Thank you Henry!
Actually, I think I might have found the problem's source - that 3D version. Not something throwing TurboCAD as a whole out, but one drawing throwing its own layout by something embedded in it? Perhaps??? Drawings I'd made some time ago seem fine, though I had to try several before finding ones drawn in Model Space.
I'll explain in more detail what I had done....
The drawing is of a new version of that two-throw crankshaft I put on the gallery, closer to the real one I wish to make. 2D only, the long elevation and one end elevation. So far so good, at for a workshop drawing once properly dimensioned, then I did this to it:
Turned the main elevation into a Group, for copying into other drawings including the GA.
Tried to make a 3D version by Line Thickness (so unexpected, odd results for parts), slowly and painfully building it as a column of cylinders moved arithmetically to their respective "heights". So far the 4 webs were all circular. Then Selected the whole "volume" and rotated it about one axis from vertical to horizontal.
Still OK so far, I think. Returned to 2D view, modified one end web to the typica balanced shape, on the end elevation.
Is this is where it started to go haywire? Managed to make that end elev. into a Polyline - a struggle, the various lines and arcs just did not want to meet - then tried to turn it into an Extrusion. This on the same sheet as everything else - could that have thrown the co-ordinates out?
It was after this that nothing worked. I learnt long ago that if something goes wrong in TurboCAD gives no clue what or where!
So could the 3D version have implanted its own, rather random, co-ordinates; embedded so firmly they cannot be altered?
It seems my first, best action is to look at older drawimngs. Yes, they are still as they should be.
So, start a New drawing on a New file... I'll pause here and perform a quick test, the basics of the end elevation and central spine (a long rectangle) of the shaft, all neatly on the X-axis with the end elev. on (0,0).
Yes - new file, new name. Closed and re-opened, bears this out - all neatly where I wanted them, with the Grid and Rulers in line.
What I need to know, is what exactly I did wrong, to give some hope of not repeating the mistake, perhaps with a much more complicated drawing.