Korg Poly800/EX800 Users

Hello.

I'm new to the list, so maybe few words about myself for a start. I'm
23 from Warsaw, Poland. I'm studying Electronics here at the Military
University of Technology in Warsaw, and sound synthesis is my hobby.
I've been using Poly-800 for 6 years now, and some time ago I found
this switched filter slope mod that I wanted to apply to my unit. 

The problem is, that I've tried both using a standard switch and a
100k pot, and after each, there's no sound at the output. The filter
chip is ok, and C103 was soldered as instruction stated, because when
I desoldered switch/pot from 5&6 pin of the chip, everything went back
to normal. Maybe someone here had same problem and/or maybe know what
could possibly went wrong ?

X-Electric.