One works, the other doesn’t. Both have bad capacitors. Curiously, the Aopen motherboard uses Nippon Chemi-Con capacitors at every location where one is needed…everywhere except those three locations, where no-name caps are used. The Samsung LCD panel was dead to the world and only hissed when plugged in. Switchmode power supplies tend to make noises at times, particularly when they’re having trouble staying in regulation. At that point, the switching frequency may drop into the range of our hearing. Turns out it was more bad caps. Some repair shops told the previous owner that it wasn’t worth fixing. I told them it was, and that I surely could. They told me to haul it away anyway.