Hi Kevin,
I doubt anyone will recommend this, but....
My old Pantah used to slip it's clutch every 6 months or so due to the springs being too weak (alloy clutch to brittle for stronger springs).
What I did was take all the plates out and wipe them with 400 enery paper. Just enough to take the shine off them, then pop them back in & off I'd go for the next 6 months.
If your going to get a new set of plates, then it might be worth trying this on your old plates 1st.
Jim
...oh,oh,.. here come the responses...