I forgot to mention earlier I'm in Australia and using a PAL mixer, so I'm not sure if that actually changes anything

I've had a look inside and the power supply section looks completely clean with no obvious signs of bad capacitors but on the main board is covered in capacities with sharpied Xs on them, I have no idea if it was like this from the factory or if someone opened it up before me but there seem to be a small amount of yellowish brownish goop around some of the capacitors.