I've learned from watching vintage computer repair videos on youtube that touching chips on a running system and looking for a hot one is a common troubleshooting technique.
Fun fact if you take a board out of a Burroughs B6700/B6800 that you think is bad (has a bad chip) if you drop it flat on the floor, chips side up from 36" (about belt height) 9 times out of 10 the lid on the bad chip will fly off. Turns out the heat from a failing chip heats enough to release the glue.