Roger

I agree with your prognosis - but I stress it's only theory!

My mount is on order - so my advice at present is generic! My present set-up is various 'scopes and 'scope-pairs on a home-designed plate, in turn on a Vixen Atlux. If everything within your OTA is normal, this might be where the OTA attaches to the plate - or even plate-to-mount.

This could be almost anything! If the scope dinged the dome, it could have just jarred something slightly loose in the set-up. Recheck all bolts, tube rings, etc. for tightness. With the mount switched on (and in control) I'd gently get a hold of the tube and try moving it/restraining it slightly in all directions to see if there was any play, and if there is to identify that and eliminate it.

actually attach it to the OTA close to the camera so as not to place unnecessary moment loading on the focusser

pragmatic suggestion: Get a weight and attach it to the lighter camera....

Excellent. The knowledge base on these mounts is building up in here thanks to great team spirit.

I cannot believe that this weight swap has made any difference to the underlying problem. Generally less flexure and fewer low frequency problems will be experienced if the heavier weight is nearer to the fulcrum (as you had it before the swap). The underlying problem sounds more like the one Lukas describes in "losing USB..." , eventually resulting in a return-to-base repair, with which he is now very pleased. I hope I am not the prophet of doom, but I fully expect this problem to return to haunt you. Post hoc ergo propter hoc.

Lovely.

Luke I sent you a PM.

And I am more than a mite relieved too (will soon be a proud owner...)

Thanks for that. Our understanding of balance is identical - and the fact that the countershaft does not rotate throws another idea out of the window!

Note: Edited post above to eliminate ambiguity of axis descriptions, not changing any detail or context. Roger.

I see in a lot of places on here the phrase "balancing in different positions". Surely a telescope system is either in balance or out of balance? I am assuming by this phrase what is actually meant is to make sure that not only the counterweight correctly balances everything else, but that, when uncoupled, the plate, scopes, camera etc. has no left/right load at any position, i.e., not only is the OTA assembly balanced along the optical axis, but also perpendicular to it. Is this correct or is there some eccentric arrangement with this mount I have failed to grasp? I am sure I hasten to add that this will come clear when I get the mount. Assuming my assumption is correct, one possibly very useful addition to the software may well be something that, by slewing the scope around on its counterweight shaft axis with known Alt, with its counterweights at the lowest point and manually entered datum for OTA pointing to the horizon or pole star, coefficients of which direction the balancing error is might come in handy so that one can first get the OTA balanced correctly perpendicular to the optical axis, and then along it (this I believe would be quite straightforward software to write and very useful for those with complex OTA arrangements). A quick question for mount owners or ASA: When the mount is slewing, does the counterweight shaft rotate with rotation of the OTA on that axis? And a supplementary: If it does rotate when slewing, does it also rotate when the mount is unpowered and the OTA manually rotated about its countershaft axis? If affirmative to both, there may well be a very much easier way to do this balancing. I will talk to ASA offline - it may well be patentable.

As a systems engineer, a wheeled base will almost certainly mean you need to back I (of PID) way down. I stress I do not (yet) have one of these mounts, but that is what I'd first try.

If the troubles originally started following a lightning zap there could be latent damage on any pcb sadly.