I use them on my ef 104 they work fine.

Try sending your servos to H.H. services and have them replace the feedback pots for about $20 each. Your jitters will be gone for a season or two.

Scott

With normal wear on JR servos with ball bearings, there is a possibility that a slop develops in the servos and we usually replace the gear train with a new set of gears. In my case I noticed the top case where the bearing seats had gone loose thereby inducing a slop after the new gear train installation. Here is what I did, I took a thin plastic tape and placed it in the bearing housing wall. This perfectly centered the bearing and also ensured the bearing sits in the housing very snugly and therefore totally removes the slop .... a simple and sure fix of JR 8411 servo slop. happy landings