Overheated
Lots of stories of this type but the one that always springs to mind is the waste disposal company with OKI Microline 132 col dot matrix printers thundering away outputting the invoices inside huge cabinets/acoustic hoods. Same as the story above, you needed breathing aparatus to go into the portacabin and I hated going there because I always ended up with mud on my suit trousers wading across the site.
Called out one day, "not printing anything". Printer was too hot to touch inside its cabinet because the fans on both sides of the cabinet had gummed up with the tar completely suffocating the poor Oki.
Not my problem I said, we only cover the printer, not the acoustic cabinet. You'll have to run it with the lid up until you get a new one.