Staff Assigned: Bill Lynch stripes in ccd-images STL6303E

I have a question about the images from my SBIG STL6303E CCD-camera. I have this camera for many years and worked allways fine.

But now i have some issues.

As you can see on the image, i have black/grey lines in the image which are random in the images. Not all. Sometimes i can image without problems, but sometimes i get several images with this problem.
I made some tests. I made a lot of flats with the Mount/Telescope in the parkposiiton. This issue never appears.
When i do imaging, then i got these stripes in the images, sometimes only a few, sometimes about 60% of my images during the imaging-run for an object.

All is connected to 1 powersupply of 12VDC, Mount, focuser, CCD-camera and heating of the secondary mirror. The powersupply is over-estimated (12VDC/30AMP)
I replaced all my USB cables by new one of goof quality, but no improvement I use an ASA DDM85 mount and is connected by USB to the PC.

I’m not sure this is a camera issue, but something with the USB/PC or software ? or power supply ? Maybe it is better do use a dedicated power supply fot the CCD-camera ?

Any thoughts ?

thanking in advance,
Erik.