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Inside Slot Tech MagazineInside Slot Tech MagazineSeptember 2004September 2004September 2004September 2004September 2004

Slot Tech Magazine is anOfficial Publication of

TechFest 10 is Coming!TechFest 10 is Coming!TechFest 10 is Coming!TechFest 10 is Coming!TechFest 10 is Coming!Las Vegas, NevadaLas Vegas, NevadaLas Vegas, NevadaLas Vegas, NevadaLas Vegas, NevadaNovember 16-18 2004November 16-18 2004November 16-18 2004November 16-18 2004November 16-18 2004

Page 2 - Editorial

Page 4 - Williams Bill Acceptor Interface Board

0 - Cold Cathode Fluoride Lighting

Page 12 - Opto Devices

Page 18 - High Speed Diodes

Page 22 - Atronic Systems’ ‘Progressive’ Products at G2E

Page 25 - Unicum Introduces Adventures in Ukraine

Page 26 - Bally Taps Colwell as Director

Page 26 - Russian Regional Operators Conference

Page 28 - Better Connected

Page 32 - Darlington Transistors

Page 36 - Subscriptions and Back Issues

Slot Tech Editorial

Randy Fromm's

Slot Tech Magazine

EditorRandy Fromm

Technical Writers

Martin DempseyKevin Noble

Herschel W. PeelerScott Reynolds

John Wilson

Advertising ManagerDennis Sable

Slot Tech Magazine ispublished monthly bySlot Tech Magazine1944 Falmouth Dr.El Cajon, CA 92020-2827tel.619.593.6131fax.619.593.6132e-mail

[email protected] the website at

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Copyright 2004 under the Uni-versal Copyright Convention. Allrights reserved.

Slot Tech Magazine September 2004

Randy Fromm - Publisher

Randy Fromm

Summertime, and the liv-ing is easy. I actually had

the entire month of Augustoff (well, no travel or techschools, at least). There’s alot going on in the industrybut most of it is behind-the-scenes as the industry pre-pares for the Global GamingExpo in October. I can hint atsome interesting new ticketprinters but the details willhave to wait until next month.You’ll also have to wait untilOctober for the next install-ment of John Wilson’s “TheBig, The Bad And The Bonus”

as John is taking a break thismonth after contending withsome serious flooding in hishometown of Peterborough,Ontario. That’s in Canada,for those who are a little shortin the geography department.Canada is the really big,mostly cold and/or wet placebetween the USA and theNorth Pole. John’s okay(thanks for asking) but hereports that he has spent agreat deal of time assistinghis neighbors and others inthe community and, as such,was unable to meet the dead-line for this issue. Kevin Nobleis on summer hiatus as well,which brings us to (trumpetsblast) . . .

Herschel Peeler and his lat-est test fixture, a really simpleunit for testing Williams’ BillAcceptor Interface Board.Herschel is an electronicspurist who just hates to throwanything away if it can betested and repaired quicklyand inexpensively. His littletest fixtures allow him (andnow you) to do just that. Theillustrated guide begins onpage four. Also from Herschelis another Slot Tech Maga-zine look at optoelectronics,beginning on page 12.

I wouldn’t normally use thiseditorial page to call atten-tion to an advertisement butyou should take a look at the3M Touch Systems advertise-ment on page three. It’s lessof an ad and more of an invi-tation to attend the G2E showfor free as their guest. All slottechs are invited to stop bythe 3M Touch Systems(MicroTouch) booth and jointhe 3M Engineers who will be

providing technical demon-strations on:

• Replacing MicroTouchTMTouch Screens• Using MicroTouchTM Driv-ers and Diagnostic Tools• Fine-tuning Touch SystemDiagnosis• Touch Systems TechnicalReviews• Technical Support Ques-tions

There is a limited number offree show passes available.At TechFest, 3M Touch is fa-mous for their giveaway items.At G2E, they continue thetradition with the promise ofa technical giveaway for allparticipants. Hmmmm. Iwonder what they have for usthis time. Now, where did Iput that pair of electronic diceI received from them atTechFest 7 in Atlantic City?Anyway, you can meet theengineers at the 3M Booth,#4569.

There’s more inside as well.Enjoy what's left of your sum-mer.

See you at the casino


Slot Tech Feature Article

How can such a littleboard cause suchproblems? This board

is an interface between thegame (in older Williams 360,550, 40S era games) and theWBA bill acceptor. It isn’t thatthere is anything tricky aboutthe board. There just isn’troom to troubleshoot theboard while it is in the game.It is much easier to swap the

board out and test, trouble-shoot and repair the board atthe bench. The board is notvery expensive, but repairsare even cheaper. The boardonly has two ICs, four tran-sistors and a few capacitorsand resistors. All of the partsare easy to obtain and are notproprietary. The board con-verts the Open Collector sig-nals coming from the BillAcceptor to the RS-232 levelsignals going to the game.

The board is powered fromthe +12 Volt line coming fromthe game. This same +12 Voltsis passed on through theboard to power the Bill Ac-ceptor. This +12 Volts isdropped down to +5 Volts byU2, an LM78L05ACZ and this

+5 Volts powers U1, anHIN232CP / MAX232CP /ICL232CP (all plug-in replace-ments).

The HIN232CP has a built inoscillator that generates +Vand -V for the RS-232 Inter-face. It also takes TTL signals(+5V and ground) and con-verts them to +V and -V forthe RS-232 signals. This is atwo-channel device. Only onechannel is used.

Q1 and Q2 take the TTL sig-

Williams Bill Acceptor Interface BoardA-004307-02, 5779-004308-02 By Herschel Peeler


nal “R1 Out” from theHIN232CP and convert it toan Open Collector driver go-ing to the Bill Acceptor. Q3and Q4 take the Open Collec-tor info coming from the BillAcceptor and convert it toTTL going into the HIN232CP.The HIN232CP takes the TTLsignals and converts them toRS-232 the Williams gameexpects.

The two connectors on theboard are pin-to-pin on pins1, 3, 4, 7, 13 and 14. Pins 1and 3 are +12 Volts. Pins 4and 7 are ground.

Troubleshooting in the Game

Pins 1 and 3 on both connec-tors should be +12 Volts, withpins 4 and 7 being the ground.Pin 13 on each connectorshould be the same voltage.Pin 14 on each connectorshould be the same voltage.Pins 8 and 9 are the signalsand the voltage here will de-pend on what the BA is doing.

U2 should have +12 Volts onpin 3 and +5 Volts on pin 1.

Pin 2 should be ground.

U1 should have +5 Volts onpin 16 (this comes from U2).Pin 15 should be ground. Pin2 should be about +9 Voltsand pin 6 should be about -9Volts. These are voltages gen-erated by the HIN232CP so ifthey are bad, the HIN232CPis likely to be bad. The othervoltages around U1 are notpredictable in the game. Weneed a test fixture to applypredictable signals to theseother lines of U1 so we cancheck them.

Test Fixture

Many games have a boardwith a similar function to theA-004307-02. With this inmind we made the design ofthe test fixture general innature and envisioned sets ofcables to go with differentboards.

We need to take switch in-puts (open collector) and feedthem to the TTL side of theboard. We will monitor theRS-232 side with LEDs. Use

these same RS-232 signals tofeed back into the board be-ing tested as the returningRS-232 signals. Coming backout of the board, we shouldget our signals converted backto TTL signals and finally backto the Open Collector signals.

We could drive our signalsdirectly with switches but wewant to emulate the samedrive capability as we wouldhave from the game. A switchthat can pull amps of currentto ground might hide a prob-lem on the board.

If we power our test fixturefrom a power supply with acurrent monitor on it, we cancheck for excessive currentdrain on the power line froma shorted capacitor or IC, sowe will use a bench powersupply.

Total cost if we had to go outand buy all the parts wouldprobably around five dollars,not counting the case. Inkeeping with our general de-sires, we have designed thetest fixture around parts we


already have in stock forboard repair. If you forego thebox, the only added expenseis a couple of dollars for theboard to build it on (RadioShack 276-168 with lots ofroom to spare).

Using the Test Fixture

1.Set the power supply to 12Volts. set Current Limit to100 mA. Turn the power sup-ply off.2.Connect the test fixture tothe board to be tested.3.Turn the test fixture switchoff (High out to the board).4.Connect the test fixture tothe power supply.5.Turn the power supply on.All the red LEDs should light.6.Turn the test fixture switchon (Low out to the board).The green LED should be on.The red LED on the BA sideshould be off.

If all this works, the board isgood.

How the Test Fixture Works

We have one switch that rep-resents the data coming fromthe Bill Acceptor TransmitData Line. When this switchis on, we apply a high (open)to the Interface board. Whenthe switch is off, we apply alow to the Interface board.The Interface board convertsthis high and low to an RS-232 signal of +7 Volts and -7Volts that would go to thegame’s RS-232 port.

In the test fixture, we haveturned this RS-232 outputback around and sent it into

the RS-232 input side (like aloopback connector). We havetwo LEDs monitoring this RS-232 line. The red LED shouldlight when the RS-232 out-put is high (+7 V). The greenLED should light if the RS-232 output is Low (-7 V).

The board takes this “turnedaround RS-232 signal” andconverts it to a TTL level.Circuitry on the board con-verts it to the Open Collectorsignal for which the BA isdesigned. An LED on the BAside indicates that the signalfrom the switch went bothways through the BA Inter-face board and it came outgood.

Troubleshooting the boardon the bench

The first six checks, and thevery last, should always bethe same. The others, start-ing from the signal comingfrom the switch and workingthrough the board you shouldfind these voltages.

- Herschel [email protected]

The Test Fixture is built on a Radio Shack 276-168with lots of room to spare.

Visit the Herschel PeelerCollection at the Slot TechMagazine FTP server.

Point your ftp client to:slot-tech-ftp.serveftp.comusername = Slot Techpassword = kxkvi8


Slot Tech New Product

Coin Mechanisms Inc.announces therelease of its Cold

Cathode Fluoride (CCFL)Lighting range of products.The CCFL range of lightingproducts offers casinos andslot machine manufacturersa viable alternative tofluorescent lights commonto most slot machines. Themany benefits of using theCCFL include:

· More energy efficientthan comparablefluorescent tubes –uses approximately70% less current,reducing the load onthe machine’s powersupply.

· Burns cooler thanfluorescent lampsreducing therequirement forinternal fans. Anadditional benefit isthat it reduces theload on airconditioning within acasino.

· Long life cycle –20,000 + hoursversus 2,000 hoursfor standardfluorescent lights.

· Power inverter isavailable for 24 voltDC or 12 volt DC,eliminating the needfor high voltageelectricity coming intothe door unit.

· One size fits allapplications – bellypanel, top box anduniversal toppers.

· Requires less depth,creating more usablespace inside themachine for otheritems.

· Lower cost thancomparable standardfluorescent fixtureswith electronicballasts and starters.

· UL and CE approved.

The CCFL comes as a setthat includes the coldcathode lamp, a highlydurable frosted holder/diffuser and the requiredinverter. The 12 volt versionis also available with anoptional 120 volt ACadaptor. The CCFLprovides a bright whiteillumination that dramaticallyenhances the effect createdby machine graphics.

For more information, visitwww.coinmech.com.

Cold Cathode Fluoride Lightingby Coin Mechanisms Inc.



By Herschel Peeler

opto- pref.

From the Greek "optos"meaning eye; vision: optom-etry, opto-electronics

LED

A light emitting diode is justwhat the name implies, a di-ode that emits light. To somedegree, all semiconductor di-odes emit light when they areforward biased. A silicon di-

ode emits a small amount ofinfrared light any time it isconducting. When electronsand holes combine in the areaof the junction, energy is re-leased in the spectrum weperceive as heat; it is infraredradiation. How much is re-leased and the frequency(color) of the radiation is de-pendent on the chemistry ofthe semiconductor.

Silicon is not the only ele-ment used in an LED. Vari-ous "dopants" are used aswell. These dopants are smallamounts of additional ele-ments that are added to thesilicon during the manufac-turing process. Gallium andarsenic are used to make "gal-

lium-arsenide" LEDs. Othermaterials include indium,aluminum phosphides andnitrides. With each one, weget a different color and in-tensity of light. With recentdevelopments in LED tech-nology, we can cover the wholerange from infrared to ultra-violet. A white LED is actuallya blue LED with a phosphorcoating. When the blue ra-diation hits the phosphor, itmakes the phosphor glowwhite.

Phototransistor

All diodes and transistors re-act to light to some degree.When electromagnetic radia-tion hits the junction region,it causes minority currentcarriers in the diode, makingthe diode conduct slightly. Tomake a phototransistor moresensitive to light, all we hadto do was redesign the physi-cal makeup so light can get toa photo diode between thebase and collector of a tran-sistor. The light hits the di-ode and starts the diode con-

aluminium gallium arsenide (AlGaAs) - red and infraredgallium arsenide/phosphide (GaAsP) - red, orange and yellowgallium nitride (GaN) - greengallium phosphide (GaP) - greenzinc selenide (ZnSe) - blueindium gallium nitride (InGaN) - bluesilicon carbide (SiC) - bluediamond (C) - ultraviolet

LEDs emit a wide range of col-ors. The secret is in the"dopants" that change thewavelength of the emitted light.

LED Range of Colors


ducting, which, in turn, en-ergizes the transistor.

Optocouplers, Optoisolators, Photocouplers(Call Them What You Will)

If we put an LED and aphototransistor in the samepackage, we have a devicethat can transfer a signal fromone circuit to another with noelectrical connection betweenthe two circuits. The inputcurrent makes the LED shine.The light turns on the tran-sistor and we have an outputsignal. The light makes theconnection between the twocircuits.

The input side may be asimple LED for a "DC Input"as shown in the illustration(right) or two LEDs connectedin opposite directions for op-erating as an "AC Input" (be-low).

The output device may be asimple phototransistor for a"DC Output" or aphotosensistive Darlington,SCR, triac, FET, or even anelaborate circuit like aSchmitt Trigger or a logic com-patible output.

Most of them have fairly lowoutput current levels, butsome are made to drive a lightload directly (up to about 100mA).

Usually the LED and the

phototransistor sit on onesurface and a reflective domeover the two bounces the lightfrom the LED over to thephototransistor.

Optointerruptors

If we rearrange the LED andphototransistor opposite one

another with a gapbetween them, wecan detect the pres-ence of an objectpassing between theLED and the

phototransistor. These are inpopular use in various as-semblies also.

Looking at some real worlddevices

DC to DC

Starting with the simpler de-vices, these are the mostpopular. These are used to

couple a DC level circuit toanother DC level circuit. Inthe gaming industry we findthese in I/O circuits. As aninput circuit, the optoisolatorprevents electrostatic zapsfrom the player panels fromsurging over to the MPU'ssensitive circuits. An electro-static zap from the playerpanel may cause a surge inthe LED side of theoptoisolator but will not carrythrough to the phototransistorso we protect our inputs.

As an output device, the gamesees only the very predictableload of the LED. Thephototransistor side can con-nect to noisy, unregulated,higher voltage lines. Noise in

the output circuit cannot feedback through theoptoisolator, so the MPU isprotected.

We also find them in switch-ing regulators. We monitorthe output voltage level withthe LED side (on the second-ary side of the transformer)and feed it back to the regu-lating side on the primary.The transformer has isolatedthe two circuits and we haveto keep these two circuitsseparate or things will catchfire. The optocoupler couplesthe signals, keeping theground references unique.

On the input, we have thesame characteristics wewould find on an LED. Wecan expect to find a 1.2 to 1.6Volt level when forward bi-ased. A digital multimeter

should find what looks like adiode.

On the output side, we shouldfind what looks like the emit-ter-collector circuit of a tran-sistor. If we hook a digitalmultimeter across it, thereshould be a very high resis-tance when the LED is noton. As we turn the LED on, weshould see a lowering of theresistance between the emit-ter and collector. Currentshould flow into the emitterLead and out the collectorlead.

What makes one device dif-ferent from another?

One important characteristicis a thing called "currenttransfer ratio" or CTR. As thename suggests, this is theratio of input current (throughthe LED) to output current(through the phototransistor).Typically this is a valuearound 10% to 100% on sim-pler devices.

Maximum output voltage isanother consideration. Whatis the maximum voltage the

We find optoisolators in switching regulators. We monitor theoutput voltage level with the LED side (on the secondary side of thetransformer) and feed it back to the regulating side on the primary.


output transistor can with-stand when the transistor isoff?

Maximum output current isanother consideration. Whatis the maximum current wecan pass through the outputtransistor?

Maximum output voltage atsaturation is something toconsider. When the transis-tor is fully turned on (knownas "saturation") what is themaximum voltage we will havebetween emitter and collec-tor? What current are we talk-ing about? These consider-ations are essentially thesame we would ask in speci-fying a transistor.

DC to Darlington

If we add a second transistor(in Darlington configuration)to the output transistor, wemake the device more sensi-tive to light. Our CTR caneasily exceed 100%.

DC to AC (The Solid State Relay)

Yes, we can make a photo-sensitive triac and have theability to control an AC load

(on an isolated line) from aDC driving source. These maybe low output current devices,designed to drive a high cur-rent triac or we can incorpo-rate the high current triac inthe same case and call it aSolid State Relay (SSR).

AC to DC

If we use two LEDs on theinput side of our optoisolator,we can monitor an AC signal.As the positive half of the ACcycle comes through, one ofthe LEDs is turned on. As thenegative side of the signalcomes through, the other LEDturns on. From a 60 Hz ACline, we get 120 Hz pulses outthe output.

DC to Logic

Other devices are simply de-signed for data communica-tion. We see these on RS-232and other serial ports. Wemay use them for both theinput and output side of ourcircuits. If we are driving along line (hundreds of feet)there is a possibility of pick-ing up noise in our line. Morethan just screwing up ourcommunications, this noiseon the line may be of a highenough voltage and currentthat it can cause damage tothe I/O circuits themselves.Opto devices to the rescue!The DC to DC devices workokay at low speeds, but LEDstend to turn off slowly andspeed is limited to a few thou-sand (or even hundred) Baud.High-speed devices have beendesigned with diodes thatturn off quicker and outputsthat are Schmitt Trigger togive a clean square wave, oreven logic level compatibleoutputs.

- Herschel [email protected]

A Darlington transis-tor configuration isused to boost the CTR.

Inside the Solid-State Relay


Dear Randy,

I am a graduate of your school(about eight years ago). I havebeen coming across more andmore of the “fast-switching”diodes in monitors as well asgeneral repair. I have beentrying to order the same partnumber when possible but thiscreates a lot of downtime wait-ing for the part to come in. Iwould like to stock several dif-ferent types of these diodesthat I would be able to substi-tute for a large portion of theones I come across, similar toregular diodes where I findthat 1N4007 and 1N5404cover most applications. Canyou recommend a few that Ican stock to substitute for the“fast-switching” applications?Any help would be appreci-ated.

Mark

That’s a good question. Al-though not a super commonfailure, it’s nice to know aboutthese speedy little guys.Here’s the deal:

Most of us are familiar withthe common, general-pur-pose replacement diodesMark mentioned. The 1N4000series is probably the mostcommonly used diode in theworld. These 1-amp diodesrange in voltage rating from50 to 1000 PRV. Since youcan always replace a diodewith one of a higher voltagerating, it makes sense to stockthe 1N4007 since it is thehighest rated one available.The cost of the 1N4007 (1000PRV) is not significantlyhigher than the 1N4001,which is just 50 PRV.

Likewise, the 1N5404 Markmentioned is a 3 amp, 400-

volt diode and also a goodchoice as a general replace-ment diode. It’s suitable as areplacement diode for justabout any input bridge recti-fier for just about any moni-tor. Many monitors use 2 ampdiodes in this application buta diode of a higher currentrating can always be used asa replacement. The 1N5404’s400 volt rating is plenty highenough for the 120 VAC powerused in the USA or the 240VAC used in most of the restof the world. Four discrete1N5404 diodes also can beconnected together to form abridge rectifier if that con-figuration is required.

With just these two diodes,you can replace just aboutanything you come across,just by following the twin rulesof using a replacement diodeof the same or higher voltage,

NTE # Crosses for: In These Monitors:NTE552 - 1N4937 FF1004 Kortek/KristelNTE558 - BA159 KortekNTE572 - FR607 TF604 TF606 TF607 CeronixNTE575 - HER108 UF4005 Kortek/KristelNTE576 - HER204 HER205 UF5404 Ceronix/Kortek/KristelNTE577 - RG4C TF307 Ceronix/KortekNTE580 - FR205 MR856 RG4A RGP15J Ceronix/Kortek/KristelNTE588 - EGP20C Kortek

Figure 1


By Randy Fromm

Slot Tech Magazine

the same or higher current,or both.

However, there is anotherimportant considerationwhen selecting a replacementdiode: Speed. The general-purpose rectifiers mentionedabove are really designed towork at 60hz. They may beused for a myriad of otherfunctions such as clamping,damping and steering buttheir raison d’etre is rectifica-tion; turning alternating cur-rent into direct current. Assuch, they are low frequency(read S-L-O-W) devices. Theycannot rapidly switch fromforward conduction to reverseblocking. Attempts to usethese devices in high-speedcircuits often results in inef-ficient circuit operation, com-ponent overheating and, ulti-mately, destruction of thecomponent itself as well asother circuit components.

Where Do We Need High-Speed Diodes?

There are a couple of placeswhere we have to use special,high-speed (also known as“fast-recovery” or “fast-switching”) diodes. One is inpower supplies. Old-fash-ioned linear power suppliesare now few and far between.Switching power supplies arethe name of the game in mod-ern electronics. Switchingregulator power supplies op-erate at anywhere from 25kHz to 100 kHz (or higher)and as such, require high-speed output diodes in theirsecondary circuits (the pri-mary side of a switching regu-

lator power supply operatesoff the 50/60 Hz power lineand uses conventional di-odes). Of course, modernmonitors also use switchingpower supplies and amonitor’s SMPS also requiresthe use of high-speed diodesin the secondary outputs.

The other place that high-speed diodes are used in themonitor is in the horizontaloutput circuit. In a standardresolution television, this cir-cuit operates at approxi-mately 15, 750 Hz. As themonitor’s resolution in-creases, so does the horizon-tal deflection circuit’s oper-ating frequency. VGA reso-lution (640X480) is 31.5 kHz.Moving up to 800 X 600 reso-lution (where most video slotsare) we see a horizontal fre-quency of 35 kHz or higher!We need high-speed diodeshere, not only in the primaryside of the horizontal circuitbut as output rectifiers forany flyback derived powersupplies as well.

In order to satisfy Mark’s re-quest, I did some research. Ilooked at the schematics forsome commonly-used moni-tors and cross-referenced thehigh-speed diodes to theircommonly available NTE re-placements. It didn’t surpriseme that the resulting list wasrather short, regardless of thefact that there were dozens ofdifferent parts with part num-bers like FR607, HER205,RG4C, RGP15J, EGP20C andthe like.

Figure 1 shows a list of thesecommonly available replace-

ment diodes and their uses.

Of course, there are timeswhen the original diode can-not be cross-referenced di-rectly to an NTE component.In that case, you may be ableto Google the part numberand look at a datasheet forthe OEM component. You’relooking for the voltage rating(Vceo) and the current rating(Ic) as well as the speed of thecomponent. As long as you’re“equal to or better than” thesespecifications, your substi-tution is likely to functionproperly.

You can also sort of cheat

and look at the function ofthe component instead of thepart number. Compare theschematic of monitor you’reworking on with another onefrom a different manufac-turer. Try to use similar moni-tors in terms of resolutionand CRT size. If, for example,you have a shorted diode inthe diode modulator circuit,look for the same diode in thesame circuit in a differentmonitor and cross-referenceits part number. Function-for-function, they’re likely tobe equivalent, regardless ofpart number differences.

Please note that regardless of


Slot Tech Magazine

careful cross-referencing,some replacements may notfunction properly. This is notuncommon in manufactur-ing where two components,one from each of two manu-facturers, will have identicalspecifications but one willfunction properly and theother will not. It sounds pre-posterous but it’s a fact of lifein electronics. Something todo with the precise amountof magic smoke in each com-ponent, I suspect.

If you’re looking to stock-upon high-speed diodes, layingin a stock of a half-dozeneach of these diodes will go along way toward providingsuitable replacement diodesfor most of your high-speedrequirements. Of course, ifyou can get the OEM compo-nents, you should always doso if for no other reason thanthat they are very likely to bemuch less expensive. Gener-ally speaking, NTE compo-nents will be significantlymore expensive as they areintended to be replacementparts and as such, are notpurchased in bulk. You’repaying for the convenience ofthe quick cross-reference andthe ability to purchase insingle units or small quanti-ties.

For more information aboutNTE replacement compo-nents, visit the website atwww.nteinc.com.

- Slot Tech Magazine


At this year’s G2E Show,Atronic Systems’ mainfocus will be on inno-

vative new “progressive” andmystery jackpot schemes aswell as player bonus func-tionality. Based on the suc-cess of its wide-area progres-sive jackpot module, AtronicSystems will introduce a WideArea Mystery Jackpot sys-tem at this year’s G2E. AtronicMagic WAP links run verysuccessfully in the states ofArizona, California, Michigan,New Mexico and Wisconsinand have recently even con-nected within several statesto create the top-award win-ning America Magic Jackpot.

Contrary to a progressivejackpot that is triggered bythe top winning combinationof the machine, the mysteryjackpot is triggered by coin-in only which means thatplayers can win the jackpotregardless of whether or notthey have got a winning com-bination on their slot ma-chine. Taking the mysteryjackpot philosophy one stepfurther, mystery jackpots arenow also available on widearea links, thus ensuring big-ger or more frequent prizesand pay-outs.

Slot Tech G2E Preview

Atronic Systems’ ‘Progressive’Products at Global Gaming Expo

In addition, Atronic Sys-tems will introduce severalnew features to its successfulrange of jackpot modules atthis year’s G2E show, suchas:

* Jackpot Scheduler This fea-ture allows defining time pe-riods during which a jackpotis active. This means thatcasino operators can define ajackpot running for example,only two hours a day, duringlow gaming periods or duringhappy hours.

* Hit Delimiter Casino op-erators can pre-define a maxi-mum number of hits afterwhich the jackpot is auto-matically suspended. This isa handy feature to give awaya pre-defined quantity ofprizes (e.g. show tickets, holi-days, cars, etc.).

* Minimum Bet MysteryJackpot Atronic Systems isnow introducing a mysteryjackpot that will only be trig-gered if players play a mini-mum defined bet thus entic-ing players to play more inorder to participate in themystery jackpot.

In addition to its jackpotmodule, Atronic Systems will

introduce several new fea-tures to its state-of-the-artCHIP CASH (smart card cash-less) system, such as multi-site and multi-currency op-eration.

Dynamic solutions fromAtronic Systems combine so-phisticated proven softwaremodules with the industry’smost acclaimed hardwareplatforms, Crystal Web(R) forslot operations and GoldenEye(R) for table games. To-gether with the GALAXIS(TM)range of software modules,Atronic Systems offers an all-compassing managementpackage for casino operators,including slot machine andtable games management,player tracking and loyaltyprogrammes, integrated jack-pot management, cashless,cage and credit managementas well as a real-time analy-sis and reporting tool — allthese modules for eithersingle-site or multi-site op-erations!

Through its holding company,Atronic International, AtronicSystems is a member of thefamily-owned and operatedGauselmann Group, which

Monitor Repair and More!Slot Tech Magazine Announces Two-Week Technician School

Slot Tech Upcoming Event

As many of you are aware, Slot Tech Magazine offers atwo-week technician training course called (for lack of

a better term) the Casino School. It’s kind of a "SuperTechFest" where we have time to cover everything frombasic electronics and troubleshooting to component-levelmonitor repair. Throw in a good mix of detailed training oncoin acceptors, bill validators, ticket printers andtouchscreens and you sort of get the idea. Add the "hands-on" training that is impossible at a three-day TechFest andyou have a program can really boost the skills of a beginningto intermediate level slot tech.

Normally, a casino that wants this type of training willreserve a class exclusively for their own technicians. Webring the training right to the casino. The class size is smallfor the two-week class. In fact, it’s limited to just 16 people.But even that number of folks can be tough for a singlecasino to spare for two full weeks.

In order to make this training available to more slot techs,Chip In’s Island Resort in Harris, Michigan has offered tosponsor the program and allow technicians from othercasinos to join them for the two-week class.

So, the program is set and we’re on for Slot Tech Magazine’sCasino School. To reserve your place in the class at ChipIn’s Island Resort and Casino in Harris, Michigan (Septem-ber 13-24) please go to the website at slot-tech.com,download and return the enrollment form along with yourtuition of $1295.00.

As the class size is exceedingly small, reservations for theclass are strictly on a "first-come, first-served" basis. Whenwe receive your tuition, you’re in. Purchase orders arewelcome and will be invoiced but placement is not guaran-teed until tuition is in hand.

For more information and an enrollment form, please visitthe website at slot-tech.com or give us a call at Slot TechMagazine, 619.593.6131.

See you at the Casino School!

Randy Fromm

has sold more than 1.9 mil-lion machines since incep-tion, and is the second larg-est manufacturer of gamingdevices worldwide.

Atronic Systems has officesin Graz, Austria, Monaco andScottsdale, USA and salesoffices in Lima, Peru andBuenos Aires, Argentina.

Atronic Systems (formerlyMIS Group) was created outof a merger between MIS (Mo-naco Informatiques Systemes),a Monegasque gaming soft-ware company, founded in1991, and GRIPS, an Aus-trian company founded in1985 and famous for theirCrystal Web(R) hardware andnetwork solutions. AtronicSystems develops, sells, in-stalls and maintains inte-grated casino managementsystems for both slot and tablegame operations on a world-wide basis. Atronic Systemshas a dedicated and profes-sional team of 200 employeesworldwide, a portfolio of hun-dreds of customers in morethan 50 countries across fivecontinents and is a recog-nized leader of cashless gam-ing solutions.

For more information, visitthe company's website atwww.atronicsystems.com.

CONTACT:Daniela Schmied43 316 [email protected] [email protected]

Slot Tech Press Release(s)

Ukraine will see UnicumAdventures in September

The Ukrainian premierof the latest ofUnicum’s develop-

ments, Unicum Adventuresvideo slot will take place atthe Kiev Entertainment In-dustry trade show on Sep-tember 15-17.

Unicum Adventures slotwas introduced to the pub-lic during the EELEX 2003show in Moscow in Decem-ber 2003, when the projectwas passing the final beta-

testing stage. The machinedevelopment was based onthe operators’ and players’preferences thoroughlystudied by the companyspecialists. That is why theslot is fully adapted to theCIS market necessities.Adventure’s advancedfunctions make it compat-ible with machines of ahigher class. This new plat-form supports rich-graph-ics and 3D effects; the flattouchscreen makes gam-ing process exciting andextremely comfortable fora player. The operationmenu was designed to pro-vide reports in various for-mats. The user-friendly in-terface allows the operatorto trace both the slot ma-chine and the individualgame’s performance.

“Adventures’ launch has agreat importance for thedevelopment of Unicum’sactivities in the Ukrainianmarket,” said GennadySoga, head of the Unicum’sKiev office. “Unicum hasalways been known to theUkrainian operator as aprovider of high-quality andreliable slot machines fromthe world leading suppli-

ers. Adventures is not infe-rior to its foreign competi-tors in quality, but pro-duced in Russia, the pro-duction and shipping costsare lowered. It is definitelyreflected in the price of Ad-ventures and makes theslot a very promising plat-form in CIS and Ukrainianmarkets in particular.”

Unicum Adventures ma-chines will be available inUkraine in two versions:One is a multi-game pack-age with five games: BonusPoker, Golden Devil,Golden Devil-25 line,Golden Magic, One-EyedJoe. The other one , TamTam, is a single-game slot.It comes out in Septemberand will premier at the En-tertainment Industry show.The amusing story and un-usual soundtrack are notthe only advantages of thegame. Unicum’s develop-ment team worked hard ondetailed graphics, dou-bling, multi-denominationand other features whichwill be available for inspec-tion at the Unicum stand(# A48) at the Kiev expo.

Slot Tech Press Release

Slot Tech Magazine September 2004 Page 27


The first Russian regional operators conferencewill take place in Yekaterinburg on September 30

Slot Tech Press Release

Bally Gaming and Systemshas announced that it

has named ChristopherColwell as Director of NationalAccounts and ParticipationSales.

In his new position, Colwellwill oversee the relationshipsand account activity of themajor Bally national casinoaccounts at the corporatelevel. He will also be respon-sible for the development ofpartnerships and agreementson product deployments withthese casino operators. Addi-tionally, Colwell will providefocused sales leadership onparticipation-style slot prod-ucts.

“This is truly an exciting timeto be joining the Bally Gam-ing sales team,” Colwell said.“The product pipeline is fulland our products on the ca-sino floor are performing well.My focus will be on ensuringthe major casino companiesin the country understandthe value the Bally producthas and that its placementwill lead to a more profitablecasino floor. The next severalyears will be extremely fastpaced as Bally enters into anew growth phase with theintegration of SDG and devel-opment of new platforms.Needless to say, I have joineda company whose outlook isvery bright indeed.”

Colwell comes to Bally Gam-ing and Systems after havingworked in various executivemanagement capacities with

The success of the first con-ference held in Moscow in

April determined UnicumGroup of Companies to orga-nize a new event with empha-sis on operating. The partici-pants showed a great interestin further discussion of ur-gent issues. The dynamicgrowth of the Russian regionalgaming market forces localoperators pay bigger atten-tion to the quality and num-ber of offered services andeffectiveness of businessstrategies. Unicum special-ists plan to discuss modern

methods and operation tech-niques with operators fromUral, Siberia and Far Eastregions. Other discussion top-ics will include human re-sources, management andadministration. The confer-ence will be held in discus-sion format where partici-pants will exchange their ex-perience and ask questions.After the event, all guests areinvited to a presentation ofUnicum video slots and aparty devoted to Unicum’snew office in Yekaterinburg.

Harrah’s Entertainment, Inc.Most recently, Colwell wasDirector of Gaming Opera-tions for the Harrah’s Casinoin North Kansas City, Mo.Previously, Colwell had servedas that property’s Directorand Assistant Director ofSlots.

Prior to joining the Harrah’sorganization, Colwell was aLieutenant Commander in theUnited States Navy, servingas the Executive Assistant tothe Auditor General of theNavy. As a Certified NuclearEngineer, Colwell also servedas the Reactor Propulsion Of-ficer aboard the aircraft car-rier U.S.S. Dwight D.Eisenhower. In addition,Colwell also served as an Ord-nance and Gunnery Officer

aboard the naval warship,U.S.S. Antietam.

Additional information onBally Gaming and Systemscan be found atwww.BallyGaming.com.

Bally Taps Colwell as Director

“On behalf of Table Mountain Casino I just wanted to express ourthanks to you and your team. I couldn’t have asked for anything better.”

Brian Rankin - Slot Technical Manager

On-Site Slot Tech TrainingCustomized Classes Available


Slot Tech Product Introduction

Which would you sayare the most com-mon repairs in your

casino? I’ve never done anystatistical analysis but inaddition the common prob-lems with buttons, bill vali-dators, coin mechanisms and,if you still use ‘em, hoppers(the things that move or allowfor the insertion of foreignmatter) I would put “bad con-nections” on my list of “ThingsThat Fail.”

Bad connections happen sofrequently (in all types of elec-tronic systems, not just slots)that I often remove and reseatconnectors without bother-ing to determine what theconnector actually “connects”and whether or not it couldactually have anything to dowith the problem I am work-ing on. The same holds truefor reseating some of the sock-eted integrated circuits suchas the EPROMs. The way Ifigure it, even if it’s not bad, Imay be preventing a futurefailure by assuring that thecontacts are good and clean.

As most experienced techsknow, this technique is oftensuccessful in reviving an oth-erwise dead or malfunction-ing PCB or system. Just theact of pulling it all apart andputting it back together willoften make things work. We

may not know exactlywhat we did to fix it butit’s working and that’sreally our only concern. Thisis sometimes referred to asan “FM” repair. Freakin’Magic.

This type of repair is simpleand doesn’t require much inthe way of troubleshootingskills but wouldn’t it be bet-ter to not have to make thistype of repair at all? What ifthere was a way to preventconnector problems beforethey happen? I have foundthe cure for the connectorplague. Oddly enough, thesolution is right in my ownback yard in San Diego, Cali-fornia.

Preaching the gospel of “pre-ventative maintenance” forconnectors, CAIG Laborato-ries manufactures a productthat is ideally suited to therugged, 24/7 demands of thecasino. It’s called “ProGold”and it’s a chemical treatmentthat is formulated to improveconductivity and providelong-lasting protection ongold, precious metals andtheir base metals. It condi-tions connectors, contacts

BetterConnected

ProGold provides protectionfor connectors

CAIG Laboratories’ president Mark Lohkemper shows offhis company’s electronic maintenance kits.


and other metal surfaces toenhance their conductivityand their ability to efficientlytransmit electrical signals.

“Usually customers or ser-vice people come to us afterthere’s a problem, instead oftreating the potential prob-lem before it starts,” said CAIGpresident Mark Lohkemper.

Stressing the importance oftaking a proactive approachto service, Lohkemper saidthat the best time to takeaction is when the game isnew; ideally at the time thegame is manufactured.

“The problem is that as soonas you remove and replacethe connector a few times,you scratch the gold off,” saidLohkemper. “It’s actuallyworse! When you apply this[connector] a few times, youscratch the gold off. Now youhave bare copper to bare cop-per and copper oxidizes veryquickly. When you fix some-thing by taking the connectoroff and putting it back on,you’re breaking through thatlayer of oxidation.”

“What our product does forany surface, especially thegold, is that it lubricates toreduce insertion resistancewhich helps protect the goldsurface.” said Lohkemper,indicating the value of usingProGold at the OEM level,

Progold can be applied with apremoistened wipe as well asby numerous other methods.

before the connectors areapplied. “If this is a brandnew connector and hasn’tbeen inserted yet, our prod-uct will penetrate the goldplating and molecularly bondto the base metal. It seals outoxygen.”


Conduction through aProGold coated surface takesplace in three ways. First,ProGold can be displaced byelectrical arc, shock wave orsimple mechanical pressureand will redistribute itselfalong the surface when thedisturbance is removed. Sec-ond, a thin insulating film ofProGold can be dispersed byan electrical field. Finally,conduction takes placethrough very thin films ofProGold by means of a quan-tum-mechanical phenom-enon called “tunneling” whereelectrons travel from one sideof a thin film of ProGold to theother without passingthrough. This is the sameeffect that gives the tunneldiode its name. ProGold alsofills the gaps in the contactsurfaces, increasing the sur-face area and current flow.

However, any connector, nomatter how old, can benefitfrom the treatment. If the gold

surface is already broken or ifthe connector is not goldplated (such as older PCBs orconnector pairs with male andfemale pins that are “tinned”copper) ProGold will keep itfrom oxidizing and/or cor-roding.

The product can be applied ina variety of ways. CAIG pack-ages ProGold as bottles ofsolution, aerosol cans, mini-spray cans, pinpoint dropapplicators, porous tip pens,syringe dispensers or pre-moistened wipes. Dependingon the environment, a singleapplication can last from oneto ten years.

This product may be espe-cially interesting to those op-erating near the ocean or oncruise ships. The sea air canbe murder on connectors. Ifyou find yourself making a lotof FM repairs, ProGold maybe just the thing you need tothese intermittent failures.

Other Products

CAIG manufac-tures a variety ofother products.Some are suit-able to our indus-try. Others arenot. They have agood, generalpurpose electri-cal contactcleaner calledDeoxIT. DeoxITdissolves oxidesand sulfides that

form on metal contact sur-faces, removing these sources

of resistance. This restoresthe contact’s integrity andleaves a thin, organic layerthat coats and protects themetals. Special additives pre-vent the dissolved oxides fromre-attaching, keeping themin suspension and allowingthem to be dispersed easilyby the mechanical action ofthe contact.

DeoxIT works with similar ordissimilar metals. Even whena treated connector mateswith an untreated one, DeoxITwill migrate and coat the othersurface. When the connec-tors are separated, DeoxITwill re-coat the exposed metalsurfaces.

CAIG also manufactures acouple of other products thatwe can use on a regular basisin gaming. One is an aerosolglass cleaner called OpticALL.Call it Windex with an atti-tude. It’s a general purpose,anti-static glass cleaner.DeoxIT is a general-purpose

contact cleaner.

Eliminate those pesky static prob-lems on CRTs, glass and carpetswith OpticALL and StaticALL.


Winter days can cause an-noying problems with staticelectricity. While slot ma-chines are specifically hard-ened against ESD hits, it’sbetter if the static electricitycan be neutralized at thesource rather than zappingyour customers every timethey walk up to a machine.

CAIG makes a product calledStaticALL that kills static onfloors (and anything else ittouches, for that matter).When static becomes a prob-lem, simply spray the carpet-ing in the area immediately infront of the game. Lightlyspray a radius of five feet orso. I have no personal experi-ence with this product so Icannot tell you if it works anybetter than a couple of cap-fuls of fabric softener in apistol grip sprayer full of wa-ter when it comes to killingstatic electricity on carpet-ing.

Locating ThermallyIntermittent Failures

Another CAIG product is acomponent chiller calledFreezALL. FreezALL cools cir-cuits down to -54 degrees Cand comes packaged with aprecise one-piece trigger valveand extension tube for con-trolled application. Naturally,this product contains noCFCs/HCFCs.

Here is a repair trick that’sworth its weight in gold. Manygames fail when they get hot.The game will work fine whenit is first turned on but after

warming up, the CPU board(or some other sub-assem-bly) fails. This type of failureis “thermally intermittent”and you can locate the defec-tive component with just twotools: a hair dryer and a canof FreezALL. With the gameturned on, use the hair dryeron the hottest setting to heatthe components on the board.If you’re working on a CPU,start with the socketed ICs:the EPROMs and EEPROM.Practical experience hasshown that heat related CPUfailures are often caused bythe memory devices. Don’t beafraid to get them good andhot. You cannot damage anIC (or any component, for thatmatter) with the heat of anormal hair dryer. When youheat the bad part, the gamewill fail. This will lead you tothe general area of the fail-ure.

To precisely locate the badpart, use the FreezALL. Thenozzle comes with a tube thatallows you to aim the sprayon a single component. Onceyou have induced the failureby heating the componentson the board, carefully spraythe parts one at a time withthe FreezALL. The FreezALLspray will cool the compo-nent instantly. If the defec-tive part works properly whenit’s cold, the game will sud-denly begin to work when it ishit with the cold FreezALLspray. To make absolutelysure that you have isolatedthe bad IC, try heating andfreezing it a few times. Eachtime you heat it with the hair

Isolate thermally intermittent prob-lems with environmentally friendlyFreezALL.

dryer it should fail. Freezingthe IC should cause the com-puter to regain consciousnessor otherwise restore the func-tionality of the circuit.

Of course, freezing the badpart is only a way to locate it.The FreezALL spray does notfix the bad component. Thedefective part must be re-placed. This method worksfor any electronic failure thatis thermally intermittent. Thesuccess rate is 100 percent.

For further information, contact:CAIG Laboratories, Inc.12200 Thatcher CourtPoway, CA 92064-6876E-mail: [email protected]/CAIG-123(800/224-4123)Main Line: 858/486-8388Main Fax: 858/486-8398

Slot Tech Electronics 101

We have discussed acouple of differenttypes of transistors

in past issues of Slot TechMagazine. We have discussedconventional, bipolar transis-tors and we have taken lookat field effect transistors orMOSFETs. Now, it's time tointroduce you to yet anothertype of transistor. It’s calledthe Darlington transistor.

There is really nothing mys-terious about a Darlingtontransistor. It is simply twotransistors, in a single tran-sistor package. In aDarlington transistor, theemitter of the first transistoris connected to the base ofthe second transistor (see fig-ure 1). The two collectors aretied together. This still leavesus with a single device withthree leads coming out of thepackage: the emitter, thebase, and the collector.They’re in the same place asthey are in a standard TO-220 package. That is to say,the leads are in alphabeticalorder from left to right: base,collector, and emitter (see fig-ure 2).

So what is the advantage of aDarlington transistor over aconventional transistor?Think about the specifica-tions for transistors for just amoment. Remember that

transistors are rated by volt-age, current, and anotherparameter known as gain.This is where the Darlingtontransistor has its advantage.

The gain of a transistor is anindication of the transistor’sability to amplify an incom-ing signal. The higher thegain, the less current it takesto drive the transistor. Forexample, a transistor with again factor of 100 will requirejust 1/100 amp of base cur-rent for 1 amp of collectorcurrent.

There are three general cat-egories for gain in transis-tors. There are low gain tran-sistors, there are mediumgain transistors, and thereare high gain transistors. Alow gain transistor is a tran-sistor that has a gain of up toaround 250. A medium gaintransistor might have anygain from 250 to 750. A highgain transistor would behigher than 750. These gainassignments are somewhatarbitrary.

In a Darlington transistor,the gain of the first transistoris multiplied by the gain ofthe second transistor. To il-lustrate, let’s look at an ex-ample. Let’s say that this firsttransistor has a gain of only100. That makes it a low gain

transistor. Let’s say, for thesake of discussion, that thegain of the second transistoris just 20. That’s also a verylow gain transistor. Together,the Darlington transistor hasa gain of 2000. That’s a veryhigh gain transistor.

What do you suppose is theadvantage here? Why do weneed a high gain transistor?Darlington transistors are of-ten used as driver transis-tors. They often are used todrive coils or solenoids. Wemight also use them in slotmachines as lamp drivers. Ina slot machine, a lamp circuit(a lamp matrix, for example)draws a reasonably highamount of current. But re-member that the transistor isdriven by the CPU, the com-puter in the game. Well, thecomputer is very smart, butit’s also very weak. The com-


Darlington Transistors

Figure 1.The Darlington configuration


puter itself cannot put outenough current to drive alamp. Instead, the weak sig-nal from the CPU is used todrive the Darlington transis-tor. Since the Darlingtontransistor has a huge amountof gain, the tiny, weak signalfrom the CPU can be used todrive the high current lampcircuit.

Testing

When you test a Darlingtontransistor, it tests differentlyfrom a conventional, bipolartransistor. When you test theDarlington transistor be-tween base and collector, youto get a normal junction drop.That is to say, with your meterset on the diode test setting,you see a typical forward junc-tion drop voltage of betweenaround .5 volt or .6 volt. Onthe other hand, when youtest between the base and theemitter, you still see a junc-tion drop but it is somewhathigher than the junction dropthat we saw between the baseand collector. As you know,in a normal, bipolar transis-tor, the junction drop read-ing obtained between the baseand collector is normallyabout the same as that be-tween the base and emitter.In this case however, whenyou measure between baseand emitter, the junction dropthat you get is somewhathigher because you are actu-ally measuring between twoPN junctions and they are inseries. When you test theDarlington transistor be-

tween base and emitter, thePN junction of the first tran-sistor is being tested in serieswith the PN junction of thesecond transistor. Therefore,the junction drop reading thatyou get on your meter is some-what higher. For example, ifyou measured .5 volt betweenbase and collector, you mightobtain a reading of .6 be-tween base and emitter.

Yet another interesting read-ing you will get is when youmeasure between the collec-tor and emitter. In a conven-tional, bipolar transistor, youwill normally get an openreading between collector andemitter. You will get the sameopen reading both ways. Thatis to say, with red meter leadon the collector and the blackon the emitter, your meterwill read open. When theleads are reversed and the

black lead is on the collector

and the red lead is on theemitter, you will get the sameopen reading.

Not so with the Darlingtontransistor. When you test theDarlington transistor be-tween collector and emitter,you will get open reading inone direction but you’ll reada junction drop when theleads are reversed. Hmmmm. . . That’s very interesting.What component do we knowthat tests that way? Whatcomponent tests open in onedirection and junction dropwhen the leads are reversed?It’s a diode of course. Builtinto the Darlington transis-tor, between the collector andthe emitter, there is a diode.This diode is a protection di-ode. In a nutshell, any timewe use a transistor to drive acoil of some sort, you will seesome protection diodes used.


Since a common function ofthe Darlington transistor isthat it is used as a coil driver,the diode is built right in tothe Darlington transistor.

But that’s not all. In additionto the diode, there are typi-cally a couple of resistors thatare also built in to theDarlington transistor (see fig-ure 1). These resistors areconnected between the baseand emitter of each of the twotransistors that are in theDarlington transistor. Thepresence of these two resis-tors profoundly affects thetransistor test. Where younormally see a junction dropin one direction and openreading when your meterleads are reversed, the resis-tors allow current to pass evenin the reversed direction. In-

stead of reading open on yourmeter, you will typically getsome sort of voltage drop.

The reading you get dependson a couple of factors. One isthe value of the resistorsthemselves; the other is yourmeter. Different meters passdifferent amounts of currentand voltage through the de-vice under test. While somemeters might read somethinglike 1.8 volts of voltage dropwhen the leads are reversed(actually reading the resis-tors themselves and notthrough the transistors at all)other meters might showsomething like 1.2 V. Thebest way to determine what’snormal, is simply to try test-ing some known goodDarlington transistors withyour meter. Whenever it is

that you’re reading with yourmeter, that is what’s normal.

Specifications for Darlingtontransistors are the same asthose of regular transistors.That is to say, they are ratedby voltage, current, and gain.Substitution is the same aswell. You can always substi-tute the Darlington transis-tor for another Darlingtontransistor as long as the volt-age rating is the same orhigher, the current rating isthe same or higher, and it hassufficient gain. Rememberthese are the rules when sub-stituting any transistor. Volt-age and current can be thesame or higher but you needto try to match the gain. Itdoesn’t have to be exact, itjust has to be close.

Slot Tech Magazine

Darlington transistors comein both polarities (NPN andPNP) and in all the same tran-sistor packages as conven-tional transistors. The mostcommon package that we seein gaming is the TO-220 pack-age.

Darlington Array

Another place we useDarlington transistors ingaming is as a Darlingtontransistor array that looksjust like an integrated cir-cuit. One popular type is theULN2084A.

The ULN2804A is a mono-lithic high-voltage, high-cur-rent Darlington transistor ar-ray, comprising eight NPNDarlington pairs. All units fea-ture high-voltage outputswith common-cathode clampdiodes for switching induc-tive loads. The collector-cur-rent rating of each Darlingtonpair is 500 mA. Outputs andinputs can each be paralleledfor higher current capability.

Applications include relaydrivers, hammer drivers,lamp drivers, display drivers(LED and gas discharge), linedrivers, and logic buffers. TheULN2804A has an approxi-mate 10.5 kilohm series in-put resistor to allow its op-eration directly from CMOSor PMOS, utilizing supplyvoltages of 6 to 15 volts.

- Slot Tech Magazine

Subscriptions & Back IssuesWhy back issues of Slot Tech Magazine areimportant to own . . .

Slot Tech Magazine is strictly technical. As such,the magazine's contents are not time critical. Therepair information and technical data containedin past issues is just as valid today as it was the day it was published.

Additionally, current and future articles more-or-less assume that readers are alreadyfamiliar with what has been covered in past issues. This editorial policy assures that SlotTech Magazine's contributing writers are not limited to "writing down" to the level of anovice technician but are free tocontinue to produce the most com-prehensive technical articles inthe gaming industry.

Randy Fromm'sSlot Tech Magazine ispublished monthly by:Slot Tech Magazine1944 Falmouth Dr.El Cajon, CA 92020-2827tel.619.593.6131fax.619.593.6132e-mail [email protected]

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