Hey PurpleParidox,
Welcome to the Forum!
Shudders without control? If you haven't plugged the servo in backwards, it sounds like it's stripped
The stock Calypso servos aren't high end -- getting stripped when you least expect it happen.
For a sanity check, try another channel on the RX but if that doesn't work, it's time for a new 9g servo. I've got a HXT900 that's happily run my elevator since the stock servo stropped a few years back.