one of my customers is a large manual machine shop and he brought in last year a used lathe from japan machine company circa 1950's.The people who sold him the lathe hooked it up for him.
When he started the machine this morning smoke started comming out of the relay control cabinet. He immediately shut down the machine and turned off all power and upon opening the cabinet found the control transformer which converts 480 to 120 hot and smoking.
He called me and i went down to trouble shoot the machine and found that some electricain or other individual had tapped a 120 volt duplex receptacle off the low side of transformer and had not fused the receptacle and that also some of the original ceramic fuses one of which protected the transformer had been replaced by a modern fuse block as ceramic units are no longer available.
What i found out was a 120 volt work clamp light that was plugged into the outlet had grounded it self out and because wrong type of fuse was used trying to use an american cc NEMA equivelent insead of a J- IEC type the transformer overheated and would have caught the machine on fire had my customer loaded on a piece of work and let it run in auto pilot while he walked away to do another task.

this time i was able to catch a fire in progress and see what had been done wrong before all the evidence was destroyed.
I see many improper modifications made on machines all the time like this and correct them when i find them . But this whole used and rebuilt machinery market is kind of scary with getting a pig in a pock.
If any one would like further details or pictures for research purposes please let me know nickmarkowitz@hotmail.com