[Elecraft] K2 KSB2

[wsm at amaonline.com]

Hello
I just finished building the ksb2 ssb adapter for my k2 and am
having a problem with it. It will not key the k2 in ssb mode.
All the test and alignment went as they should, and the voltages
on all components are what they should be except for one. On U1 the
voltage on pin 21 is 1.2 volts instead of the called for 5.8.
Am using a new Icom HM-36 mic and it is wired as the manual says.
Does pin 21 of U1 having anything to do with the keying on ssb?
Any info will be appreciated.
Scott
N5SM