Incremental Encoder MMS

Yes as I read it, terminal D should be the ground

sorry i had overlooked that when drawing in the cable that the blue cable in the photo from the MESA (ground) is connected to pin D.

OK so is the 7I76E encoder jumpered for TTL mode?

I have now removed the resistors that I would not have needed at all, as I found out, the jumpers were already on TTL. Then I turned the rotary encoder again only in one direction (to the right). You can see that it counts from 0 to -1 and then +1 in the video. He then always repeats the whole thing.

Not sure what's wrong the A/B signals are not quadrature.
(they change at the same time, this is not possible in quadrature)

it looks like I have either the wrong or a defective encoder. I'll order another one. thanks anyway for the help