[Elecraft] K2: No sidetone

[twimsatt at wimsatt.truepath.com]

I am not getting a sidetone on my K2.  I have run through the  
troubleshooting section for the sidetone and have reason to suspect  
something is up with U8, the D-A converter.  I have 5V on pin 1 of U8  
and the corresponding pin of Q5.  There is no AC signal from U8.
The sidetone was working in phase 1 of construction.  What else can I  
check to determine if it is the D-A converter?

Thanks!

Tom
KB3PNU