@sailor2005 Thanks for your questions, here are my answers:
All units were only powered via mains. First runs were always straight out of the box with no external clock and default configuration (of course, I crosschecked the settings for proper configuration).
I used several CDs, some from a new, pristine Deutsche Grammophon box set I just got, various standard ones from my collection, some extra high quality ones, all without scratches or other problems.
So I can first of all rule out the clock as the culprit. It‘s a Mutec Ref 10 Nano, which of course later on was used properly terminated, using 75 ohm Mogami cables. The Mutec also serves as a clock for my Gustard R30 DAC, my LAN switch and my SotM Roon bridge as well, btw.
Trying out the clock input, nothing changed as for the laser servo noises. TOC read times etc. were exactly the same as before on both units.
I also had tried the USB input with the first unit, which worked flawlessly via SOTM‘s Roon bridge and the I2S connection to my DAC, both with PCM and DSD.
I did a firmware update on the first unit with no changes as to it‘s laser servo behavior.
The second unit seemed to have already been configured for use with a 10MHz clock and 75 Ohm termination (first unit had a „straight internal / default“ configuration out of the box), so I also reset it to default. Still it had the more severe, constant servo noises I described in my above post. Because of that, I did not see any reason to perform a firmware upgrade, thinking a mechanical issue or a defocused laser might not be corrected by that.
I now am giving it a third try, but this time I ordered the PL200T from a different (of course official) dealer in the hope, that he might have a different batch in stock. Maybe I was just unlucky - I accept, that problems can happen and I had no problems whatsoever in returns/refund.
Let me make a final, but important remark. I never want to use a forum to talk bad about a brand or producer. I just want to seek help from people already having experiences with a certain gear. That’s also the reason, why I did some thorough testing, a firmware update and stick to the facts in describing the results of my tests in my post.
That’s also, why I’m glad, that you have asked specific questions to rule out possible errors via my side.
Of course, I contacted SMSL and am waiting for their answer - I am sure, they produce high class gear. Not having found any negative comments or apparent problems about their gear during my research for a solution speaks volumes about the quality of their products, imho.