I have sent my Celestron Advanced VX mount in for warranty repair (2 yr warranty, purchased July, 2014). It has never been a good star tracker for photography, star trails have shown up within a couple of seconds of exposure, but I thought it was my problem in not properly balancing or aligning. More than one service rep suggested the power supply and connector, which I checked as having consistent voltage >12 and a tight enough connector. But with this "no response 17", and then a "no response 16" showing up on the hand controller without the ability to move the mount in any direction, this may suggest what others have experienced, that this is a "6 wire" generation I mount, whereas the newer "Gen II" mounts have 8 wires going to the motor to carry the current properly, I think. I will hopefully update this after receiving the mount back. Celestron did send a free shipping UPS label which is a relief on avoiding that cost.
Update: rec'd it back today, October 29, so it was only gone for a couple of weeks. The electronics was changed from the plug-in 6 wire connection to an 8 wire connection (22awg? ethernet cord?). I will now have to test how well it tracks.
Update, 10-31 tracking test: a bit better on long tracking, but my camera, Olympus E-3 (2007), is not very sensitive and leaves a lot of junk in iso's greater than 100! There was a sawtooth pattern developing in one shot, which someone suggested is a declination alignment problem. My north alignment was off when I checked it later, so some settling of the mount takes place. Folks in a Celestron Advanced VX forum are having good results using a off-axis autoguider, so for another $500, I might do that, an Orion Mini Deluxe Pro. The camera will need an upgrade as well.