TAMPA — The bombs were bursting in air according to plan until about halfway through the annual Fourth of July fireworks display near Channelside Bay Plaza.

Then the "ooohs" and "ahhhs" gave way to frustration as a fireworks audience of several thousand people experienced long segments of silence between the explosions of color they'd come to see. Instead of a grand finale, the show seemed to peter out.

"There was no big finish," said Donna Zimmerman, 49, of Brandon. "Very disappointed this year."

A likely computer glitch forced a technician to abandon the pre-programmed script and run the show manually, accounting for the sporadic pace of the show, said Christopher Liberatore, vice-president of sales for Pyrotecnico, the company hired to do the show.

"At the end of the day, it's electronic, it's a computer," Liberatore said. "Everyone that has a computer that failed them and this is no different. Hardware and software do weird things."

Things were going fine until around seven minutes into the show, when there was a long pause in the action.

At that point, Liberatore said, the technician was trying to troubleshoot the problem. The script for the 15-minute show, choreographed to music, is in a computer file and the computer is attached by a cable to the firework-firing mechanisms.

When the script failed, the technician switched the cable to another computer loaded with the same file running simultaneously. The backup unit should have picked up the script without interruption.

But that didn't work, either.

So the technician used the computer to launch the fireworks manually instead. It's possible but very difficult to manually replicate a choreographed show, even for a seasoned technician like the one at the controls, Liberatore said. That means some of the fireworks never launched.

"He did everything we could have expected him to," Liberatore said.

That the backup computer didn't work leads Liberatore to suspect a problem in the computer file containing the script.

For spectators, it translated to a stilted show cut short by several minutes.

"It wasn't fluid. It didn't progress into a bigger display like most fireworks," said Marcus Rodriguez, 33, of Tampa, his two kids, Elijah, 7, and Jazmine, 5, by his side. They said they enjoyed the show nonetheless.

During those silent periods, people near Channelside Bay Plaza were seen leaving the area. But Zimmerman, the Brandon resident, stayed longer, not sure she had seen the end.

"Usually you know it's over because of the finale," she said.

A host of sponsors and partners help put on the annual Light Up Tampa Bay Independence Day Celebration, according to Channelside Bay Plaza, including Budweiser, The Florida Aquarium and Port Tampa Bay.

"It was unfortunate and disappointing," said Darrah Winkler, marketing and events manager with the plaza, "not only for those visiting Channelside Bay Plaza and the Channelside district but also for all of those involved in the event."

Winkler said more than 5,000 people showed up at Channelside Bay Plaza alone to see the show, not to mention those watching from vantagae points around it. She would not say how much Pyrotecnico charged for the show but added that the plza operators are "confident we will make things right."

That's the plan, Liberatore said. The national company, founded in 1889 and headquartered in New Castle, Penn., puts on more than 750 shows each year between July 1 and July 4 and has been running shows at Channelside for more than a decade.

The company will at minimum give the organizers credit for the show and might offer a free show next time, Liberatore said.

"These issues don't happen often but when they do we make it right," he said.

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Contact Josh Solomon at jsolomon@tampabay.com or (813) 909-4613. Follow @josh_solomon15.