Any chance you got some 'moisture' into the panel ??
My first thought is , if EASY....remove panel, bring inside, sit on a floor register or next to a WARM heat gently blowing source overnight. Any moisture on a PCB can cause 'weird things' to happen. when I was making PCBs for security products, I'd toss into the dishwasher for 'short cycle- heated dry', then test on a bed of nails....
If it's not easy to remove, stick a hairdryer, on low heat under the panel for several hours. You may have to shroud the area to get the heat to the panel.
Since the panel does light up and gauges work, teh CPU is doing it's selftest and running, so 'most' of it is OK...