It turns out that most of these mounts do not meet their specifications. Mine certainly doesn't. Despite lots of attempts to engage the vendor to remedy the problem or ot give me a replacement that does meet the specification, they refused. My most recent polite question about the situation was met with no response at all. I'd stay away from any iOptron mount with encoders if you have a long focal length telescope.
You can't even take a 10 second image with this system and get round stars if you put more than 40 pounds of equipment on it. These should not be sold until the vendor fixes the problem. It's very heavy and not suitable for portable use as well. All in all a product to stay away from.