backward capacitors
I have myself done first power up of circuit boards which I designed a number of times mostly in the middle 1980s. In my case the most troublesome initial bad outcomes involved severe local overheating. I dealt with this possibility by using initially very short connection of the power supplies. I may have started with about one second of time, then doubling. In between applications I would pass a hand over the board seeking to detect local overheating.
After one alarming experience I learned to assure that neither my hands nor anything else sensitive was over the board at the moment of first application of power. In that experience a tantalum capacitor which had reverse power applied to it actually expelled the central pellet at considerable velocity. It hit the wall and not me, but the experience left an impression on me.
While I do recommend short time, I don't think that slowly ramping up voltage is very clever. Lots of things don't like prolonged low voltage on their supplies.
While pellet expulsion is particular to certain types, there are quite a few capacitor types which do bad things if the voltage is reversed--which is a possible consequence of several types of error.
[fixed a typo, and adding note to bow to the subsequent post by MurphyWasRight, who clearly has done a lot more of this than have I, and gave several useful practical tips]
Last point--We all used to call first article turnon the "smoke test" for good reason.
Last edited by archae86; 23rd Mar 2018 at 18:31.
Reason: fixed typos, tipped hat to MWR, mentioned smoke