I have the same
windlass and it's new. Recently had same problem. The
electric motor in your case is making
noise so it's ok in dropping mode. I found, in my case, that sufficient weight needed to applied to anchor chain for the down function not to skip (the clanking sound you hear). Answer in that case is to lower enough chain by hand to apply adequate weight on windlass, then it works fine. Don't know if you can change settings on windlass to avoid this and it isn't all that convenient but that's what I do.
Pete