[cctalk] unpleasant odor from VT100

i have a VT100 that is working fine (powers on, navigates setup, saves/restores settings, etc) but has an unpleasant burning/ozone odor coming from the rear of it. i suspect something is running hot but i am not sure what, i do not currently have an IR camera in my hands- working on that. the original power supply has failed and is currently in storage, so the terminal is being powered by an ATX power supply and adapter board for the time being. this eliminates the usual R27 as being the culprit. as best i can tell, the smell is strongest just above the power distribution board, around the neck of the CRT. appreciate any suggestions you might have!