MOTM

Hi all,

I just assembled a '420 and am getting a strange problem. I wonder if 
anyone has any thoughts on where the problem might lie:

In HP mode the filter works correctly - and sounds great - with no 
resonance, but if I turn up the resonance, I just fade in more 
unfiltered sound instead of increasing resonance. So that with the 
resonance all the way open, there is effectively no filtering going on.

When I put it in LP mode I hear nothing from the inputs at all.  If I 
turn the resonance up I get a regular clicking. If I open up the res 
the clicking slows down, and if I adjust the filter freq, I can hear 
the filter acting on the clicking, but nothing from either of the 3 
inputs is going through.

NF is a weird mish-mash of both the above.

After I first assembled it, it was doing this, then I double checked 
some of the joints and via holes and it started working fine, then I 
inserted a cable into the fm jacks and it went back to having the above 
problem. I've gone over all the stuff I did to get it working right the 
first time and no luck.

I'm inclined to think that, because I had it working fine at one point, 
the problem is minor and that I'll find it in time - for example 
something was jarred loose by inserting that cable - but I'm wondering 
if anyone has any suggestions on places to start?

Certainly nothing is loose to the touch, and everything seems to be in 
the right place, but obviously I'm missing something, or it would be 
working.

Any help much appreciated,
Matthew