Sound like another 400SM ICE Power supply failure to me. Connections do not matter at this point if the dip switch on the Pamp8-100 is set; power mode is set to on. The fans should be running and the 1-8 Blue Led's for the channels should be on as well.
I am using the Rotator Mount with another version Samsung Qled variant and the rotation control was added in a update last year. Control done via Programming;
Version 209
Fixed DRIV-8134 (DRIV-8569): Serial control not functioning
Fixed Color buttons with Network control
Added Display Rotator Control device specific command
I have a spare, where are you located? Alternatively can order part number below;
https://www.mouser.ca/ProductDetail/Molex/39530-0004?qs=cJvWYcaovXzY3zXnMJaAzw%3D%3D
Press the power button and select restart then hold down the back button until it the "welcome to Halo" appears.
Should see the the Control4 Snap/AV logo flash on/off a few times before that happens though
Give this a shot from this thread, Only ever came across 1 unit that never took a re-flash. Saved at least a dozen for locals in my area thus far this year.
Used this method for half dozen years now.... I find the easiest for Inwall is to load the T3 firmware in the Rockchip software. Next, hold down reset button beside the microphone while connecting the USB cable to the T3 inwall. Should start flashing. Lastly, re-boot the touchscreen with Rockchip software turned off or closed for reflash to load.