"Vibrate the machine to cause the failure"
?
I can just picture the CE and his able assistant...
"Get me the IBM Special Tool FBH-4 from the van, will you?"
...
"Right. Here goes, watch that meter now..."
BONG BONG BONG BONG CLATTER
"Yup, that's the fault showing!"
Related, maybe...
With the big machines of the 1970s, like the 3033 (and perhaps
earlier), a little calibrated hammer was supplied so the CE could
whack each card to make sure the things were seated properly.
--
Will