PCR with degenerate primer

[qin ling]

Hi:

I am trying to fish out the cDNA of which 20aa N-terminal seq is known. I
have linkered cDNA as template. So in my PCR, one primer anneals to the
linker, the other one is a set of nested degenerate primers designed based
on aa seq. But I couldn't get any specific bands out of my PCR.
Anybody has done similar experiments with success?  Please give me some
briliant suggestions. 
-- 
qin ling