I have a jtek shiftmate with Campy 10 speed Record brifters with Shimano DuraAce 9 speed derailleur and cassette. It was all working fine until recently. Now the chain skips when I am on the small chainring in front and try to shift to the smaller 2 or 3 cogs on the cassette. Turning the adjusting barrel on the derailleur seems to make no difference in the tightness of the cable or the shifting. Any ideas on what is the problem and how to fix it? Thanks.
Bill