I bought a Nikon Coolscan a few years ago to scan a large film collection I had taken over many years. It was very expensive. I was going to start after I retired. When I was ready, I started scanning. When it scanned it did very well. It died after less than 1000 slides and negatives. I contacted Nikon and they no longer supported it, nor were there any parts, nor any repair manuals. I contacted someone on ebay who cleaned them, he tried but could not find parts either. I gave up. It cost me about $3. per slide for those scans. I had a very expensive brick.
I think these manufacturers who don't sell replacement parts or manuals are just plain greedy. Sure things are complicated, but if they did sell parts and manuals, then if something goes wrong with a customer repair they shouldn't be held responsible. What they are doing now is just adding e-waste to landfills at a much faster rate.
I will no longer buy any Nikon product nor recommend any.