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Methods of manipulation in slot machines

Ever since gambling has existed, people have tried to outsmart the system using various scams. Dice were manipulated so that they displayed a given number and cards were marked or “marked” in order to give the player an advantage.

When commercial gambling was still in its infancy, the scammers were quite successful at it. Attempts are made to take advantage of the venues with increasingly tricky methods.

In the past, slot machines in particular offered a lot of vulnerability. With relatively simple tricks, fraudsters coaxed the money from the classic slots from Novoline, Merkur & Co., which at the time were still purely mechanical.

But over time, the technology developed further and the machine manufacturers integrated efficient protective measures that were supposed to protect against fraud.

However, the fraudsters' skills also developed. Resourceful inventors still manage to outsmart the slot machine games equipped with protective programs and bypass their security systems.

Terrestrial casinos and online casinos generate around 70 billion euros worldwide each year. Compared to the enormous sales generated by the arcades, the losses that the gambling companies lose through fraud are comparatively small. According to Worldwide Casino Consulting, a maximum of 0.1% of sales fall into the hands of the fraudsters. In most cases it is also possible to track down the fraudsters.

In the following, we will introduce you to some of the most common methods, some of which have even been used with success in the past. However, we do not recommend trying the tricks.

Casinos employ people whose main job is to protect the bank from fraud. It is practically her job to be familiar with scams and slot machine tips and tricks. If someone is caught cheating, the gambling operators are not squeamish about the person concerned.

The most common methods of slot machine manipulation

Coin on a string (yo-yo cheat) 

The trick with the coin attached to a string, also known as the “yo-yo cheat”, is one of the classic methods of manipulating a slot machine.

The coin is thrown into the slot of the device. A sensor detects that money has been inserted and the player can begin his game. However, he first pulls the coin out so that it can be used again. This trick no longer works today as the mechanical sensors have been replaced by electronic devices. 

Fake coins

The older generation of classic slot machines used a system that recorded the weight of the coin. Their value was determined analogously. Some scammers used counterfeit coins of the same weight made from similar metal.

One of the most famous scammers who used this trick was Louis "The Coin" Colavecchio, who used this scam for years to rob the casinos of a lot of money. He was finally arrested in 1998. After he was released in 2006, he continued cheating. However, he was caught again after a few months.

Polished coins

As gaming machine technology advanced, the devices incorporated both an optical sensor and a physical measuring device. When the coin is inserted, the optical sensor detects the coin. However, this sensor was not connected to the second measuring device.

Fraudsters threw in a plastic coin of the same size along with the coin that had been ground off on one side. Since the sensor could not recognize the milled coin, it was ejected again while the plastic chip remained in the machine and the game was started.

Coins replaced by player cards

The scams in which manipulated coins were used no longer work these days. Most gambling halls and casinos use player cards instead of cash.

The player card works in a similar way to the credit for the mobile network. The credit is topped up at the cash register or at a special ATM. Then the card is inserted into the slot provided and you play until the credit is used up. If winnings are made, these are credited to the card. The credit can be paid out at the cash register or on the device.

Cheating with the magnet

Magnet cheating was a method that worked when the reels of slot machines weren't electronically controlled, but rotated mechanically.

The cheater only had to hold a strong magnet in front of the spinning reels at the right moment to generate the desired winning combination. Today this method is no longer possible.

Slot machine manipulation with the piano string

In 1982 a group devised a plan to manipulate slot machines using a piano string at Caesars Boardwalk Regency Casino in Atlantic City. To do this, the device was first opened to attach the wire to the mechanism of the rollers. During the game, the piano string was pulled in order to get the desired winning combinations.

However, the team was filmed by the surveillance cameras taking a lot of money from the machine. Before the perpetrators could leave the best online casinos, they were arrested by the security forces.

Fraud using modern technology

When the technology of gaming devices developed further and simple tricks such as fake coins or the yo-yo trick were no longer applicable, resourceful inventors came up with other ideas to outsmart the slot machines.

Fraud with the bill validator

This scam involves wrapping a very small device on a $ 1 banknote. The slot machine is tricked into thinking that the player is depositing $ 100. This slot machine trick is said to have worked for a while.

Light wand

Tommy Glenn Carmichael manipulated the slot machines with his light wand. (Image:

Tommy Glenn Carmichael, one of the most notorious slot scammers, invented a light stick to trick the coin sensor. This rod was inserted into the coin slot. The flashing lights messed up the system so much that the machines turned small payouts into huge wins.

The video tells the story of Carmichael

The monkey paw

The so-called "monkey paw" is another invention of the con artist Carmichael. It was a curved metal rod to which a guitar string was attached. This was then inserted into the slot machine vent to grasp the coin funnel trigger switch and the coins were ejected.

Top-Bottom Joint (connection between top and bottom)

This manipulation method is probably one of the trickiest in casino history. It was particularly widespread in the 1970s and 1980s.

A special tool was used for this, which consisted of two parts, an upper and a lower part, which is where the name of the trick comes from. The upper part was a metal rod, the end of which was bent in the shape of a "q". The lower part was a long wire.

The upper part was attached to the money slot while the lower part was placed where the winnings are ejected. This created an electrical circuit that caused the machine to pay out the money.

Exchange of computer chips

Dennis Nikrasch exchanged the chips on the playground equipment. (Image:

Exchanging computer chips was another way of tampering with a slot machine. Dennis Nikrasch bought a slot machine and studied its inner workings. He found out how it worked and discovered its weak points in the process.

He had the idea of ​​reprogramming a chip and exchanging it for the chips in the machine. To do this, he put together a whole team of accomplices who managed to place the manipulated chips in the machine. In the period between 1976 and 1979, the scam team allegedly eased the casinos in Las Vegas by around USD 10 million.

Slot cheat code

In the 1990s, the Nevada Gaming Authority hired Ronald D. Harris. His job was to check the slot machine software in the state casinos for possible errors. His position enabled Harris to know the RNG source codes. It was no longer a problem for him to manipulate the codes to his advantage.

Together with his accomplice Reid McNeal, they planned to coax only a few thousand dollars from the machine each night so as not to attract any attention. But one day they were too greedy. A $ 100,000 win at the Bally's Park Place Hotel in Atlantic City drew management's attention, resulting in a raid of Harris's room. Police investigators found the equipment there.

Manipulation with the smartphone: From Russia With "Cheats"

A most spectacular case of slot machine manipulation occurred in 2014. A St. Louis casino found that some machines had paid out more than usual. When reviewing the video footage, the casino's security staff found that the same man was always making high profits.

They also observed that the man held his iPhone close to the screen, that all of the devices were Aristocrat machines and that after a pause he suddenly pressed the spin button. It soon became apparent that other casinos had fallen victim to slot machine manipulation and that the same man was involved.

The authorities found the man named Murat Bilev. Further investigation revealed that he was a member of a Russian team that drove millions of dollars over several casinos in the US and Macau.

The hacking team had previously determined how the RNG of the Aristocrat machines worked and developed a hacking app. This software predicted exactly when the button had to be pressed in order to receive a payout.


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