1 bit of ASM advice needed...

[Andrew Schrock]

Ok, I promised myself I wouldn't go to sleep until i troubleshot and got
my last (out of 3) ASM-1 VCO to oscillate. 

I finally did it, but with 1 problem: it doesn't respond to negative input
voltages... thus tuning it is a bit hard since it's so unbearably high
pitched. It's not a physical problem with the tuning trimpot, I can see
that it just doesn't _respond_ to any voltages below 0. PW, FM, and CV in
all work fine, just with a terribly high-pitched tone. 

This sounds like an easy fix somehow, but I'm pretty tired... if somebody
could privately email me a hint it would be much appreciated. 

Update: My semi-modular handheld filterbank is 1/2 built: envelope
follower, LFO, and Attack/Decay envelope generator are all online, now
only the VCF needs some troubleshooting time... 

Andrew
(whose time seems to get sucked up by a strange force as soon as he picks
up the soldering iron...)