My second hand TinLizzie has terrible encoders on the carriage.

I want to purchase new ones (improved)

and was told another manufacturer uses the same style only better built. Any of you know what I am looking for?
Are the controls (on the handles) available thru another manufacturer? The right handle control is sticking.
Been getting requests to do some quilting projects and this thing is manual stitch only at this time.
Thank you in advance
Kim