can be optical ( orange ) cable . They are fragile.
can be SBP unit also ...
You can try yourself. Just open, clean it and check if there are mechanical relays inside. Check them first. The big capacitors are next. The high power ceramic resistors next. And so on ...
yes, alkohol is ok if needed. Brush!
The very first alarm is relevant only. All the rest could be just a consequence. Take one by one.
You have big progress now - OSP operating system boots up.
The story of the fault helps very much. For instance, if the machine was moved, maybe a cable is damaged somewhere. It loks like there is a damage impacted more than one device. Power supply voltage surge?