[Elecraft] K2: No audio after fitting KDSP2

[Mick Hall]

Hi.

My K2 has been working fine for a few months now and I was finding the background noise that gets pulled in very tiring, so I decided to buy the KDSP2 DSP filter.

The build went fine and so did the install. After turning on the K2 I checked that the menu settings were all there and followed the manual. I then realised I did not have the  speaker plugged in, so I plugged it in while powered up. I got a loud pop through the speaker, then silence.
 
I thought that perhaps I had missed a menu setting whereby I would have to enable the KDSP2 but couldn’t find anything so obvious.

I built the K2 with the Rework Eliminators installed, so I removed the KDSP2 and placed the header back in place and still I had no audio. I have also removed my KSB2 and KIO2 module so now I am back to the bare K2, but still I have no audio.

I can only assume that something failed when I plugged in the speaker whilst still powered on.

I have tried injecting a signal in with the Elecraft wideband noise generator and the cheap and dirty signal tracing document but with the headphones plugged in and the AF and RF gain at full, I hear nothing at all at any point, only a very faint hissing. Although the signal does register on the S meter.

I have also followed the troubleshooting in the manual and gone through the full alignment procedure as recommended but still no luck.

Could someone help with a place to begin to try and track down the faulty component or components.
.
Many thanks
Mick