[Elecraft] Lost Sidetone and Spotting Tone

["D.R. Weiss KIØRP"]

I just completed and installed the KPA100 in my K2.  I did not yet do the 
Control board modifications for computer control.  Everything checks out OK 
except I have no sidetone or spotting tone, either with the KPA100 or with 
the basic K2.  (I had them in the basic K2 before starting this 
project.)  I tried changing the sidetone source, via the menu, back and 
forth between U6 pin 25 and U8 pin 4, without success.

The only changes I made to the basic K2, as part of building the KPA100, were--
*remove pin 4 of P4 on the K2 Control board (p. 21 of the KPA100 instructions)
*upgrade main processor firmware to ver. 2.03D (furnished with the KPA100)
*upgrade I/O firmware to ver. 1.07 (furnished with the KPA100)
*install Aux RF (P6) and Aux 12V (P3) connectors on the RF board (p. 42 of 
instructions)

My questions: Are the Control board modifications REQUIRED in order to have 
sidetone, or does anyone know of any other likely sources of this problem?

Thanks,
Dave Weiss KI0RP
K2 #2249