I've searched online and also come across this post here ( viewtopic.php?t=6509 ) and can't seem to find any answers.
My MiSTer was working fine for around a year until it suddenly stopped loading cores. As soon as a core is selected the MiSTer will go black, the monitor will report no signal, and the only way to reboot it is to turn off the power supply.
I believe this issue is different from the RAM issue in the linked above post because mine has been working for over a year now and running the mem test detects the ram as well as reporting no errors.
I've tried fresh installs on the memory card with both regular update and update all scripts.
The usb ports all seem operational as it detects my bluetooth adapter for keyboard, wifi adapter for network, and joysticks/controllers. Any suggestions would be much appreciated. If I can't find anything, I'll just have to assume the board itself is somehow the problem...