[Elecraft] KNB2 Noise Blanker Not Working

[lfcluff at comcast.net]

I've had my K2 built for about 2 months now.  Everything works except the noise blanker.  I've looked at a lot of archives on this.  What I have done to test it is:

1.  Scratch the top of Q21 on the RF board to generate noise.
2.  Using an oscilloscope, I can trace the noise pulse through Q2-Q4 on KNB2 borad.
3.  I do see a  noise pulses on the "GATE" node and at the base of Q5.  When I turn off the NB, this pulse goes away as expected.
4.  I do not see any pulse on collector of  Q5.  Since the pulse on the base of Q5 saturates Q5, should I see anything on the collector?

I'm not sure if I have a bad Q5.  I am going to replace it today.

Thanks,
Leon, NE0N