Tonepad MXR Noise Gate 2

[markr04]

Hello. I built the MXR Noise Gate 2 (Callate Gate 2, Rev.1.Feb.20.2004) on the Tonepad site and it doesn't appear to be doing much of anything. I've checked all joints, etc. All is well.

1) My guitar plays through it like nothing is even there.
2) Sensitivity pot does nothing.
3) Attenuation pot only mutes the input when turned all the way. In fact, this is the only way I can get it to mute the noise of my other pedals. But when the noise goes away, my guitar won't come through either.
4) Attack and Release pots don't appear to do anything.
5) There is a 47pF cap shown on the board diagram, but it's not in the parts list or in the schematic. I put it in there anyway. Should it be a different value? Should I just remove it?
6) In a build report, I saw this: "Definitely add the 68pf cap to stop the "chattering" at the decay threshold". Anyone know what this person is talking about? Add it where... replace which one?

Thanks so much for your time!
Mark