I'm surprised that no one has mentioned that the SA 365C Dauphin had a single channel push pull (Richoux) cable to the tail rotor controls. The servo was a single system only therefore the cable was also the manual reversion in the event of hydraulic failure. The only problem I ever encountered with this during 4 years was where the cable covering had been allowed to deteriorate allowing water into the cable inner. Corossion caused stiff controls. Basically poor maintenance.
The design of this cable was in effect a solid steel flexible blade running in a series of small bearing.
Interesting that Aerospat returned to conventional rods with the 365N series. I suspect this was purely a commercial rather than a safety issue.