My only experience with this unit is having to pop three of them open at a festival in a jungle, to resolder the mains input pins directly to the header. From what I can gather that was simply due to a PCB design flaw, leading to the issue to appear at a certain age and ‘road life’.
Hopefully that has been fixed in a revision by now. But if you ever have one turn on, light up but not pass audio without any error message - time to get the iron out!
I’m fortunate enough to have inherited four broken Dolby-era Lake Contour Pro, from which I managed to put together two working units. The older one needs a fiddle to make the v5.8 controller software work in modern Windows, and it won’t do FIR, but you’ll be hard pushed to better the sound quality at the second hand price point if you ever come across a unit. There’s one for $749 on eBay right now I think.
https://www.prosoundweb.com/digital-developments-inside-the-design-of-the-lake-contour-processor/