Fear not!
This is a known issue and an easy fix.
I encountered this problem the moment I first powered up my used Monomachine. It was very worrisome, but I remembered reading a thread about it.
Info here: MNM freeze, but here’s the short of it:
HQ said that this can be caused by some oxidation on the cabling and that you can use oil-free dry cleaning spray to remove this from the cable connectors and sockets.
HQ: “If you are comfortable with disassembling the unit,… we recommend that you use a dry oil-free cleaning spray to remove oxide from the two connectors and sockets of the internal cabling.”
Further info, pics, and disassembly guidance at: Monomachine won’t boot