Both of my Ioptron mounts, a CEM70 and a CEM40, perform well.  However they both suffer from a build flaw wherein the counterweight bar is not accurately aligned with the DEC axis mount.  This results in a tendency for the RA axis to swing either clockwise or anticlockwise  when all is otherwise correctly  balanced.  It is possible- apparently - to fix this misalignment by moving the CW bar slightly within its housing by adjusting the top bolt and two side screws.  However - the bolt being very tight -  I found this difficult and neither did there seem to be sufficient play to make the adjustment.

A simple fix that does not incur the hazard of opening up the housing is to attach some 'side' weights  to the CW bar –to the left or right as needed to counteract the swing.  A simple way to do this is to remove the locking screw from one of the counterweights and replace it with a 30  cm M10 or M8 screw thread rod as appropriate.   Weights comprising nuts and washers are tightened into place near the end of the rod  and then the end attached onto the original locking screw and handle via a long bolt.  This - now lengthened and weighted bolt is then used to tighten the weight back onto the CW bar and simply rotated until the correct point of vertical balance is achieved.

Tim
Like