[Elecraft] Sidetone level

[Yves Dussault]

 Hi K2 friends!
I have completed the building of my K2.
Everything just works fine, except the sidetone.
I hear a very weak sidetone. 
Adjusting ST P does change the frequency of the sidetone.

But:
 Adjusting ST L from 0 to 255 has no effect on the sidetone level.
The voltage at pin 1 of U8 remains constant at 5.0 V while I turn the tuning
knob to change the setting from 0 to 255. 

Could this be an indication that U8 (MAX534) is defective or what?



Suggestions, experts?

Yves Dussault-VE2ATD
Laval, Québec.