I'm using an STXL6303 with self-guider filter wheel on a 16" Meade LX200 ACF, all controlled by MaximDL 5 Pro. Have worked for years in this configuration. We seem to have a new problem: after finding a guide star, calibrating the guider on it, starting guiding, and setting up a series of exposures on a target, the guider fails after a few minutes, with a pop-up error box: "Guider Error (17)", and the guiding stops. Sometimes we get an hour of guiding before that happens, sometimes just a minute. We switched to guiding with a piggyback telescope with an SBIG ST-i, using the same HDMI cable to connect to the remote guide head port on the cameras, and guiding works fine for hours. Switch back to the internal guider on the filter wheel, and we get "Guider Error (17)" again. This makes me suspect a hardware problem with the guider on the filter wheel. Thanks for any advice!