My Preston worked flawlessly all day, no issues, then bizarrely the following happened (at approximately the 11th hour)
Instead of the usual slow rotation the motor makes to calibrate to the lens initially it kept wanting to make a fast rotation, flying along to the end stop and then jamming stopped against the end stop of the lens trying to push against the end stop instead of coming back to find the other end of the focus ring.
When dis-engaged the motor simply continued spinning in the same direction at the same speed.
No amount of re-setting, changing of power sources, checking connections, checking lenses etc seemed to rectify this.
What is even stranger, is that I have had it checked by Optical Support (UK Preston dealer) and they said they were unable to replicate the fault and that it worked perfectly.
I noticed that the motor felt unusually warm to the touch on the day, did I cause it to overheat?
Is there some in built protection circuitry that kicked in?
It's a completely random experience that has never occurred before, i've used the Preston 2 channel and single channel systems, the bartech and the HoFo and never seen anything like this.
Luckily it happened at the end of the day just as I was about to de-rig and they had an idea for a quick Steadicam shot as a cutaway for a final scene, I was unable to do this but we just went to sticks and handheld (as originally planned) and it worked out fine, but if this would have happened to me earlier it could have really messed up my day!
Has this ever happened to any of you before?
Any ideas what it could be so I can prevent this issue in the future?
The System is a Preston Single Channel Focus/Iris unit with DM2 motor.
Any input at all would be appreciated.
James "confused" Davis
Edited by James Davis, 21 December 2011 - 05:48 AM.