Issue 307
July 31 - August 4, 2006
Volume 6
page 3

Does the RNG Control Free Spins Too?
By John Robison

My wife and I like to play the penny and nickel slots. On a game such as "Twilight Zone", when you get the bonus free spin games, does the RNG apply on those "free spins" too? Or does something else come into play?

Thank you,

Dear Bob,

The RNG is used to determine the results of the free spins too. The only difference between a free spin and regular spin is that you didn't need to pay for the free spin.

Best of luck in and out of the casinos,

Class II question....

I was thinking the other day....

If Class II Slots (Electronic Bingo) are truly "BINGO GAMES" added by electronic means (almost the definition in every state)....

Are "BINGO GAMES" a distribution of winnings to one person "per BINGO-card"/game...(Isn't that how BINGO is played)?

And if "distribution of winnings" are to one person per BINGO game" is true...

Why would anyone play more (a quarter a line) than what it takes to "win a BINGO game"? Especially if there is no distinction between a .25 or a .50 "buy-a-line".

How does the central computer tell the one machine that it has won? And how does it separate or "distribute" the winnings equally to multiple players? Then wouldn't it be possible that a person playing a $5.00 slot and a person playing a .05 cent slot both have the "equal" chance to win the same "BINGO Game" or are there different "games" for different denominations?

How does the central computer "spread the winnings" to all who have "winning cards?" Is it then random if I did win the "BINGO GAME" how much the return or pay out would be? How does the machine keep its percentage of paid out true? The slot would then have to communicate back to the server that it needs to pay out or, is the main computer the "true" slot machine paying out a percentage doing that equally?

Thanks for clearing this up for me...

Dear bryon1,

The central computer in Class II gaming draws a set of numbers and sends them down to the slot machines. The slot them covers the numbers on its bingo card and if the pattern matches one of the patterns corresponding to a winning combination, the reels will stop on that combination. The central computer does not tell machines that they have won.

The actual paybacks on machines approach their long-term paybacks for the same reason that the same thing happens on Class III devices. Each number is equally likely to be drawn, each pattern will be covered with a frequency very close to that predicted by the probability of covering it, therefore each machine will pay back a percentage very close to its long-term payback percentage. Random Sampling with Replacement governs Class II devices too.

I don't know whether all denominations participate in the same drawing or if there are separate drawings for the different denomination. I would think that there is just the one drawing. Perhaps someone in the industry with experience with Class II devices can send me a definitive answer, which I would be happy to publish in a future column.

Best of luck in and out of the casinos,

Hi, John,

You may have already gotten a slew of email about this, but there is an error in your payout calculations from your June 19th column. It is as follows:

You write: "Let's say a 91% machine has been out on the slot floor for a year. This is a 3-coin dollar machine and has had 1,000,000 spins played on it, so it has had $3,000,000 played through it. Let's also say it has paid back $2,700,000. It's actual payback percentage is spot on the long-term, 91%."

But the actual payback percentage here is 90%, not 91%. This becomes important when contrasted with the new payback percentage you provide after a $3 spin hits a $10,000 payout (new payout = $2,710,000/$3,000,003 = approx. 90.3%). Against the incorrect number the payout actually appears to decline with the win.



As you probably know by now, $2,730,000 would be 91%.

But thanks for the great columns you write.

Dear Steven, et al.,

Thanks to you and all the others who pointed out my error. I changed the payback percentage when I ran the calculations to make the numbers easier to follow and neglected to change the payback percentage in the text. I have corrected the text of the article.

The point of the example, if I may repeat it, is to show that after machines have had a reasonable amount of play, jackpots have very little effect on the machines' actual paybacks. It's like a drop of food coloring in a bathtub.

Best of luck in and out of the casinos,

Hi, John,

Recently the Cherokee Indian Tribe made a deal with the State of Oklahoma so that they may have Class III Slots and Video Poker along with their Class II Bingo Slots.

When they moved the Video Poker IGT slant tops and uprights in, they over did the quantity of machines versus the amount of people who were use to playing VP. They've moved them around, added some multi-play, Super Times Play, and Spin-Poker, along with slant top slots. This has decreased the number of original IGT slant top machines.

Where do the old machines go? Do they just lease them, purchase them and junk them out or what? They were not over a year old and in excellent condition. At about 10K per machine, that's quite a loss if they purchased them. I was just wondering if you had some information on an unwanted Slot/VP homeless shelter.


Dear Jim,

Any of those scenarios (lease or purchase, resell or junk) is possible.

Best of luck in and out of the casinos,

Hi, John,

If you were going to open a casino, what type of a casino would you open up?


Dear Tom,

An immensely profitable one.

Best of luck in and out of the casinos,

Send your slot and video poker questions to John Robison, Slot Expert, at Because of the volume of mail I receive, I regret that I can't send a reply to every question. Also be advised that it may take several months for your question to appear in my column.


About the Author

John Robison is an expert on slot machines and how to play them. John is a video poker columnist and writes for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer with Frank Scoblete, which is broadcast from Memphis on WMC 790AM Saturday morning from 9:30 to noon Central Standard Time. John is on the show from 10:30 to 11:00. You can listen to archives of the show on the web anytime.

The Slot Expert's Guide to Playing Slots

Learn the secrets of today's new slots--how they work, what they pay, and how to play 'em! The Slot Expert's Guide to Playing Slots is packed with powerful information on choosing a machine, payout percentages, slot myths, the value of systems, taxes on jackpots, tipping, using slot clubs, and more. Included are strategies for Double Diamond, Wild & Loose, Wild Cherry, Red White & Blue, Sizzling 7s, Blazing 7s, Wheel of Gold, Ripley's Believe It or Not, Price Is Right, Scrabble, Megabucks, Wheel of Fortune, Millionaire Sevens, and almost any machine on the casino floor. Use the Slot Expert's tips to last longer and have more fun playing today's most popular slot machines.


Friday Night Fever Weekly Slot Tournament
Sam's Town Tunica, Robinsonville, MS
Every Friday night
Registration: $20.00
Call 800-456-0711 for more information

King's Ransom Blackjack Tournament
Boulder Station, Las Vegas, NV
Every Saturday
Registration: $25.00
Call 702-432-7777 for more information

Tell us what you think about our newsletter.
Copyright � 2000-2005 Casino City. All rights reserved
Casino City is a trademark of Please read our Disclaimer of Warranty