[cctalk] Decwriter III self test issue?

Hi all, I recently acquired a very nice decwriter III and it seems in good nick. However, the self test "hangs" on the return direction of the second line. Here is a video on it: https://youtu.be/pj6rk5Dlnbk Anyone have any ideas where to look? In local mode, it appears to work properly. I haven't tried any external serial connection yet. 73 Eugene W2HX My Youtube Channel: https://www.youtube.com/@w2hx/videos