod installed, that has changed.  Probing further...