[JohnH]

Bill wrote back to me by return...very good service (as always) and pointed the finger at drivers. Well I thought I had eliminated that possibility as the 2k was working ok on the same setup but hey what the heck...so I tried the 4k with CCDOps on a win 7 machine and presto it was fine!

So not a camera fault then.

I realised my error must have been the win 10 upgrade I did a month or so ago on my astroimaging laptop. I had thought to save time by accepting M$ofts option to preserve all my apps and files - then I would just reinstall the things that broke. This was a bad plan. It worked but I did have to re-install CCDSoft and did get the odd error message before the session when the 4k stopped working completely. So I have ended up doing a clean Win10 install and fresh installs of CCDSoft, AstroArt etc. Everything is now functioning as it should (at least as far as a bench test goes). Just need a clear night now to see if it is stable in real conditions but I am hoping the issue was just an old driver conflict or compatibility issue.

Here is the lesson I should not have needed cause I have been there before - if you want to upgrade to Win10 - back up your old machine, do a format and fresh install of everything. Yes you will have more work to do but it is safer and you will end up with a faster and more stable machine at the end. The M$ update might work for a standard office type machine but with the odd bits of software and many non-standard usb devices we have on obs and imaging boxes I think it is likely to let you down.

BTW Win10 has some nasty defaults you may like to disable if you do not want patches and reboots in the middle of an imaging session, Cortona snooping on everything and unwanted adverts fired at you.