JACKSONVILLE, Fla. – It can bring you back from the dead if your heart suddenly stops beating, but an automatic external defibrillator (AED) only works if you can find the device in time.
According to paramedics, six minutes is about all the time you have to revive a person if their heart stops beating before they begin to go brain dead.
The computer-generated voice of an AED at the Jacksonville Beach Lifeguard stand says: "Stay calm, check responsiveness, call for help."
WATCH: What is an AED?
It's a familiar voice that rescue swimmer Gordon Vandusen has grown accustomed to over the years. It's the assurance that the AED is working properly.
Every morning, he checks to make sure the batteries are charged and the pads haven't expired. But he never thought he'd actually have to use it.
"On all of our emergency trucks here, we carry boxes that have an AED, right here," said Vandusen, who put the AED to use for the first time in his career along Jacksonville Beach.
"My heart stopped, my heart stopped there, and luckily I was on the beach", said J.R. Bourne, who is thankful to be alive today.
Bourne said he was playing soccer on the beach with a friend when he started feeling lightheaded.
"Suddenly everything went black and my heart stopped beating. Someone on the beach called for help and a team of lifeguards just happened to be passing by," Bourne said.
Vandusen remembers hearing the screams for help and reaching for his AED.
"The AED told us, a shock was advised, so we gave him one shock, and after that the patient sat up, gargled some words and laid back down. He lost his pulse, laid back down, AED said 'shock one more time.' We shocked him again, and then this time, he was able to sit up and breathe on his own," Vandusen said.
"If I didn't have an AED, I wouldn't be here, point blank, I wouldn't be here, CPR wouldn't have been enough," Bourne said.
WATCH: JFRD explains how to use an AED
So how easy it is to find an AED? The News4Jax I-TEAM discovered that public places like the Landing, the Salvation Army downtown, and several senior living communities don't have AEDs on property at all.
Out of the 30 places the I-TEAM randomly checked, approximately 25 percent of the time, the staff either didn't know what an AED is, or couldn't find the actual device without asking a lot of questions.
Jacksonville Fire and Rescue Department Captain Stephen Grant said it helps to have signage at the entrance of your building notifying people where an AED is located.
"Whether the signs are at the elevators, near the exits to the building, the more visible they are, the more people will remember where they are at," Grant said.
WATCH: Tarik Minor interviews JFRD fireman about AED use
Grant told the I-TEAM there are more 700 AEDs in the city of Jacksonville, in city buildings and in police patrol vehicles. There are 225 AEDs in private businesses. But when every seconds counts, the I-TEAM went searching for them.
At the St. Johns Town Center and at the Avenues Mall, the I-TEAM couldn't find an AED anywhere on property. A spokesperson for the owner of both properties said there are three AEDs at each location. At both properties, two are locked up in offices and the third device is on a security guard golf cart.
The I-TEAM found that at the Jacksonville Ice Rink, the AED is also in the security office. Same goes for the AED at the JEA building.
The I-TEAM didn't see any signs directing the public to an AED at Jacksonville's public library downtown, but located the AEDs by the restrooms on each floor of the building.
At office buildings, like Prudential off San Marco Blvd, again, the AED was locked up in a back office, according to security guards we spoke with. Captain Grant said in an emergency, every second counts.
"For every minute that goes by you lose a 10 percent chance of survival," Grant said.
The I-TEAM did find buildings readily prepared for a heart emergency, including the Museum of Science and History, or MOSH -- where within 2 minutes of asking where to find the AED, four staff members came running ready with one in hand to help.
At the Brooks YMCA on the Southside, the AEDs are easy to find. They are located near the pool and workout areas.
WATCH: Fireman explains what an AED shocks
AED advocates said just like people are trained to reach for a fire extinguisher in case of fire, the public should be trained to reach for an AED in case someone's heart stops.
"Most people don't know that AEDs are practically dummy proof," Grant said. "Once you turn it on, it walks you through the steps needed to save someone's life, and it will only administer a shock after analyzing the victims heartbeat."
Paramedics said AEDs aren't used as much as they should during an emergency, partly because some are wrongly afraid of being sued if the victim dies. But under the Good Samaritan Law, Floridians are protected, and cannot face legal action for simply trying to help.
WATCH: Why are people hesitant to use an AED?
In J.R. Bourne's case, only three to four minutes passed before he was brought back to life, precious minutes that could have been his last if lifeguards didn't know where to find the AED.
"It's just being cognizant and people in the community should know about it. Take me for instance it could happen to people at any time," Bourne said.
Laws differ regarding AEDs, depending on where you live. See Florida statutes. See Georgia statues.