NEW ORLEANS (AP) -- Superdome officials warned just months before the Super Bowl that the venue's electrical system could suffer a power outage and rushed to replace some of the equipment ahead of the big game

While the cause of Sunday's 34-minute outage is still under investigation, records released Monday show that Superdome officials were worried in October about losing power during the NFL championship.

Tests on the electrical feeders that connect incoming power from utility lines to the stadium showed decay and "a chance of failure," state officials warned in a memo dated Oct. 15. The documents, obtained through a records request by The Associated Press, also show the utility that supplies the stadium expressed concern about the reliability of the service before the Super Bowl.

The memo said utility Entergy New Orleans and the Superdome's engineering staff "had concerns regarding the reliability of the Dome service from Entergy's connection point to the Dome."

The memo was prepared for the Louisiana Stadium & Exposition District, the state body responsible for the Superdome.

Authorities then authorized spending nearly $1 million on Superdome improvements, including more than $600,000 for upgrading the dome's electrical feeder cable system, work that was done in December.

"As discussed in previous board meetings, this enhancement is necessary to maintain both the Superdome and the New Orleans Arena as top tier facilities, and to ensure that we do not experience any electrical issues during the Super Bowl," said an LSED document dated Dec. 19.

Superdome commission records show a $513,250 contract to replace feeder cables was awarded to Allstar Electric, a company based in suburban New Orleans.

A lawyer for the LSED, Larry Roedel, said Monday a preliminary investigation found the replacement work done in December did not appear to have caused Sunday's outage.

Entergy and the company that manages the Superdome, SMG, said Sunday that an "abnormality" occurred where stadium equipment intersects with an Entergy electric feed, causing a breaker to create the outage. It remained unclear Monday exactly what the abnormality was or why it occurred.

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The lights-out championship game proved an embarrassment for New Orleans just when it was hoping to show the rest of the world how far it has come since Hurricane Katrina in 2005. But many fans were forgiving, and officials expressed confidence that the episode wouldn't hurt the city's hopes of hosting the championship again.

To New Orleans' relief, NFL Commissioner Roger Goodell said the city did a "terrific" job hosting its first pro football championship in the post-Katrina era.

"I fully expect that we will be back here for Super Bowls," he said, noting a backup power system was poised to kick in but wasn't needed once the lights came back.

Fans watching from home weren't deterred, either. An estimated 108.4 million television viewers saw the Baltimore Ravens beat the San Francisco 49ers 34-31, making it the third most-viewed program in television history. Both the 2010 and 2011 games hit the 111 million mark.

As for possible culprits, it couldn't be blamed on a case of too much demand for power.

Meters showed the 76,000-seat stadium was drawing no more electricity than it does during a typical New Orleans Saints game, according to Doug Thornton, the Superdome manager.

He also ruled out Beyonce's electrifying halftime performance. She brought along her own generator.

Officials with the utility and the Superdome were quick to note that an NFL game, the Sugar Bowl and another bowl game were played there in recent weeks with no apparent problems.

Determining the cause will probably take days, according to Dennis Dawsey, a vice president for distribution and transmission for Entergy. He said the makers of some of the switching gear have been brought in to help figure out what happened.

Cinthia Hedge-Morrell, chairwoman of the New Orleans City Council's Utility Committee, called an emergency committee meeting Friday with Entergy representatives and others, seeking additional information.

The blackout came after a nearly flawless week of activity for football fans in New Orleans leading up to the big game.

Mayor Mitch Landrieu told WWL-AM on Monday that the outage won't hurt the city's chances, and he joked that the game got better after the blackout: "People were leaving and the game was getting boring, so we had to do a little something to spice it up."

The city last hosted the Super Bowl in 2002, and officials were hoping this would serve as the ultimate showcase for the city's recovery since Hurricane Katrina in 2005. The storm tore holes in the roof of the Superdome and caused water damage to its electrical systems, and more than $330 million was spent repairing and upgrading the stadium.

Sunday's Super Bowl was New Orleans' 10th as host, and officials plan to make a bid for an 11th in 2018.

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Associated Press writers Beth Harpaz, Brett Martel and Barry Wilner contributed to this report.