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Authenticity verified. More refinements More refinements Bring Home a Little Casino Fun With a Slot Machine Whether its to entertain your patrons and make a little money or just for you and your friends, a slot machine is a fun way to pass the time and makes a great addition to any man-cave.
What sorts of slot machines are there? Japanese Pachislo machines. Veteran fruit machines retired from good old British pubs. Antique penny slot arcade machines.
Toy versions of the full-size machines. What can you expect to pay for a slot machine? What if youre buying a second-hand machine?
All Auction Buy it now. Sort: Best Match. A hand pay could also be necessary as a result of a short pay.
Hopper fill slip is a document used to record the replenishment of the coin in the coin hopper after it becomes depleted as a result of making payouts to players.
The slip indicates the amount of coin placed into the hoppers, as well as the signatures of the employees involved in the transaction, the slot machine number and the location and the date.
MEAL book M achine e ntry a uthorization l og is a log of the employee's entries into the machine. Low-level or slant-top slot machines include a stool so the player may sit down.
Stand-up or upright slot machines are played while standing. Optimal play is a payback percentage based on a gambler using the optimal strategy in a skill-based slot machine game.
Payline is a line that crosses through one symbol on each reel, along which a winning combination is evaluated. Classic spinning reel machines usually have up to nine paylines, while video slot machines may have as many as one hundred.
Paylines could be of various shapes horizontal, vertical, oblique, triangular, zigzag, etc. Persistent state refers to passive features on some slot machines, some of which able to trigger bonus payouts or other special features if certain conditions are met over time by players on that machine.
Roll-up is the process of dramatizing a win by playing sounds while the meters count up to the amount that has been won. Short pay refers to a partial payout made by a slot machine, which is less than the amount due to the player.
This occurs if the coin hopper has been depleted as a result of making earlier payouts to players. The remaining amount due to the player is either paid as a hand pay or an attendant will come and refill the machine.
A scatter is a pay combination based on occurrences of a designated symbol landing anywhere on the reels, rather than falling in sequence on the same payline.
A scatter pay usually requires a minimum of three symbols to land, and the machine may offer increased prizes or jackpots depending on the number that land.
Scatters are frequently used to trigger bonus games, such as free spins with the number of spins multiplying based on the number of scatter symbols that land.
The scatter symbol usually cannot be matched using wilds, and some games may require the scatter symbols to appear on consecutive reels in order to pay.
On some multiway games, scatter symbols still pay in unused areas. Taste is a reference to the small amount often paid out to keep a player seated and continuously betting.
Only rarely will machines fail to pay even the minimum out over the course of several pulls. Tilt is a term derived from electromechanical slot machines' " tilt switches ", which would make or break a circuit when they were tilted or otherwise tampered with that triggered an alarm.
While modern machines no longer have tilt switches, any kind of technical fault door switch in the wrong state, reel motor failure, out of paper, etc.
A theoretical hold worksheet is a document provided by the manufacturer for every slot machine that indicates the theoretical percentage the machine should hold based on the amount paid in.
The worksheet also indicates the reel strip settings, number of coins that may be played, the payout schedule, the number of reels and other information descriptive of the particular type of slot machine.
Volatility or variance refers to the measure of risk associated with playing a slot machine. A low-volatility slot machine has regular but smaller wins, while a high-variance slot machine has fewer but bigger wins.
Weight count is an American term referring to the total value of coins or tokens removed from a slot machine's drop bucket or drop box for counting by the casino's hard count team through the use of a weigh scale.
Wild symbols substitute for most other symbols in the game similarly to a joker card , usually excluding scatter and jackpot symbols or offering a lower prize on non-natural combinations that include wilds.
How jokers behave are dependent on the specific game and whether the player is in a bonus or free games mode. Sometimes wild symbols may only appear on certain reels, or have a chance to "stack" across the entire reel.
Each machine has a table that lists the number of credits the player will receive if the symbols listed on the pay table line up on the pay line of the machine.
Some symbols are wild and can represent many, or all, of the other symbols to complete a winning line. Especially on older machines, the pay table is listed on the face of the machine, usually above and below the area containing the wheels.
On video slot machines, they are usually contained within a help menu, along with information on other features. Historically, all slot machines used revolving mechanical reels to display and determine results.
Although the original slot machine used five reels, simpler, and therefore more reliable, three reel machines quickly became the standard.
This limited the manufacturer's ability to offer large jackpots since even the rarest event had a likelihood of 0. Although the number of symbols eventually increased to about 22, allowing 10, combinations,  this still limited jackpot sizes as well as the number of possible outcomes.
In the s, however, slot machine manufacturers incorporated electronics into their products and programmed them to weight particular symbols.
Thus the odds of losing symbols appearing on the payline became disproportionate to their actual frequency on the physical reel.
A symbol would only appear once on the reel displayed to the player, but could, in fact, occupy several stops on the multiple reel.
In Inge Telnaes received a patent for a device titled, "Electronic Gaming Device Utilizing a Random Number Generator for Selecting the Reel Stop Positions" US Patent ,  which states: "It is important to make a machine that is perceived to present greater chances of payoff than it actually has within the legal limitations that games of chance must operate.
With microprocessors now ubiquitous, the computers inside modern slot machines allow manufacturers to assign a different probability to every symbol on every reel.
To the player it might appear that a winning symbol was "so close", whereas in fact the probability is much lower. In the s in the U. These used a number of features to ensure the payout was controlled within the limits of the gambling legislation.
As a coin was inserted into the machine, it could go either directly into the cashbox for the benefit of the owner or into a channel that formed the payout reservoir, with the microprocessor monitoring the number of coins in this channel.
The drums themselves were driven by stepper motors, controlled by the processor and with proximity sensors monitoring the position of the drums.
A "look-up table" within the software allows the processor to know what symbols were being displayed on the drums to the gambler.
This allowed the system to control the level of payout by stopping the drums at positions it had determined. If the payout channel had filled up, the payout became more generous; if nearly empty, the payout became less so thus giving good control of the odds.
Video slot machines do not use mechanical reels, instead of using graphical reels on a computerized display. As there are no mechanical constraints on the design of video slot machines, games often use at least five reels, and may also use non-standard layouts.
This greatly expands the number of possibilities: a machine can have 50 or more symbols on a reel, giving odds as high as million to 1 against — enough for even the largest jackpot.
As there are so many combinations possible with five reels, manufacturers do not need to weight the payout symbols although some may still do so.
Instead, higher paying symbols will typically appear only once or twice on each reel, while more common symbols earning a more frequent payout will appear many times.
Video slot machines usually make more extensive use of multimedia , and can feature more elaborate minigames as bonuses.
Modern cabinets typically use flat-panel displays , but cabinets using larger curved screens which can provide a more immersive experience for the player are not uncommon.
Video slot machines typically encourage the player to play multiple "lines": rather than simply taking the middle of the three symbols displayed on each reel, a line could go from top left to the bottom right or any other pattern specified by the manufacturer.
As each symbol is equally likely, there is no difficulty for the manufacturer in allowing the player to take as many of the possible lines on offer as desire — the long-term return to the player will be the same.
The difference for the player is that the more lines they play, the more likely they are to get paid on a given spin because they are betting more.
To avoid seeming as if the player's money is simply ebbing away whereas a payout of credits on a single-line machine would be bets and the player would feel they had made a substantial win, on a line machine, it would only be five bets and not seem as significant , manufacturers commonly offer bonus games, which can return many times their bet.
The player is encouraged to keep playing to reach the bonus: even if he is losing, the bonus game could allow then to win back their losses.
All modern machines are designed using pseudorandom number generators "PRNGs" , which are constantly generating a sequence of simulated random numbers, at a rate of hundreds or perhaps thousands per second.
As soon as the "Play" button is pressed, the most recent random number is used to determine the result. This means that the result varies depending on exactly when the game is played.
A fraction of a second earlier or later and the result would be different. It is important that the machine contains a high-quality RNG implementation.
Because all PRNGs must eventually repeat their number sequence  and, if the period is short or the PRNG is otherwise flawed, an advanced player may be able to "predict" the next result.
Having access to the PRNG code and seed values, Ronald Dale Harris , a former slot machine programmer, discovered equations for specific gambling games like Keno that allowed him to predict what the next set of selected numbers would be based on the previous games played.
Most machines are designed to defeat this by generating numbers even when the machine is not being played so the player cannot tell where in the sequence they are, even if they know how the machine was programmed.
This is known as the "theoretical payout percentage" or RTP, "return to player". The minimum theoretical payout percentage varies among jurisdictions and is typically established by law or regulation.
The winning patterns on slot machines — the amounts they pay and the frequencies of those payouts — are carefully selected to yield a certain fraction of the money paid to the "house" the operator of the slot machine while returning the rest to the players during play.
Within some EGM development organizations this concept is referred to simply as "par". Play now! A slot machine's theoretical payout percentage is set at the factory when the software is written.
Changing the payout percentage after a slot machine has been placed on the gaming floor requires a physical swap of the software or firmware , which is usually stored on an EPROM but may be loaded onto non-volatile random access memory NVRAM or even stored on CD-ROM or DVD , depending on the capabilities of the machine and the applicable regulations.
Based on current technology, this is a time-consuming process and as such is done infrequently. Other jurisdictions, including Nevada, randomly audit slot machines to ensure that they contain only approved software.
Historically, many casinos, both online and offline, have been unwilling to publish individual game RTP figures, making it impossible for the player to know whether they are playing a "loose" or a "tight" game.
Since the turn of the century some information regarding these figures has started to come into the public domain either through various casinos releasing them—primarily this applies to online casinos—or through studies by independent gambling authorities.
The return to player is not the only statistic that is of interest. The probabilities of every payout on the pay table is also critical.
For example, consider a hypothetical slot machine with a dozen different values on the pay table. However, the probabilities of getting all the payouts are zero except the largest one.
Also, most people would not win anything, and having entries on the paytable that have a return of zero would be deceptive.
As these individual probabilities are closely guarded secrets, it is possible that the advertised machines with high return to player simply increase the probabilities of these jackpots.
The added advantage is that these large jackpots increase the excitement of the other players. The table of probabilities for a specific machine is called the Probability and Accounting Report or PAR sheet, also PARS commonly understood as Paytable and Reel Strips.
Mathematician Michael Shackleford revealed the PARS for one commercial slot machine, an original International Gaming Technology Red White and Blue machine.
This game, in its original form, is obsolete, so these specific probabilities do not apply. He only published the odds after a fan of his sent him some information provided on a slot machine that was posted on a machine in the Netherlands.
The psychology of the machine design is quickly revealed. There are 13 possible payouts ranging from to 2, The payout comes every 8 plays.
The payout comes every 33 plays, whereas the payout comes every plays. Most players assume the likelihood increases proportionate to the payout.
The one mid-size payout that is designed to give the player a thrill is the payout. It is programmed to occur an average of once every plays.
The payout is high enough to create excitement, but not high enough that it makes it likely that the player will take their winnings and abandon the game.
In contrast the payout occurs only on average of once every 6, plays. The player who continues to feed the machine is likely to have several mid-size payouts, but unlikely to have a large payout.
He quits after he is bored or has exhausted his bankroll. Despite their confidentiality, occasionally a PAR sheet is posted on a website.
They have limited value to the player, because usually a machine will have 8 to 12 different possible programs with varying payouts.
In addition, slight variations of each machine e. The casino operator can choose which EPROM chip to install in any particular machine to select the payout desired.
The result is that there is not really such a thing as a high payback type of machine, since every machine potentially has multiple settings.
From October to February , columnist Michael Shackleford obtained PAR sheets for five different nickel machines; four IGT games Austin Powers , Fortune Cookie , Leopard Spots and Wheel of Fortune and one game manufactured by WMS; Reel 'em In.
Without revealing the proprietary information, he developed a program that would allow him to determine with usually less than a dozen plays on each machine which EPROM chip was installed.
Then he did a survey of over machines in 70 different casinos in Las Vegas. He averaged the data, and assigned an average payback percentage to the machines in each casino.
The resultant list was widely publicized for marketing purposes especially by the Palms casino which had the top ranking.
One reason that the slot machine is so profitable to a casino is that the player must play the high house edge and high payout wagers along with the low house edge and low payout wagers.
Other bets have a higher house edge, but the player is rewarded with a bigger win up to thirty times in craps. The player can choose what kind of wager he wants to make.
A slot machine does not afford such an opportunity. Theoretically, the operator could make these probabilities available, or allow the player to choose which one so that the player is free to make a choice.
However, no operator has ever enacted this strategy. Different machines have different maximum payouts, but without knowing the odds of getting the jackpot, there is no rational way to differentiate.
In many markets where central monitoring and control systems are used to link machines for auditing and security purposes, usually in wide area networks of multiple venues and thousands of machines, player return must usually be changed from a central computer rather than at each machine.
A range of percentages is set in the game software and selected remotely. In , the Nevada Gaming Commission began working with Las Vegas casinos on technology that would allow the casino's management to change the game, the odds, and the payouts remotely.
The change cannot be done instantaneously, but only after the selected machine has been idle for at least four minutes.
After the change is made, the machine must be locked to new players for four minutes and display an on-screen message informing potential players that a change is being made.
Some varieties of slot machines can be linked together in a setup sometimes known as a "community" game. The most basic form of this setup involves progressive jackpots that are shared between the bank of machines, but may include multiplayer bonuses and other features.
In some cases multiple machines are linked across multiple casinos. In these cases, the machines may be owned by the manufacturer, who is responsible for paying the jackpot.
The casinos lease the machines rather than owning them outright. Casinos in New Jersey, Nevada, and South Dakota now offer multi-state progressive jackpots, which now offer bigger jackpot pools.
Mechanical slot machines and their coin acceptors were sometimes susceptible to cheating devices and other scams. One historical example involved spinning a coin with a short length of plastic wire.
The weight and size of the coin would be accepted by the machine and credits would be granted. However, the spin created by the plastic wire would cause the coin to exit through the reject chute into the payout tray.
This particular scam has become obsolete due to improvements in newer slot machines. Another obsolete method of defeating slot machines was to use a light source to confuse the optical sensor used to count coins during payout.
Modern slot machines are controlled by EPROM computer chips and, in large casinos, coin acceptors have become obsolete in favor of bill acceptors.
These machines and their bill acceptors are designed with advanced anti-cheating and anti-counterfeiting measures and are difficult to defraud.
Early computerized slot machines were sometimes defrauded through the use of cheating devices, such as the "slider", "monkey paw", "lightwand" and "the tongue".
Malfunctioning electronic slot machines are capable of indicating jackpot winnings far in excess of those advertised. In the United States, the public and private availability of slot machines is highly regulated by state governments.