Thanks for asking...
After checking all system components incl cables, power conditioners, etc., I determined that the preamp WAS the source of the problem. While the custom passive LDR has worked flawlessly for 7 years and, happily continues to do so, the designer determined that while the coding for the various was correct, activating selector switches in a specific order would trigger the pre to output no signal tho' the display did not indicate this. Coding will be modified to preclude this behavior.
Fortunately no issues were found with electronic components of the pre itself.
That's great news! Glad you were able to track which component was giving trouble, and attend to it promptly.
In fact I was thinking about this and discussing the very topic with another CLX owner. When you consider the materials, and build quality of the new Masterpiece series, the ML team have really put their thoughts together, arriving at a highly stable design on the stat panel, plus high quality parts. Taking into consideration cost of design & build, they have come up with each product within a certain range, and performance quality. There are some other speaker manufacturers who adopt this "cost no object" philosophy... but they still have issues! The owner's spend over 100grand on speakers and some don't work quite right. Of course after the tech team fly in and sort it out it does but that initial spend of 100grand plus will always be in doubt...
There's always room for improvement, in design, materials and the latest tech but there will always be limits to how the final product will end up.
Looking at the CLX's for example, there are areas where they could improve upon, obviously cost increases...
However, what the ML team have done with the CLX design is remarkable! Once again the high quality parts and especially the X-stat design elements, they've embraced all the things about earlier stat design, it's an absolute work of Art! The great thing is that ML still supports this very design and all of its parts even though the CLX's are no longer in production. If they ever renew the project and come up with a brand new concept/clx model, it will definitely not be any where close to what the price range was, especially taking into consideration the Neolith's. So when looking at it from a model fits which budget point of view; the Masterpiece series is really well thought out but then suddenly there's a massive gap from the Ren15A's to the Neolith's... and there's nothing in-between. This is where most probably a new ESL could be offered.
Since at the moment there's nothing within that gap, I would simply sit back and enjoy those very fine tunes!