I'm not sure if they sell memory, but I just had a resolver crap out on a Fadal 6030 x axis Glentech Servo Motor, which Mid Atlantic CNC had just replaced for me 4 months ago for $399.75, plus their fees for labor and travel.
I just ordered a new one from CNC Pros who sell Fadal parts on line for cheap. It was only $265. plus a core charge.
They may have memory also.
Fadal Parts Online