Diagnosing Exposure Problem - Shutter?

[smy128]

I recently shot a roll of film with a late 80s/early 90s Nikon D3HP I've had sitting in a closet for the last many years. On about half the images there is a white vertical band on the right side of the image and/or a dark blur on the far right side. This only occurs on some images, while others are perfectly sharp and exposure is fine. I have included two of the screwy images, and one normal image as examples. I suspect this is a shutter issue as the majority of the bad images, I believe, where shot at shutter speeds at or above 1/1,000s. Does that make sense? Does anyone have any other ideas of what the problem is? Is this fixable?

Thanks

 

[sevo]

Shutter capping - the first curtain is slow, or the second is fast.