Celestron Motor Focuser flip??

[rubecula]

Got out last night after nearly a fortnight's cloud cover.  Set off to image the Wizard Nebula. I'll shorten what  could be a long tale.  The scope was out of focus - completely, nothing at all visible in either the imaging or guide cameras. After a lot of fiddling I re-calibrated the motor focuser after which it went to a random setting.  I did a GoTo 21400 which was where the scope had previously been in focus - still out of focus. So I set it to go to 0.  I expected it to count down from 21400 to 0 but instead it went upwards to 60,000 at which point the counter in SGP said 0.  I don't know why but I thought  if it thinks 60,000 is zero then instead of trying to go from 0 to 21400 I would try 60,000 to 38600 (60,000 - 21400) and lo and behold the scope was in focus.

I've no idea what caused all this.  Why it wasn't in focus as I had left it and why the focus setting was 38600 and not 21400.

Anyone any ideas?  Is this likely to happen again?

Thanks

[Davey-T]

No idea but I had a similar problem last night and I have two of everything, focusers went haywire, whoever one I connected to the same one moved, one had changed to a random Com port, had to reset them and recalibrate them then couldn't get two cameras to connect at the same time, lucky I started early so just got it all running in time to catch the California Nebula.

Permanent  setup and it all  worked fine a few nights ago, all I'd done was switch it off and on 

Dave