Doepfer

My A-133 Dual VC polarizer ws working fine all along and then suddenly the half's Manual 
knob has stopped effecting the signal. I've run all kinds of tests even with an oscilloscope 
and so I know something has gone wrong. The corresponding LED lights still change 
brightness evenly and accurately when you turn the knob but the signal is left unchanged. 
I know it's hooked up correctly, I haven't moved my doepfer since I got it and treat it with 
a lot of respect and care. I'm sure that there must be some defective part, it really seems 
like the only possible cause. 

I've never had a doepfer module turn sour on me and feel kind of sad, I don't even know 
what my options are to right the wrong. Can somebody give me some guidance about this 
particular module acting up this way? I'm in New York city, so I guess I'm pretty far from 
Germany.