Tim.

On your Tx......
I had the same problem since my switchable 3ch was getting the most use.
I used the trace pen from RS that Racer mentioned.
I jst removed the screw the wipers were secured with, then applied the trace pen to fill the grooves(cuts) and wiped it with the edge of an index card.
Let it dry over night and reassembled. Works fine now.
I also used the RS teflon lube pen after it was back together to prevent "recutting" on the PCB/wipers.
Thought since it was teflon it may cause problems since teflon is non-conductive.........but no problems as of 2 months of use. No erratic or cutting out behavior.

Tony
ARS Software & Innovative Solutions
http://www.falcon1.net/~ars/rcmodels.html