A bad indicator LED, a simple ten cent part brought the Keck 1 telescope to a stop this last week.
How can that be? Usually an indicator is just that, an indicator. While an LED may indicate a problem it is rarely the cause of the problem.
I was getting ready to leave the summit when the radio started to speak words of concern, it sounded like something was not working, an instrument rotator?
Worse, the Keck 1 computer room hosted a veritable crowd, from the summit supervisor to all of the techs. Yeah, this was not good, why are they all looking at me? Oh, h%#*!