My 5080 has just recently begun exhibiting an odd input problem. When powered on (cold-start) none of HDMI inputs (the only inputs I use) function correctly. Input pop-up windows show up normally in the upper-right corner, complete with appropriate resolutions, so I know it is receiving the signals, but I only see a black screen. This happens on HDMI inputs 4 through 7.
In diagnosing the issue, I was cycling through the inputs manually using the hardware button (cycles through all inputs), and eventually the HDMI inputs were displayed properly. Further testing showed that once inputs started working, all continued to work until the set was powered down. The issue and solution are (currently) repeatable, but I'm afraid that won't last long.
I'm hoping the community could provide some options and solutions. I've replaced laptop motherboards before, so I am comfortable working inside electronics, though nothing this big before. Brief internet searches showed me a number of the boards available for replacement, but I don't have a service manual, so I don't entirely know what I'm looking for. I am also not opposed to having it serviced by a pro- I live in Denver, Colorado USA.
Any suggestions would be welcome, and many thanks!