Need double exposures to show updated image in AA5

[Merlin66]

I'm using an ATiK16ICs under AA5....
Recently, when taking an exposure, the screen image doesn't update...the exposure according to the status bar looks OK but no new image...
I have to take a second exposure to update the image on the screen.
Why is this so?
Any input/ comment appreciated.

[Merlin66]

I've doubled checked the power supply, connectors etc etc but still get the problem.
What am I mising??