Re: Exos-2 PMC-8 - pier extension & axes stabilty



I have an EXOS-2/PMC-8, too.  If the clutches are locked, the wobble you are feeling will be the play between the worm and ring gears on each axis.  The two sets of teeth have either moved apart in use (the worm gear clearance is adjustable), or they left the factory like that.

My own mount arrived with very little play on either axis, but after some use, the RA loosened up. If you contact ES customer service, they can send you instructions on making the adjustment.  This problem recurred on mine after adjustment, and it is currently in Springdale (at ES's request!), undergoing what I fervently hope is a rejuvenation.  YMMV.

There is always going to be some imperfection in the way the ring and the worm interact on this design of mount, so some play will come with the territory.  If it's more than you're comfortable with, you can either adjust it yourself (ES can provide instructions, and Google is your friend), or you can ask ES if they'll do that for you. 

I think the key thing is whether the amout of play you're experiencing is stable, or increasing.  If it's stable and the mount is otherwise performing for you, perhaps you're ok.  If it's increasing/recurring (like mine was), you should probably reach out to ES CS and get some help.

The other thing is that, because of that pretty-much-inevitable mesh imperfection, people  developed the technique of balancing their scope 'east-heavy'.  Basically forcing the motors to drive 'uphill' all the time, so that the flanks of the gear teeth always mesh the same way, reducing backlash/play.  You will probably want to look into that as well. Lots of threads on that over on Cloudy Nights.

Hope this helps! 

- Bob

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