Slot Machine Expected Value

Dan from Communication Group 34 takes you through the rules and mathematics of Casino slot Machines!Hub Video: https://www.youtube.com/watch?v=bOl-ycNvSE. Every slot machine has a predetermined payout percentage. When you hear things like 'our slots pay back 98.3%' this means that over the long-term for every dollar inserted in the machine, it will return 98.3 cents.

1. Slot Machine Expected Value Calculator
2. Slot Machine Expected Values
3. Slot Machine Expected Value Formula
4. Slot Machine Expected Value Calculation

Loops are R’s method for repeating a task, which makes them a useful tool for programming simulations. This chapter will teach you how to use R’s loop tools.

Let’s use the score function to solve a real-world problem.

Your slot machine is modeled after real machines that were accused of fraud. The machines appeared to pay out 40 cents on the dollar, but the manufacturer claimed that they paid out 92 cents on the dollar. You can calculate the exact payout rate of your machine with the score program. The payout rate will be the expected value of the slot machine’s prize.

11.1 Expected Values

The expected value of a random event is a type of weighted average; it is the sum of each possible outcome of the event, weighted by the probability that each outcome occurs:

[E(x) = sum_{i = 1}^{n}left( x_{i} cdot P(x_{i}) right)]

You can think of the expected value as the average prize that you would observe if you played the slot machine an infinite number of times. Let’s use the formula to calculate some simple expected values. Then we will apply the formula to your slot machine.

Do you remember the die you created in Project 1: Weighted Dice?

Each time you roll the die, it returns a value selected at random (one through six). You can find the expected value of rolling the die with the formula:

[E(text{die}) = sum_{i = 1}^{n}left( text{die}_{i} cdot P(text{die}_{i}) right)]

The (text{die}_{i})s are the possible outcomes of rolling the die: 1, 2, 3, 4, 5, and 6; and the (P(text{die}_{i}))’s are the probabilities associated with each of the outcomes. If your die is fair, each outcome will occur with the same probability: 1/6. So our equation simplifies to:

[begin{array}{rl}E(text{die}) & = sum_{i = 1}^{n}left( text{die}_{i} cdot P(text{die}_{i}) right)& = 1 cdot frac{1}{6} + 2 cdot frac{1}{6} + 3 cdot frac{1}{6} + 4 cdot frac{1}{6} + 5 cdot frac{1}{6} + 6 cdot frac{1}{6}& = 3.5end{array}]

Hence, the expected value of rolling a fair die is 3.5. You may notice that this is also the average value of the die. The expected value will equal the average if every outcome has the same chance of occurring.

But what if each outcome has a different chance of occurring? For example, we weighted our dice in Packages and Help Pages so that each die rolled 1, 2, 3, 4, and 5 with probability 1/8 and 6 with probability 3/8. You can use the same formula to calculate the expected value in these conditions:

[begin{array}{rl} E(die) & = 1 cdot frac{1}{8} + 2 cdot frac{1}{8} + 3 cdot frac{1}{8} + 4 cdot frac{1}{8} + 5 cdot frac{1}{8} + 6 cdot frac{3}{8} & = 4.125 end{array} ]

Hence, the expected value of a loaded die does not equal the average value of its outcomes. If you rolled a loaded die an infinite number of times, the average outcome would be 4.125, which is higher than what you would expect from a fair die.

Notice that we did the same three things to calculate both of these expected values. We have:

• Listed out all of the possible outcomes
• Determined the value of each outcome (here just the value of the die)
• Calculated the probability that each outcome occurred

The expected value was then just the sum of the values in step 2 multiplied by the probabilities in step 3.

You can use these steps to calculate more sophisticated expected values. For example, you could calculate the expected value of rolling a pair of weighted dice. Let’s do this step by step.

First, list out all of the possible outcomes. A total of 36 different outcomes can appear when you roll two dice. For example, you might roll (1, 1), which notates one on the first die and one on the second die. Or, you may roll (1, 2), one on the first die and two on the second. And so on. Listing out these combinations can be tedious, but R has a function that can help.

11.2 expand.grid

The expand.grid function in R provides a quick way to write out every combination of the elements in n vectors. For example, you can list every combination of two dice. To do so, run expand.grid on two copies of die:

expand.grid will return a data frame that contains every way to pair an element from the first die vector with an element from the second die vector. This will capture all 36 possible combinations of values:

You can use expand.grid with more than two vectors if you like. For example, you could list every combination of rolling three dice with expand.grid(die, die, die) and every combination of rolling four dice with expand.grid(die, die, die, die), and so on. expand.grid will always return a data frame that contains each possible combination of n elements from the n vectors. Each combination will contain exactly one element from each vector.

You can determine the value of each roll once you’ve made your list of outcomes. This will be the sum of the two dice, which you can calculate using R’s element-wise execution:

R will match up the elements in each vector before adding them together. As a result, each element of value will refer to the elements of Var1 and Var2 that appear in the same row.

Next, you must determine the probability that each combination appears. You can calculate this with a basic rule of probability:

The probability that n independent, random events all occur is equal to the product of the probabilities that each random event occurs.

Or more succinctly:

[P(A & B & C & ...) = P(A) cdot P(B) cdot P(C) cdot ...]

So the probability that we roll a (1, 1) will be equal to the probability that we roll a one on the first die, 1/8, times the probability that we roll a one on the second die, 1/8:

[begin{array}{rl}P(1 & 1) & = P(1) cdot P(1) & = frac{1}{8} cdot frac{1}{8}& = frac{1}{64}end{array}]

And the probability that we roll a (1, 2) will be:

[begin{array}{rl}P(1 & 2) & = P(1) cdot P(2) & = frac{1}{8} cdot frac{1}{8}& = frac{1}{64}end{array}]

And so on.

Let me suggest a three-step process for calculating these probabilities in R. First, we can look up the probabilities of rolling the values in Var1. We’ll do this with the lookup table that follows:

If you subset this table by rolls$Var1, you will get a vector of probabilities perfectly keyed to the values of Var1:

Second, we can look up the probabilities of rolling the values in Var2:

Third, we can calculate the probability of rolling each combination by multiplying prob1 by prob2:

It is easy to calculate the expected value now that we have each outcome, the value of each outcome, and the probability of each outcome. The expected value will be the summation of the dice values multiplied by the dice probabilities:

So the expected value of rolling two loaded dice is 8.25. If you rolled a pair of loaded dice an infinite number of times, the average sum would be 8.25. (If you are curious, the expected value of rolling a pair of fair dice is 7, which explains why 7 plays such a large role in dice games like craps.)

Now that you’ve warmed up, let’s use our method to calculate the expected value of the slot machine prize. We will follow the same steps we just took:

• We will list out every possible outcome of playing the machine. This will be a list of every combination of three slot symbols.
• We will calculate the probability of getting each combination when you play the machine.
• We will determine the prize that we would win for each combination.

When we are finished, we will have a data set that looks like this:

The expected value will then be the sum of the prizes multiplied by their probability of occuring:

[E(text{prize}) = sum_{i = 1}^{n}left( text{prize}_{i} cdot P(text{prize}_{i}) right)]

Ready to begin?

Be sure to add the argument stringsAsFactors = FALSE to your expand.grid call; otherwise, expand.grid will save the combinations as factors, an unfortunate choice that will disrupt the score function.

Now, let’s calculate the probability of getting each combination. You can use the probabilities contained in the prob argument of get_symbols to do this. These probabilities determine how frequently each symbol is chosen when your slot machine generates symbols. They were calculated after observing 345 plays of the Manitoba video lottery terminals. Zeroes have the largest chance of being selected (0.52) and cherries the least (0.01):

Now let’s look up our probabilities.

Now how should we calculate the total probability of each combination? Our three slot symbols are all chosen independently, which means that the same rule that governed our dice probabilities governs our symbol probabilities:

[P(A & B & C & ...) = P(A) cdot P(B) cdot P(C) cdot ...]

Exercise 11.4 (Calculate Probabilities for Each Combination) Calculate the overall probabilities for each combination. Save them as a column named prob in combos, then check your work.

You can check that the math worked by summing the probabilities. The probabilities should add up to one, because one of the combinations must appear when you play the slot machine. In other words, a combination will appear, with probability of one.

You can calculate the probabilities of every possible combination in one fell swoop with some element-wise execution:

The sum of the probabilities is one, which suggests that our math is correct:

You only need to do one more thing before you can calculate the expected value: you must determine the prize for each combination in combos. You can calculate the prize with score. For example, we can calculate the prize for the first row of combos like this:

However there are 343 rows, which makes for tedious work if you plan to calculate the scores manually. It will be quicker to automate this task and have R do it for you, which you can do with a for loop.

11.3 for Loops

A for loop repeats a chunk of code many times, once for each element in a set of input. for loops provide a way to tell R, “Do this for every value of that.” In R syntax, this looks like:

The that object should be a set of objects (often a vector of numbers or character strings). The for loop will run the code in that appears between the braces once for each member of that. For example, the for loop below runs print('one run') once for each element in a vector of character strings:

The value symbol in a for loop acts like an argument in a function. The for loop will create an object named value and assign it a new value on each run of the loop. The code in your loop can access this value by calling the value object.

What values will the for loop assign to value? It will use the elements in the set that you run the loop on. for starts with the first element and then assigns a different element to value on each run of the for loop, until all of the elements have been assigned to value. For example, the for loop below will run print(value) four times and will print out one element of c('My', 'second', 'for', 'loop') each time:

On the first run, the for loop substituted 'My' for value in print(value). On the second run it substituted 'second', and so on until for had run print(value) once with every element in the set:

If you look at value after the loop runs, you will see that it still contains the value of the last element in the set:

I’ve been using the symbol value in my for loops, but there is nothing special about it. You can use any symbol you like in your loop to do the same thing as long as the symbol appears before in in the parentheses that follow for. For example, you could rewrite the previous loop with any of the following:

Choose your symbols carefully

R will run your loop in whichever environment you call it from. This is bad news if your loop uses object names that already exist in the environment. Your loop will overwrite the existing objects with the objects that it creates. This applies to the value symbol as well.

For loops run on sets

In many programming languages, for loops are designed to work with integers, not sets. You give the loop a starting value and an ending value, as well as an increment to advance the value by between loops. The for loop then runs until the loop value exceeds the ending value.

You can recreate this effect in R by having a for loop execute on a set of integers, but don’t lose track of the fact that R’s for loops execute on members of a set, not sequences of integers.

for loops are very useful in programming because they help you connect a piece of code with each element in a set. For example, we could use a for loop to run score once for each row in combos. However, R’s for loops have a shortcoming that you’ll want to know about before you start using them: for loops do not return output.

for loops are like Las Vegas: what happens in a for loop stays in a for loop. If you want to use the products of a for loop, you must write the for loop so that it saves its own output as it goes.

Our previous examples appeared to return output, but this was misleading. The examples worked because we called print, which always prints its arguments in the console (even if it is called from a function, a for loop, or anything else). Our for loops won’t return anything if you remove the print call:

To save output from a for loop, you must write the loop so that it saves its own output as it runs. You can do this by creating an empty vector or list before you run the for loop. Then use the for loop to fill up the vector or list. When the for loop is finished, you’ll be able to access the vector or list, which will now have all of your results.

Let’s see this in action. The following code creates an empty vector of length 4:

The next loop will fill it with strings:

This approach will usually require you to change the sets that you execute your for loop on. Instead of executing on a set of objects, execute on a set of integers that you can use to index both your object and your storage vector. This approach is very common in R. You’ll find in practice that you use for loops not so much to run code, but to fill up vectors and lists with the results of code.

Let’s use a for loop to calculate the prize for each row in combos. To begin, create a new column in combos to store the results of the for loop:

The code creates a new column named prize and fills it with NAs. R uses its recycling rules to populate every value of the column with NA.

After you run the for loop, combos$prize will contain the correct prize for each row. This exercise also tests the score function; score appears to work correctly for every possible slot combination:

We’re now ready to calculate the expected value of the prize. The expected value is the sum of combos$prize weighted by combos$prob. This is also the payout rate of the slot machine:

Uh oh. The expected prize is about 0.54, which means our slot machine only pays 54 cents on the dollar over the long run. Does this mean that the manufacturer of the Manitoba slot machines was lying?

No, because we ignored an important feature of the slot machine when we wrote score: a diamond is wild. You can treat a DD as any other symbol if it increases your prize, with one exception. You cannot make a DD a C unless you already have another C in your symbols (it’d be too easy if every DD automatically earned you $2).

The best thing about DDs is that their effects are cumulative. For example, consider the combination B, DD, B. Not only does the DD count as a B, which would earn a prize of $10; the DD also doubles the prize to $20.

Adding this behavior to our code is a little tougher than what we have done so far, but it involves all of the same principles. You can decide that your slot machine doesn’t use wilds and keep the code that we have. In that case, your slot machine will have a payout rate of about 54 percent. Or, you could rewrite your code to use wilds. If you do, you will find that your slot machine has a payout rate of 93 percent, one percent higher than the manufacturer’s claim. You can calculate this rate with the same method that we used in this section.

Exercise 11.6 (Challenge) There are many ways to modify score that would count DDs as wild. If you would like to test your skill as an R programmer, try to write your own version of score that correctly handles diamonds.

If you would like a more modest challenge, study the following score code. It accounts for wild diamonds in a way that I find elegant and succinct. See if you can understand each step in the code and how it achieves its result.

To update the expected value, just update combos$prize:

Then recompute the expected value:

This result vindicates the manufacturer’s claim. If anything, the slot machines seem more generous than the manufacturer stated.

11.4 while Loops

R has two companions to the for loop: the while loop and the repeat loop. A while loop reruns a chunk while a certain condition remains TRUE. To create a while loop, follow while by a condition and a chunk of code, like this:

while will rerun condition, which should be a logical test, at the start of each loop. If condition evaluates to TRUE, while will run the code between its braces. If condition evaluates to FALSE, while will finish the loop.

Why might condition change from TRUE to FALSE? Presumably because the code inside your loop has changed whether the condition is still TRUE. If the code has no relationship to the condition, a while loop will run until you stop it. So be careful. You can stop a while loop by hitting Escape or by clicking on the stop-sign icon at the top of the RStudio console pane. The icon will appear once the loop begins to run.

Like for loops, while loops do not return a result, so you must think about what you want the loop to return and save it to an object during the loop.

You can use while loops to do things that take a varying number of iterations, like calculating how long it takes to go broke playing slots (as follows). However, in practice, while loops are much less common than for loops in R:

11.5 repeat Loops

repeat loops are even more basic than while loops. They will repeat a chunk of code until you tell them to stop (by hitting Escape) or until they encounter the command break, which will stop the loop.

You can use a repeat loop to recreate plays_till_broke, my function that simulates how long it takes to lose money while playing slots:

11.6 Summary

You can repeat tasks in R with for, while, and repeat loops. To use for, give it a chunk of code to run and a set of objects to loop through. for will run the code chunk once for each object. If you wish to save the output of your loop, you can assign it to an object that exists outside of the loop.

Repetition plays an important role in data science. It is the basis for simulation, as well as for estimates of variance and probability. Loops are not the only way to create repetition in R (consider replicate for example), but they are one of the most popular ways.

Unfortunately, loops in R can sometimes be slower than loops in other languages. As a result, R’s loops get a bad rap. This reputation is not entirely deserved, but it does highlight an important issue. Speed is essential to data analysis. When your code runs fast, you can work with bigger data and do more to it before you run out of time or computational power. Speed will teach you how to write fast for loops and fast code in general with R. There, you will learn to write vectorized code, a style of lightning-fast code that takes advantage of all of R’s strengths.

If you have a slot machine or you have bought one old used vintage slot machine and want to have some fixes to get it work then obviously you will think you need a machine technician. Many of you will even think of taking it to some repair station to get things done. But here in the guide you will find some of the repairs that you yourself can do with your slot machine and you need not need to join machine technical repair training school.

Like any other machines Slot machines too are a blend of electronic and mechanical components, that wear with age and require routine repairs. Before you begin to repair yourself do note that every slot machine that you have purchased whether old or new comes with installation and user guide manual. You need to read that many a times until you are familiar with each components and parts of the slot machine and understand thoroughly as how the slot machine works.

In your guide to repair slot machines you will find some common repairs that can be carried out by you, some videos to watch as well. If your slot machine has some complex issue then obviously you require a qualified technician.

Changing the Top Florescent Light

The top florescent light bulb is easily changed by following these simple procedures. The replacement bulb is an F15T8/CW 18″ 15 Watt bulb which is available at most hardware and department stores or may be purchased online at Ebay or Amazon or realslotmachinesforsale under the category ‘parts of slot machine’.

• Open the main slot machine door and ensure the door is fully open. Turn off the power to the slot machine. The power switch can be found with the main door open about midway down on the right side just inside the machine.
• If the machine is equipped with a top ticket printer, you must pull the bottom of the printer out far enough to see where the ticket paper is located, and note the area large enough to place a couple of your left fingers under.

• Remove the top metal trim strip which is a cover plate to the right of the ticket printer and/or is located along the bottom of the top glass. There are a couple of clips on the back of the metal trim strip that fit into notches on metal bracket which holds the top glass. The metal trim strip should be lifted upwards and outwards to remove.
• Once the metal trim strip is removed, the next step is to remove the top glass. Note that some top metal trim strips have a slot in the top that holds the top glass and they must be removed very carefully as to not damage or drop the top glass.

• You can now see the top glass is held in place by usually two or three clips that rise above the metal bracket behind the top metal trim strip. Now slowly lift up on the top glass from both bottom edges until the top glass until it is high enough to gently pull it forward and allowing it to slide down and away from the top track and clips holding it in place.
• Once the top glass has been removed, put it somewhere where it will not get knocked over or broken. You will see the florescent bulb in the middle of the top box area of the machine. Care should be taken removing the bulb as it may be very hot. Remove the old bulb by twisting the florescent tube about a quarter to half turn allowing the two prongs on the bulb to slide out of the fixture on both sides of the bulb.

• Remove and discard the old bulb. To install the new bulb, align the two prongs on each side of the florescent tube with the slits on each fixture in the top box of the slot machine. Twist the bulb into place normally using about a quarter to half of a turn. If the bulb is not secure or aligned, repeat the procedure.
• If your slot machine is an IGT S Plus machine, it is equipped with a florescent bulb starter. Then you can replace the starter when replacing the florescent light bulb. The starter is an FS-U Universal Starter. They are available at most hardware and department stores or may be ordered online too. The starter for the top florescent bulb on an IGT S Plus machine is located directly behind the florescent bulb fixture on the left side of the slot machine in the top box area.
• It is replaced by twisting about a quarter to half a turn as it is held in place with a bayonet type mount. Remove the old starter and discard. Replace with a new FS-U Universal Starter by aligning the two pins on the bottom of the starter with the notches in the starter receptacle, pushing it up into the starter socket, and then twisting it a quarter to half a turn into place.
• Prior to re-installing the top glass, turn the power switch on the right inside of the machine on to verify the bulb works properly. If it does not, turn the power off and check that the bulb is properly installed and secure. If replacing a starter, check that it is also properly installed and secure.
• After verifying the bulb is working, it is now time to replace the top glass. If your slot machine has a top ticket printer, ensure the ticket printer is still pulled out so you can place your fingers in the opening while replacing the top glass.
• Carefully and slowly lift up the top glass placing each hand under the bottom of the top glass. Slide it into the upper edge track on the top box of the slot machine carefully lifting it so it slides into the tracks while being able to push the top glass back far enough to clear the two or three raised clips on the metal bracket where the top glass holding track is located.
• Gently and slowly lower the top glass behind the clips so as to allow them to hold the glass in place. If properly secured, the top glass will not be able to slide down or out of its position. Keep a secure hold on the top glass until you are certain it is secured in the proper position.
• Replace the top metal trim strip by aligning the two or three hooks the back through the metal bracket that supports and holds the top glass. Once the hooks on the back are in place, gently push the top metal trim strip down and it should snap into place. If you have a slot machine with a top ticket printer, close it tight into position. Close the main slot machine door and you are ready to play.

Changing the Belly Glass Florescent Light

The belly glass florescent light bulb is easily changed by following these simple procedures. The replacement bulb is an F15T8/CW 18″ 15 Watt bulb which is available at most hardware and department stores or may be bought online as spare parts of slot machine.

• Open the main slot machine door. Turn off the power to the slot machine. The power switch can be found with the main door open about midway down on the right side just inside the machine.
• Facing the slot machine door, look on the right side of the door just around from bill acceptor area. You will see a knob sticking out that is approximately the size of the end of a regular pencil. This knob when pulled out releases the slot machine belly glass assembly (belly door) to fold down so the bulb can be accessed.

• There are a couple of very important thing to remember prior to pulling this knob to release the belly door. First try pulling gently on the knob. If it does not allow you to pull out and you have a lock installed directly above it, the lock must unlocked in order to allow the release knob to pull out. When pulling out the release knob, be ready for the belly door to fold down.
• Most of the time you must lightly pull on both sides of the belly door to get it to fold down, however always place your hand under it so it does not fall down too quickly causing the belly glass to break or crack.
• Once the belly door is in the down position, you will see the access to the florescent bulb bracket that is held in place by a small Phillips screw. Remove the screw and place it the coin tray so it will be handy when you need it after replacing the bulb.

• The long metal bracket that holds the florescent bulb must be slid slightly right or left so as to be able to lift it out of the belly door. Gently lift the metal bracket with florescent bulb out of the assembly far to be able to turn it over to replace the bulb. Be cautious as the bulb could still be hot!
• Grasp the metal bracket holding the florescent bulb and remove the old bulb by twisting the florescent tube about a quarter to half turn allowing the two prongs on the bulb to slide out of the fixture on both sides of the bulb.

• Remove and discard the old bulb.To install the new bulb, align the two prongs on each side of the florescent tube with the slits on each fixture that is on each side of the new bulb. Twist the bulb into place normally using about a quarter to half of a turn. If the bulb is not secure or aligned, repeat the procedure.
• Now turn the metal bracket that holds the newly installed bulb over and back into position in the belly glass assembly. Slid the bracket slightly right or left into position and replace the small screw which holds the metal bracket in place.
• If your slot machine is an IGT S Plus machine, it is equipped with a florescent bulb starter. So you need to replace the starter a well when replacing the florescent light bulb. The starter is an FS-U Universal Starter. They are available online and you can purchase one.
• The starter for the belly glass florescent bulb is located on the back of the main slot machine door on the lower right hand corner as you face the back of the door.

• It is replaced by twisting about a quarter to half a turn as it is held in place with a bayonet type mount. Remove the old starter and discard. Replace with a new FS-U Universal Starter by aligned the two notches on the bottom of the starter, pushing it into the starter socket, and then twisting it a quarter to half a turn into place.
• Prior to closing the belly glass door, turn the power switch on the right inside of the machine on to verify the bulb works properly. If it does not, turn the power off and check that the bulb is properly installed and secure. Also check to ensure the starter is properly installed and secured.
• Lift the belly glass assembly up and push it into place in the slot machine door. Ensure the belly glass door snaps into place and the knob on the side of the door is in its normal position. It is spring loaded so as to not allow the belly glass assembly to open unless it pulled. If the belly door appears to be in place, pull on both sides of the belly door to make sure it is locked and secure.
• If you unlocked the lock above the knob, re-lock it. Close the main slot machine door and you are ready to use your slot machine.

Changing the Push Button Bulbs

All of the slot machine’s push button lights such Play Max Credits, Spin Reels, Bet One Credit, etc. are easily replaced by following this simple procedure. The replacement bulbs are #161 on IGT S2000 machines and #555 on IGT S+ machines and may be purchased from online stores.

• Fully open the slot machine door. Look on the backside of the door. Each push button will extend down from the shelf on the door and will have a small wire bundle going to it. Identify which push button bulb needs to be replaced.
• Carefully pull down on the bottom of the push button area that is normally white and is where you will see wiring connected. Using your thumb and two fingers, pull straight down and the bottom portion of the push button should snap out.

• You will now be able to see the bulb in the top area of the lower push button assembly. Use caution as the bulb may be very hot. Pull the wedge bulb out and discard it. Notice the slot in which the bulb located.
• Place a new bulb in the slot noting the direction of slot ensuring the new wedge bulb is inserted so as to line up in the slot. Push the new bulb into place.

• Replace the bottom of the push button assembly by inserting it into the top portion of the push button assembly. The bottom portion will snap into position. Ensure that none of the wire connections have been accidentally knocked loose on the bottom of the push button. Note the push button light will not illuminate until the slot machine door is closed. Close the main slot machine door and you are ready to play.

Changing the Small Panel Lights

The small panel lights that illuminate the denomination amount and other areas behind the glass are easily changed. For denomination amount lights on the IGT S2000, a #73 bulb is needed and a #86 bulb is needed on the IGT S+ slot machines. They may be bought online from slot machine selling sites.

Here it is described as how to change the lights behind denomination amounts such as .25 Cents. Other small panel light bulbs are changed in the same manner.

• Fully open the slot machine door. Look on the backside of the door. Note the location where the denomination amount would be located near the center just below the slot machine’s center glass. The area will appear to be flat with a small bulb holder projecting out that is slightly larger in diameter than a regular pencil and is flat on two or four sides.

• This bulb holder is removed by simply twisting it a quarter to half a turn and then gently pulling it out of its socket. It is held in place by somewhat of a bayonet type mount.
• Once the bulb holder is removed, pull the wedge bulb out of the socket and discard the old bulb. Caution should be taken as the old bulb may be very hot. Replace the bulb by firmly inserting a new bulb into the socket of the bulb holder being careful to align the wedge bulb correctly into the slot.
• Take the bulb holder and look for two notches on each side of the opening where the bulb holder is inserted. Note there are two notches on the bulb holder. Align the notches inserting the bulb holder into the panel.
• Gently twist the bulb holder about a quarter to half a turn to lock it into place. Verify the bulb is illuminating, and if not repeat the procedure using a different new bulb. Now close the main slot machine door and ready to use.

Cleaning Your Slot Machine

This is common thing and all you need is usually nothing more than a damp cloth to clean the exterior cabinet of your slot machine. Never use any abrasive or ammonia based cleaners on the cabinet of the machine.

The slot machine top, center and belly glasses may all be cleaned on the outside by using a window cleaner. However if you own a slot machine with a frosted exterior glass or one that has any exterior decorated markings such as stars, a window cleaner should not be used as the cleaner may damage the exterior images. Care should be taken cleaning interior glass as a cleaner and cloth may damage labels or markings.

The inside of the slot machine should not require cleaning other than occasionally removing dust. This can normally be done with a damp clean cloth, however ensure the power switch has been turned off prior to cleaning.

When wiping dust inside your machine, be careful not to loosen any wires or connections. Do not use a damp cloth on the face of your reel strips as the playing symbols on the reel strips could come off or become torn. Also be very careful not to touch the back side of your reel strips with a damp cloth especially if the back sides of the reel strips are black. This can cause damage to this type reel strip.

When your Slot Machine Doesn’t Power On

When you get a slot machine and wish to locate or set up at your place, determine the household 120V AC outlet you are planning to use has power. Keep in mind some outlets are controlled on and off by a wall switch.

• With the slot machine unplugged from the outlet and surge protector, open the slot machine main door. Remove the coin tray by lifting up and pulling out the tray. Simply pull it out and down to remove the tray.

• The hopper is on the bottom floor of the machine and slides out on two base rails along two metal guides. Slide the hopper out slowly by grasping the handle with your left hand and supporting the hopper with your right hand. Do not use the black hopper bowl to pull the hopper out of the slot machine.
• On the lower right corner of the slot machine you should see the black power cord coming into the machine. The power cord plugs into the Power Distribution Unit which is located on the back wall of the slot machine.
• Verify the power cord is firmly plugged into place into the right side of the Power Distribution Unit.

• Place the hopper back into the slot machine making sure it slides in easily and completely with the base rails on hopper guides on the bottom of the machine. The hopper plugs into a receptacle toward the back of the machine. It is designed to fit in easily without using excessive force.
• The coin tray can be easily put back into place by ensuring the alignment pins on the coin tray match up to the top alignment holes on the bottom side of the machine. The tray should be pushed down into place. Make sure the tray is even when pushed into place. If the coin tray is not aligned and even, remove the coin tray, and repeat the procedure.
• Verify the power cord is firmly plugged into a good surge protector. Plug the end of surge protector into the outlet you have verified is good, and make sure the on/off switch on the surge protector is turned on.
• Now turn the power switch on the inside right of the slot machine to the on position and verify the slot machine is powered on by lights illuminating.

Slot Machine Expected Value Calculator

Jackpot Payout Reset

When your slot machine just hit a 25,000 credit Jackpot it now needs to be reset to continue playing. Depending on the model slot machine you have and the amount of the payout will determine the best course of action.

If you have an IGT S+ Slot Machine and your win is under the maximum payout amount specified on the center glass of the machine, the hopper may run out of coins or tokens. This is normally displayed by Error Code 3300. In this case it usually a simple matter of taking the coins or tokens that have been paid out and putting them back in the hopper allowing it to fully pay out. However, if you won a large jackpot that is “hand pay out”, then follow the steps below.

• First open the main slot machine door. Locate the Jackpot Key which is normally kept inside the slot machine in a plastic envelope on the side of the cash box. If you do not find it inside the machine, often times the Jackpot Key will be strapped with the main slot machine door key. It is a small key as pictured below.
• Take the key in hand and locate the jackpot reset which is a keyhole located on the right side of the slot machine. It is normally about two-thirds up from the bottom of the machine.

Slot Machine Expected Values

• Insert the Jackpot Reset Key into the keyhole. Turn the key only one quarter turn to the right. This will reset the machine, and once you close the main slot machine door, you will be ready to resume play.
• Note that if you turn the Jackpot reset key multiple times you may place your slot machine into a test mode and will thus delay your ability to continue playing.

Some of the Error Codes you get on Slot Machine

Error Code 3300 (IGT S+ Machines)

Simply put Error Code 3300 is normally telling you your hopper is low on or completely out of coins or tokens.

Open the main slot machine door. Look into the hopper. If it is empty or has just a few coins or tokens, place about 500 coins or tokens back into the hopper. Close the main slot machine door. In a few moments you should hear the sound of the hopper’s motor turning and soon the remaining coin payout will begin.

Error Code 3100 (IGT S+ Machines)

Error Code 3100 (Extra Coin Out Tilt) normally signifies either a jammed/stuck coin or token in the coin-out chute on the hopper, or the hopper coin-out sensor has detected the hopper may have paid out an extra coin.

• Open the main slot machine door. Remove the coin tray by lifting up and pulling out the tray. Simply pull it out and down to remove the tray.
• The hopper is on the bottom floor of the machine and slides out on two base rails along two metal guides. Slide the hopper out slowly by grasping the handle with your left hand and supporting the hopper with your right hand. Do not use the black hopper bowl to pull the hopper out of the slot machine.
• Inspect the hopper to determine if any coins/tokens appear to stuck or jammed in the hopper knife or the hopper coin-out channel.
• If a coin appears to be stuck or jammed, empty the hopper of coins/tokens for easier access to clearing the jammed coin/token.
• Once the stuck or jammed coin has been removed, place the hopper back into the slot machine making sure it slides in easily and completely with the base rails on hopper guides on the bottom of the machine. The hopper plugs into a receptacle toward the back of the machine. It is designed to fit in easily without using excessive force
• Refill the hopper with the proper size coins or tokens. The coin tray can be easily put back into place by ensuring the alignment pins on the coin tray match up to the top alignment holes on the bottom side of the machine. The tray should be pushed down into place. Make sure the tray is even when pushed into place. If the coin tray is not aligned and even, remove the coin tray, and repeat the procedure.
• Close the main slot machine door. The error code should be gone and the machine is ready to play.

Error Code 12 (IGT S+ Machines)

The 3.6 volt battery on the slot machine CPU Board normally lasts for years. However when an Error Code 12 is displayed, this is an indication the battery voltage has dropped below 2.9 volts and is now a low battery.

It is recommended to replace the battery as soon as possible. They can be purchased online from ebay, amazon or realslotmachinesforsale. When ordering a replacement battery, they will provide you with detailed instructions on how to change this battery which is located on the slot machine’s CPU Board.

In order to reset Error Code 12 temporarily, simply open and close the main slot machine door. It is important not to wait for a long time to replace the battery as data stored on the RAM may be lost. Replace the battery Asap.

Following are some of the other error codes that might interest you to solve your problem in repairing the slot machine

CODE	DESCRIPTION	PROBLEM
12	Low Battery	Battery voltage on processor board has dropped below 2.9 volts DC
21	Coin-In Tilt	Optic coin-in sensors were blocked
3100	Extra Coin Out	Stuck/jammed coin in hopper or optic sensor detects extra coin paid
3200	Coin-Out Tilt	Hopper coin-out sensor was blocked
3300	Hopper Empty	Hopper coin-out sensor sensor detects no coins were dispensed for 8 seconds or more. Hopper needs to be refilled with coins/tokens.
41	Reel #1	Tilt Designated reel is misaligned or malfunctioning
42	Reel # 2 Tilt	Designated reel is misaligned or malfunctioning
43	Reel #3	Tilt Designated reel is misaligned or malfunctioning
44	Reel #4	Tilt Designated reel is misaligned or malfunctioning
45	Reel #5 Tilt	Designated reel is misaligned or malfunctioning
49	Reel Mechanism Disconnected	A reel mechanism has become unplugged or the circuit is interrupted
61	CMOS RAM	Bad CMOS RAM data or data was cleared
62-0	Bad Game EPROM	Game program or data program check
62-1	Bad Data EPROM	Bad EPROM data
63	Processor Tray Open	Main processor door has been opened and closed since last game played
65-0	Bad EEPROM Device	Processor could not successfully read from or write to chip
65-1	Bad EEPROM Data	Data is invalid or corrupted
65-2	Game Type Mismatch	Game data om CMOS RAM does not match game data in EEPROM
66	Game EPROM Changed	Machine senses the game EPROM has been changed
67	Data EPROM Changed	Machine senses the data EPROM has been changed
68	Non-Compatible Data EPROM	Data EPROM is not a standard file
99-1	Bill Validator	Stacker jam
99-2	Bill Validator	Cash box removed
99-4	Bill Validator	Cash box full
99-5	Bill Validator	Hardware error
99-6	Bill Validator	Reverse bill detected

Hopper is Full and Coins Go Down a Chute to Bottom of Machine

Slot machines that accept coins were designed this way because when used constantly on the casino floor, hoppers could quickly fill. There is a coin level probe on side of the hopper that looks like a brass screw sticking inward toward the hopper bowl. This probe detects when coins/tokens are at a selected level, and will cause the subsequent coins/tokens played to go down a chute to the bottom of the slot machine.

Slot Machine Expected Value Formula

Provided your slot machine sets on a regular casino slot machine stand with holes in the top and the holes are aligned with the slot machine, those coins which bypassed the hopper will go down the chute, through the hole in the bottom of the machine, through the hole in the top of the stand, and into the open area in the stand cabinet. As casinos have done for years, place a small plastic tub in the slot machine stand cabinet to collect these excess coins.

Retrieving Currency from the Cash Box

Though not all slot machines are equipped to accept currency in order to comply with certain laws but if your slot machine is equipped with a bill acceptor, bill transport and cash box, the bills in the cash box can easily be retrieved.

Slot Machine Expected Value Calculation

• Open the slot machine main door. The cash box door is located just under the yellow chute for the bill acceptor. Ensure the cash box door is fully open.
• On the right side of the cash box toward the top is a release level. Push release lever down and pull the cash box straight out toward you. If the cash box seems difficult or impossible to pull out, make sure you have pushed the release lever down.

• Hold the cash box in both hands and turn it upside down. Notice on the bottom of the cash box is a door which has two small finger sized holes on one side. Normally the door is held closed by a small piece of electrical tape so the bottom cash box door doesn’t come open while removing it from the cash box chassis of the slot machine.
• While holding the cash box with the bottom door up toward you, open the door and you will see where the bills are stored. The large spring expands as more and more bills are added to the cash box. Remove the bills by pulling them straight out.
• Close the bottom door of the cash box and re-secure the door using the same small piece of electrical tape. Turn the cash box around to the original position when you removed it from the slot machine.
• Align the flat top of the cash box with the flat surface at the top of the cash box chassis from which you removed it. Slide it firmly into place. Now close the cash box door and the main slot machine door and you are ready to use it for gaming.

All the content, graphics and videos in this post have been gathered by research for you from various online sources and hope this helps you as a guide to repair your slot machines. Note that many guide books and manuals too are there for you to buy from online stores which are handy to know as how to repair your slot machines. Just stay tuned at realslotmachinesforsale and know many more interesting information about slot machines.