Doepfer

hi guys,
got an A100 mini system the other week with the midi/cv convertor in 
it.
there seems to be a problem in that the cv and gate information is 
not being transferred to the internal buss as the VCOs or ADSR wont 
play unless hardwired with patch leads from the front panel. when 
this is done they all work fine for both gate and pitch.
ive checked the internal jumpers and these are in place but am at a 
loss with what to do next.
am i missing something obvious or does the midi/cv convertor not 
work in this way.
its driving me mad although thankfully i can work round it.
any suggestions would be much appreciated