NEW ORLEANS (AP) — The cause of a 34-minute blackout at the Super Bowl remains under investigation, but public records released Monday show that Superdome officials were worried about a power outage several months before the big game.

An Oct. 15 memo released by the Louisiana Stadium & Exposition District, which oversees the Superdome, says tests on the dome's electrical feeders showed they had "some decay and a chance of failure."

Entergy New Orleans, the company that supplies the stadium with power, and the structure's engineering staff "had concerns regarding the reliability of the Dome service from Entergy's connection point to the Dome," the memo says. Those concerns were due in part to "circumstances that have previously occurred with the electrical service regarding transient spikes and loads."