Trackspot "drifts" between bootups

Well, this is my first post in this Forum, so I hope I am posting in the correct area. Please forgive me if I am not.

I have been having this particular problem with our really old trackspots for about a year now, and I don't even know where to begin to fix it. I was hoping someone could help!

Here is the situation. First, I'll turn on the trackspots (by turning on our lightboard) and I will program our two trackspots to hit certain locations. When I turn off the light board (and thus the trackspots) and turn them all back on the next day, one of the trackspots has "drifted" downstage in location for every programmed cue. The other trackspot is right on. I can then reprogram all my cues with the new "drifted" trackspot, but if I do the boot up cycle again, the trackspot has now "drifted" back upstage! It's also kind of random to as when this drifting happens. It certainly does not happen on every boot up cycle.

Anybody have any ideas why this is happening? And if so, how I can fix it? Thanks in advance for any help you can send my way!

Trevor
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