Hi John, thanks for your suggestions /comments, you will be pleased to know I have eventually solved the problem though not without some hiccups along the way.? I checked the toolpath in 3D and it appeared OK, all the cutting paths were at the specified depth.? To my shame I couldn't at the time find the download link on this website so eventually found it on git_hub!!
Part way through my investigation the "ulp" complained it couldn't find java.exe (I presume javaw.exe had got lost too??), so latest java.exe was downloaded and sanity restored.? A plus was that for the first time the inbuilt previews worked, so I guess java.exe had been missing for years? -? very disturbing!!
Had to reset all the pcb-gcode settings as they now appeared as defaults with BOTH etch files now showing errors!!??? OMG what have I broken now ??? Finally resorted to trial and error adjustment of both Eagle design rules and pcbgcode setting and machine settings and many hours later I have eventually found values for all parameters that produce? apparently good gcode files.?? Happy to share these once proven by milling a board.
