Doc Brown’s flux capacitor in Back to the Future was a brilliantly functioning piece of equipment. Unfortunately for Collinsville, the capacitors in two emergency sirens could not make the same claim.

Collinsville residents were left confused for the second time in less than a month when an emergency siren blared Saturday, a day filled with sunshine. A bad capacitor was to blame in the sirens that malfunctioned Saturday and Aug. 23, Fire Chief Mark Emert said.

The faulty capacitors in both sirens were discovered and fixed Tuesday. Inspections are in process on the other nine sirens that have a similar circuit board. It is not clear what caused the equipment to fail, Emert said.

Collinsville has 18 emergency sirens.

“Even if both of the sirens were to fail, which they didn’t, in an emergency we have enough sirens scattered throughout town that no one would be out of earshot of a siren regardless of the situation,” Emert said.