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Slot Tech Magazine

EditorRandy Fromm

Technical WritersJames Borg, Jason Czito,Vic Fortenbach, DianaGruber, Henry Kollar, ChuckLentine, Craig Nelson,Kevin Noble, Pat Porath

Slot Tech Magazine is publishedmonthly bySlot Tech Magazine401 W. Lexington #777El Cajon, CA 92022tel.619.838.7111 fax.619.315.0410e-mail [email protected] the website at slot-techs.com

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Copyright 2014 under the UniversalCopyright Convention. All rights re-served.

Slot Tech Magazine

-EditorialPage 4-Boost or Buck?

(Plus “VIPER” Circuit)Page 12-TechFest 29 ReviewPage 16-Quick & Simple Repairs #107Page 20-UNI-750-1 24 Volt SectionPage 22-Subscriptions

Randy Fromm

Publisher-Slot Tech Magazine

Dear Friends of Slot Tech Magazine,

I want to express my gratitude to all whoattended TechFest 29, held mid-May atMystic Lake Casino. The sold-out eventwas a great deal of fun for everyone in-volved, students and instructors alike. Andmake no mistake about it, it is a three-daySCHOOL. Other than ten-minute breaksand an hour off for lunch, it’s balls-to-the-wall classroom instruction from nine am tofive-thirty pm every day. It’s just not pos-sible to cram more instruction in a threeday period.

I have not decided where TechFest 30 willbe held. Geographical choices range fromthe state of Washington to the Midwest toPennsylvania to Biloxi. If you are inter-ested in sponsoring TechFest 30 at yourproperty (and you have meeting space,catering and a hotel) please contact meand we can discuss it.

Enjoy your summer. See you at the casino.

June 2014Slot Tech Magazine

Slot Tech Feature Article

Electronic systemsneed power. That’swhy we have power

supplies! It is not unusualfor a system to require ahalf-dozen differentvoltages or more and, froma manufacturing point-of-view, this presents a bit of aproblem. Starting with thepower supply itself, theunit must produce multipleoutputs. It would not beunusual to see a singlepower supply with outputsof +24 VDC, +12 VDC, +5VDC and +3.3 VDC. Theremight be negative voltageoutputs as well. Minus 12VDC or -5 VDC outputsaren’t uncommon. We evenhave linear voltageregulators that arededicated to the task-the7912 and 7905 haveoutputs of -12 vdc and -5vdc respectively.

In order to produce anddistribute these outputs tothe circuits that requirethem, we need to usemultiple outputtransformers withindividual secondarywindings for each voltage,we need to rectify and filtereach output separately andwe need to distribute theseoutputs (often with multiplewires for each one) through

a wire loom with multiple,high-current connectorsthroughout. Whew! That’san expensive proposition.Copper’s not cheap. Labor’snot cheap (building a wireloom and attachingconnectors is a labor-intensive proposition).Threading the wire loomthroughout the system androuting it in such a waythat it will not becomedamaged by, for example,opening and closing thedoor of the slot machine orremoving and replacingsub-assemblies, is also an“issue.” More than onewiring harness has beenreplaced due to chaffing ofinsulation or even ameltdown of a wire that,due to some fault, has hadway too much current runthrough it.

Enter DC-to-DC conversion

to the rescue. The conceptis a simple one but onlyrecently made possible bymodern electronics. In anutshell, we use one DCpower supply of a singleoutput voltage, run thatone output everywhere inthe system and, if werequire a different voltage,we derive it from that oneoutput. We can lower thevoltage or we can raise thevoltage and we can do it atefficiencies that approach100%! Efficiency is ameasurement of the powerof the output (in Watts)compared to the amount ofpower required as the inputto produce it. Thedifference in power goesout as waste heat,something we’d rather nothave, thank-you-very-little.A 95% efficiency is easilyobtained with today’selectronics, made possible

Boost or Buck?Power Distribution and Voltage Regulation in the Modern World

Introducing the “Boost” regulator

Slot Tech MagazineJune 2014


by a host of new voltageregulation devices, knowncollectively as “boostregulators” and “buckregulators.”

Boost regulators are usedto raise the output voltageover the input voltage (anexample would be the +5VDC power supply that’savailable at a USB port.This +5 VDC can easily beincreased to +12 VDCthrough the use of a simpleboost circuit).

Buck regulators (the REALfocus of this article) do justthe opposite, lowering thevoltage and, as such,assuming a more traditionrole in the scheme ofvoltage regulation such asthe older style of linearvoltage regulatorsmentioned previously. Thelinear voltage regulator canonly lower the outputvoltage over the input,converting the excessvoltage into waste heat.These devices are generallymounted to heatsinks forjust that reason. Althoughreliable, linear regulatorsare highly inefficient,converting energy lossesinto heat.

With all of this in mind,here is a quick look at two,similar circuits that areused in slot machine powersupplies, presented by twoof our industry’s “smarty-pants” technicians,Herschel Peeler and GlennAllen. These names arefamiliar to anyone that hasspent any time at all on the

“Slot Tech Forum,” whichcan be accessed through“slottechforum.com.”

How it WorksHow it WorksHow it WorksHow it WorksHow it Works

Boost regulators use theenergy stored in themagnetic field of aninductor (a coil) to create anadditional source whoseoutput is then connected inseries to source you’retrying to boost. It’s likeputting batteries in seriesin a flashlight. The sourcesadd together to create asingle source of a highervoltage.

The buck regulator really issimple, especially if youknow something about howmodern, switched-modepower supplies operatethrough a scheme knownas “Pulse-WidthModulation” or “PWM.” Wehave been using PWM fordecades now. The concept,first developed for use insatellites where highefficiency is critical andwaste heat is anathema,allows the power supply toproduce exactly the correctoutput voltage(s) withouthaving to resort to the useof wasteful, linear voltageregulation. Itdoes this bycontrollingthe “dutycycle” (theratio betweenthe “on” and“off” times) ofthe switchingtransistor(s)that drive theprimary

winding of the powertransformer. A longer dutycycle allows a largermagnetic field to build upin the transformer,resulting in a higher outputvoltage while shorter dutycycles produce lowervoltages due to a smallermagnetic field.

The buck regulator worksin much the same way(although no transformer isused). The output voltage islower than the inputvoltage, controlled by theduty cycle of the circuit. Forexample, a +12 VDC inputis converted into a +5 VDCoutput by running the dutycycle at 41.666%. The pulsetrain is converted into pureDC by the addition of acapacitor (or two) on theoutput.

DANGER DANGER!DANGER DANGER!DANGER DANGER!DANGER DANGER!DANGER DANGER!

These regulators are notisolated at all! Without atransformer to provideisolation between theprimary and secondarywindings, any sort of short-circuit in the circuitry thatcouples the input to theoutput can have trulydevastating results,

Introducing the “Buck” regulator


creating mass destructionof the regulator itself and/or the load it is powering.In worst-case scenarios(such as when the buckregulator is used in amobile phone charger) thislack of isolation can cause ashock hazard if there issuch a failure and a personuses the phone while it isplugged in to the charger.There have been someanecdotal reports of peoplebeing shocked (in oneChinese report, killed) bydefective chargers.

Editor’s Note:Unknowledgeable newsreporters often speak of thelow-voltage output of thesepower supplies as beingunable to produce suchshocks. I fear that they donot understand therelationship between theAC power line (AKA the“mains” in most of theworld) and Earth groundwhich, as WE know, canseverely shock or evenelectrocute a person (seeSlot Tech Magazine’s May2014 issue for furtherinformation).

Editor’s Note: TheEditor’s Note: TheEditor’s Note: TheEditor’s Note: TheEditor’s Note: Thefiles referenced infiles referenced infiles referenced infiles referenced infiles referenced inthis article arethis article arethis article arethis article arethis article areavailable on theavailable on theavailable on theavailable on theavailable on theSlot Tech Server atSlot Tech Server atSlot Tech Server atSlot Tech Server atSlot Tech Server athttp://bit.ly/http://bit.ly/http://bit.ly/http://bit.ly/http://bit.ly/RipdFiRipdFiRipdFiRipdFiRipdFi

From Herschel PeelerFrom Herschel PeelerFrom Herschel PeelerFrom Herschel PeelerFrom Herschel Peeler

LNK30x SwitchingLNK30x SwitchingLNK30x SwitchingLNK30x SwitchingLNK30x SwitchingRegulatorRegulatorRegulatorRegulatorRegulator

LNK302, LNK304,LNK302, LNK304,LNK302, LNK304,LNK302, LNK304,LNK302, LNK304,LNK305, LNK306LNK305, LNK306LNK305, LNK306LNK305, LNK306LNK305, LNK306

Used often by SETEC intheir power supplies forWMS, Aristocrat andothers, this is a slightlydifferent brother from otherswitching regulators. Itcomes in an 8-pin package,usually with one pin notused. Pinout differsdepending on the package

so pay attention.

Editor’s Note: Referring tothe datasheet, you’ll noticethat this device is referredto as an “Off-LineSwitcher.” This (obviously)has nothing to do with ourcommon expression ofbeing “off-line” as meaningthat we’re not connected(via computer) to a networkor to the Internet. The“line” in this case, refers tothe AC power line (calledthe “mains” in most of therest of the world). An “off-line” device is one that is


connected directly to theAC power, without theisolation that is provided bya transformer.

An internal 66 KHzoscillator runs it all. A 1mH choke, three capacitors(standard values. 100 nF,10 µF at 35 V and 100 µF at16 V) and two diodes(UF4005 and 1N4005 )make up the circuit we seeoften in these powersupplies. The circuit is rightout of the data sheet.

Two resistors set the outputvoltage. A handy Excel fileand schematic associatedwith this text gives you anidea of what the outputvoltage should be. Thevoltage at the Feedback pinshould be 1.65 Volts andwe should see that acrossR3. This sets the currentwe should find through R1and R3. With the 2.05 KOhm, 1% resistor as shownwe get 0.8 mA. Selectingthe value of R1sets theoutput voltage. 13 K Ohmswith 0.8 mA through itadds 10.4 Volts to this 1.6and gives us an output

voltage of 12 Volts. Valueshave been rounded off forsimplicity. You can getmore precise if you wantbut the concept is thesame.

This chip is used as the DCsupply for start-up onswitching regulators. It ispowered from the +V HighDC (+400 V) to supplyvoltage to the mainswitching regulator controlchip until the mainswitcher gets started.

The difference betweenThe difference betweenThe difference betweenThe difference betweenThe difference betweenthe parts?the parts?the parts?the parts?the parts?

LNK30xG – 8-pin SOICLNK30xP – 8-pin DIPLNK30xD – 8-pin SMD, butDIP size

LNK302x – 80 mA out,maximumLNK304x – 170 mA outLNK305x – 280 mA outLNK306x – 360 mA out

Pinout?Pinout?Pinout?Pinout?Pinout?

LNK30xD1 – Bypass (0.1 µF cap tooutput)

2 – Feedback3 – (nc)4 – Drain (+V DC input)5 – Source (output)6 – Source (output)7 – Source (output)8 – Source (output)

LNK0xP or G1 – Source (output)2 – Source (output)3 – Bypass (0.1 µF cap tooutput)4 – Feedback5 – Drain (+V DC input)6 – (nc)7 – Source (output)8 – Source (output)

TroubleshootingTroubleshootingTroubleshootingTroubleshootingTroubleshooting

Bypass should not be lowerthan 4.85 V (under voltagetrigger point) or higherthan 6.3 V (rated Zenerlimit). It should be 5.8 Voltsif all is working well.

Overcurrent in the outputcauses the chip to shutdown. The sensor is builtinto the design of theoutput transistor so it isn’tapparent to us.


5

5

4

4

3

3

2

2

1

1

D D

C C

B B

A A

12V @ 100mA

90 TO 264 vAC

Jumper = open

L2 = short circuit

D7 = short circuit

C5 = open

Viper12 Buck.opj B

VIPer12 Buck nonisolated 12V @ 100mA

STMicroelectronics John S. Lo Giudice

1300 East Woodfield Road, Suite 410Schaumburg, IL 60173

A

1 1Tuesday, April 13, 2004

Title

Size Document Number Rev

Date: Sheet of

0

C647uF50V

R1 1K

R0101/2W

D61N4005

D11N4007

J2

2 pin

12

C24.7uF400V

L0

470uH

D81N4005

Cx.02250V

C40.47

C14.7uF400V

L1

1mH

D5STTH1L06

DZ116V

C31uF50V

U1

VIPer12A

8 67 5 1 234

Dra

in

Dra

inD

rain

Dra

in

So

urc

eS

ou

rce

Fb

Vd

d

J1

2 pin

12

DZ12V

C70.1u630V


Typical input cap on the Drain is a 4.7 µFcap at 400 V.

The voltage at the Feedback pin should be1.65 V.

Minimum DC in should be about 70 V. Soyou should start seeing operationsomewhere around this point as you bringup the AC voltage.

Regulation of the output voltage ismaintained by skipping switching cycles.As the output voltage rises the currentinto the Feedback pin rises. When thisfeedback current increases to a set valuethe next oscillator cycle is skipped,bringing down the output voltage and thusthe feedback current.

From Glenn AllenFrom Glenn AllenFrom Glenn AllenFrom Glenn AllenFrom Glenn Allen

Mr Allen has not written an “article” onthe subject. Rather, he has contributed areplacement sub-module to us. Thanks,Glenn.

BEHOLDBEHOLDBEHOLDBEHOLDBEHOLD

----From e-mail---

Randy.Here's the little circuit to replace theVB400 Voltage regulator on the MK5. I

contacted STMicro application section toget a replacement for the chip and this iswhat they came up with. I have used thison a few units and it has worked great.

Glenn E. AllenEET / Slot Tech. IIIThree Rivers Casino & Hotel5647 Hwy 126, Florence, OR 97439www.threeriverscasino.comPhone: 541-902-6531Fax: 541-997-4802

---end---

MK5 with Viper PCB installed


Slot Tech Event-TechFest 29 Review

“Kicked Off the Rocks!”TechFest 29 was held at

Mystic Lake Casino(near Minneapolis,

Minnesota) May 13-15, 2014.It was a wonderful eventwith the typical mix of goodfood and great presentationsfrom companies like JCM,Transact Technologies, Fu-tureLogic, MEI (now Crane),3M and Ceronix. Also, PacificIllumination’s Harry Iversongave away a free CCFL testerto everyone in attendance.

I (Randy Fromm) presentedon a few subjects, includingcomponent identification andtesting, power supplies andLCD monitors but the unde-

niable stars of TechFestcame to us from Ceronix.Ken Lema and JillianHaynes brought to TechFesta full-on “HANDS-ON” LCDmonitor repair lab FOR 80PEOPLE! YES I AM YELLING!It was amazing and thesephotos cannot do justice tothe energy, spirit and justplain educational value ofwhat Jill and Ken broughtwith them to the event.

Everyone had a chance totear down and rebuild anLCD panel and everyone hada chance to run through anumber of different “power-on” lab stations where they

could work on actual faultsin power supplies, A/Dboards and inverters. It wasa thing of beauty to watchfourscore slot techs, simulta-neously up to their elbows inLCD monitor repair. Thanks,Ceronix. Ken and Jill wereawesome as was each of my

Diego Mejiafor TransactDiego Mejiafor Transact


FutureLogic’sTony Bowe

The Ceronix labarrives!

3M TouchSystem’s PaulHatin teaches

touch technology.

TechFest welcomes KeithMcKinney representing

MEI/Crane

TechFest presenters. Thanks to them andeveryone that attended.

I apologize for the poor quality of the classpicture for TechFest 29. We were all posed,“Rock Star” style on top of the big fake rocksadjacent to the Minehaha Cafe when wewere chased off the rocks by casino security.I’m pretty sure this was as close as I’ve evercome to being eighty-sixed from a casino!-STMSTMSTMSTMSTM


Slot Tech Event

Slot Tech Training at Twin Pine Casino

Just another class picture. If you were at the class, you’d want to see your picture in Slot TechMagazine. Thanks to all my friends at Twin Pine for their hospitality.

Semi-Famous Slot Tech“DarkDank” from the Slot Tech

Forum


Slot Tech Feature Article

Quick & Simple Repairs #107By Pat Porath

Bally Alpha “Touch Screen Com Error”Bally Alpha “Touch Screen Com Error”Bally Alpha “Touch Screen Com Error”Bally Alpha “Touch Screen Com Error”Bally Alpha “Touch Screen Com Error”

Since this particular game had beenupgraded from a Sentinel II to N-Compass in the early morning

hours, I thought I would look for an obvi-ous problem. Sure enough, the problemwas very obvious. Right in front of me thetouch screen communication cable wasunplugged from the brain box. Main gamepower was turned off, the cable was

plugged back into its socket and presto! Itworked perfectly. When touching the“denomination” and “see pays” menu, itworked as it should.

Multimedia Games Not AcceptingMultimedia Games Not AcceptingMultimedia Games Not AcceptingMultimedia Games Not AcceptingMultimedia Games Not AcceptingPromo Cash or TicketsPromo Cash or TicketsPromo Cash or TicketsPromo Cash or TicketsPromo Cash or Tickets

A while back we received a bank of“Tournevent” Multimedia games for newslot tournament games along with a bigsign with four, 50'’ LCD monitors, two oneach side. After a while it was noticedsome games wouldn’t accept promo cashand or tickets when they were taken out oftournament mode and put back in regulargame mode. Rebooting the N-Compasssentinel would sometimes work, if thatdidn’t then RAM clearing the Sentinel


would fix it. The fix wasonly temporary though.After the tournament wasdone a tech would have totest each game to seewhether or not they wouldaccept tickets and promocash. Recently a OS (Oper-ating System) upgrade wascompleted on the bank.When testing the thirdgame down the line, it didnot accept a ticket. Whatthe? Phone calls were madeand we were told one lastSentinel RAM clear wasneeded to cure the prob-lem. I haven’t heard of anyproblems since.

WMS “Blade” LooseWMS “Blade” LooseWMS “Blade” LooseWMS “Blade” LooseWMS “Blade” LoosePower ConnectionPower ConnectionPower ConnectionPower ConnectionPower Connection

I had received a complaintthat a WMS “Blade” gamehad a power problem. Oncein a while, both of the LCDs(upper and lower) would goout and only display “nosignal.” To me, this indi-cates the LCDs have powerbut no graphics (no video/sync signals) are being sentfrom the game. It could be agame main processor boardproblem, bad video card,bad video cable, loose videocable or maybe even one ofthe game power supplieshad gone bad. My firstguess was a loose videocable on either the LCDside or the CPU side. Sinceboth connections weresnug, I opened up the CPUdoor with game power ONto check it out. Thereshould be some small LEDslit up (indicating power isOK) along with spinningCPU fans, showing that

they too have power. Thisboard was totally dead. Iknew I had power in otherplaces because the Oasis N-Compass display was func-tional, the monitors dis-played “no signal” whichmeant they had power too.Before replacing the gamepower supply, I lookedaround the area of the CPUboard. As I looked closer, Inoticed that a power con-nector right next to theboard wasn’t snapped in allthe way. With game powerOFF, the connector waspushed in all the way into

its socket. Now, when turn-ing ON power there wereLEDs lit up all over the CPUboard. The monitors werefunctioning too. The prob-lem was simply a loosepower connection to theCPU board.

Troubleshooting TipsTroubleshooting TipsTroubleshooting TipsTroubleshooting TipsTroubleshooting TipsWhen Upgrading FromWhen Upgrading FromWhen Upgrading FromWhen Upgrading FromWhen Upgrading FromSentinel IIs to N-Com-Sentinel IIs to N-Com-Sentinel IIs to N-Com-Sentinel IIs to N-Com-Sentinel IIs to N-Com-passpasspasspasspass

When “globaling” the firstgame in a bank (enteringthe slot mast identificationnumber, checking COM


settings such as “SAS” and“200ms” for our system)and it does not work, thereare a few things that can bechecked. One way to tell ifthe CAT5 cable has COM tothe Sentinel is if the twolights are lit up on theconnector. If there are notany lights, there isn’t anycommunication. I recentlyhad a bank of games wherethe first and second gamesdidn’t have any COM. Justguessing, I thought it was aproblem with the computerswitch (the box that has abunch of CAT5 cablesplugged into it). On thefiber optic connections,it was dead; there wereno lights at all. I no-ticed that one of theconnections wasn’tplugged in all the way.After I plugged it in,still no COM so Iswapped connections.They were unpluggedand swapped left forright and vice versa.Right away, the com-munication LED lit up.When I went back tothe first game to “glo-bal” it, COM estab-lished very quickly so Iwent to the next threegames in the bankwhich were workingproperly as well. In anutshell, the computerswitch wasn’t commu-nicating with the Senti-nels, which weren’tcommunicating withthe games. Now thatthe switch was workingproperly, everythingelse worked on downthe line.

I had a game for which Ireceived a complaint thatthe accounting side of it

wasn’t working properly.Once at the game, therewas a red border around


the N-Compass display.This indicated a “SentinelTO System” problem. If thedisplay had had a yellowborder, the problem wouldbe a “Game TO Sentinel”issue. Since this one had ared border, I first looked atthe CAT5 cable on theSentinel; the COM lightswere dead. Next, I took alook at the computerswitch. It was lit up like acasino sign, lights all overthe place. When lookingcloser, I noticed that one ofthe channel lights was notlit and a cable wasn’tplugged in all the way.After it was snug in place,the channel light (for ex-ample, number six) lit upas did the lights on theSentinel CAT5 connection.After taking the game“offline” then putting itback “online” with my glo-bal card, no more red bor-der. Everything lookedgood. I even doublechecked and pressed the“diagnostics tab” on the N-Compass display to verifyeverything had communica-tion, which it did. The prob-lem was simply a looseCAT5 cable on the com-puter switch.

When the project was firststarted, on our first bank ofgames, all of them didn’taccept “promo cash” unlessthe Sentinel was rebootedAFTER it was totally set upand working. After every-thing was globalled, hadcommunication and lookedgood, they needed to berebooted otherwise a “gen-eral error” appeared when

attempting to downloadpromo cash. With the “me-chanic card” or global card,there is a tab that evenstates “reboot”. Simplytouch the reboot tab. Thereis no need to physicallypower cycle the Sentinel.

If there are unusual IPaddress numbers on the N-Compass displays, thecomputer switch may needa power cycle. If a powercycle doesn’t do it andEVERYTHING else looksnormal, the IT department(Information TechnologyAKA computer geeks) mayneed to be called to checkout the switch. They dowhatever they do and thencommunication can beestablished with the games.

Editor’s Note: Really? YourIT department actuallytouches the HARDWARE atyour casino, Pat? Forgivemy ignorance in this re-gard. Question to readers:At your property, do your ITfolks do anything withhardware? I was once at acasino (helping them builda nice shop) when theysuffered a failure of theirmail server. Even THATrequired a repair courtesyof the slot department.After all, who else in acasino environment knowshow to do this kind of stuff?The slot department totallyROCKS the casino from an“electronics repair” point-of-view, no?

IGT Trimline Was ShutIGT Trimline Was ShutIGT Trimline Was ShutIGT Trimline Was ShutIGT Trimline Was ShutOff, Unknown ReasonOff, Unknown ReasonOff, Unknown ReasonOff, Unknown ReasonOff, Unknown Reason

I was checking out thingsduring a morning walk onthe gaming floor to see ifany interior casino signageneeded attention, if slotbase lights were all lit or ifany games were turned offthat I was unaware of andnot in our log book. It israre but it does happen.There was an IGT Trimlinegame that was turned offbut nothing was in the logbook. The previous shifthadn’t pass down any infor-mation and I didn’t see awork order for it. Who shutif off and why was it off?

Oasis diagnostics monitor,entering in the machinenumber, under the transac-tions tab, could have beenused to see whose em-ployee floor card was last inthe game. Instead of track-ing information on thegame, I just checked it out.

As soon as power wasturned ON, there was anunusual vibration comingfrom the game. It was simi-lar to a cell phone vibrationbut at a slower rate. Whatcould cause it? A bad cool-ing fan. After disconnectingone at a time, I found outthe fan located on the up-per right side, behind themain LCD was bad. Oncedisconnected, no morevibration. Since gamesdon’t really like any itemsplugged in with power on, itwas power cycled a fewtimes for troubleshooting.On the first couple of power


ups, boot up was normal.This time, the screen frozeup on the AVP logo. An-other power cycle ended upwith the same result. Aftertaking a look at the videocard (which had a bad fan) Iblew out the brain box withcompressed air along withcleaning the brain box airfilter. A new type of videocard was installed that hada black heat sink aroundthe fan. The original onehad silver heat sink butother than that, theylooked pretty similar. But,the game didn’t like it.Once again it would notboot up properly. So anexact looking replacementwas installed. I thoughtmaybe it was an upgradedcard, no such luck though.Next, the exact OEM (Origi-nal Equipment Manufac-turer) was installed and thegame booted up perfectly.Promo cash was down-loaded, the game wasplayed for a couple of min-utes, a few other thingswere checked just to makesure all was good, such asgame to system communi-cation, buttons, and such.Everything looked fine.

IGT S AVP “Host Offline”IGT S AVP “Host Offline”IGT S AVP “Host Offline”IGT S AVP “Host Offline”IGT S AVP “Host Offline”ErrorErrorErrorErrorError

I received a call about threeIGT S AVP “Wheel of For-tune” games that had a“host offline” error. My firstthought was a loose fiberoptic cable connection butwhen looking at both of thegame “COM boards” neitherwere lit up at all. Normallyboth the red and green

lights flash rapidly to indi-cate communication. Sinceone game had dead com-munication boards, itknocked down the othertwo. Since all three of the$1.00 “Wheel of Fortune”are linked together, whenone part of communicationgoes down, they all do. Whywere both COM boardsdead? A game reboot didn’thelp at all but when doingwhat I call a “hard boot”(when main power is dis-connected from the gamefor about 15 seconds) some-thing unusual happened.The game interior servicelight flickered after the110vac connector was snugin place. A slight wiggle ofthe “110vac power supply”(110vac plugs into it, thetracking system powerplugs into it, and it has aconnector located on theback in which plugs intothe game.) This told me thepower supply had a looseconnection, also verified by

a loose thumbscrew that issupposed to hold it inplace. After the screw wastightened down I tried towiggle the power supplyonce again. Now interiorlight didn’t flicker, it wassnug in place. After thegame booted up all gamescleared the “host offline”error. Simply a loose powersupply was the problem.

- Pat Porath - Pat Porath - Pat Porath - Pat Porath - Pat [email protected]@[email protected]@[email protected]

CHEAP ADVERTISING

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619.838.7111 or emailadvertising@slot-

techs.com


Slot Tech Herschel Peeler Bonus!

If you have spent anytime at all looking at theUNI-750-1 schematic you

no doubt have noticed themess of lines just after themain rectifier. You also mayhave wasted time ponderingwhat appears to be a fullwave rectifier circuit withtwo diodes but no center-tapped secondary. SETECdoes seem to like designingstuff. What could have beena simple and straightforward design they made… complicated.

Let’s start this show by

redrawing the circuit thentaking it apart to see how itworks. I have no idea whatthey had in mind by all thezig-zag lines. But taking anohm meter and a close lookat the circuit, Figure 1 iswhat you find. Not toosurprising actually.

Next we realize theresistors and capacitorsacross the rectifiers are justde-glitch filters. Takingthem out of the circuit weget Figure 2. R71 and R72are part of the Temperaturecircuit. We will get to thatlater. Let’s take them out of

the circuit for now also. Sohow does what’s left work?

Figure 3 shows what wehave going on when the 24Volt secondary of T2 hasthe positive cycle (+ to thetop of the drawing as shownin Figure 3). Current leavesthe negative side of T2,down through the choke(L5) and up through C3and the 24 Volt load, backto T2 through the toprectifier of D7. We now haveL5 and C3 charged up.

Figure 4 shows what

UNI-750-1 24 Volt Section


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happens on the next halfcycle. The inductordischarges, pushing in thesame direction as theoriginal current, asinductors do. C3 dischargespushing current in theopposite direction as whenit was charging, ascapacitors do. Both pushcurrent through the 24 VLoad and back to D7. Thistime the top rectifier isreverse biased andessentially out of the circuitbut the lower diode is nowforward biased and currentreturns to the other side ofL5. The transformer isdoing nothing.

The 12 and 15 Volt sectionswork in a similar fashion.On the positive cycle onediode conducts, suppliespower to the load andcharges the inductor andcapacitors. On the negativecycle the load is powered bythe inductor dischargingthrough the other diode.

Capacitors dischargingadds to the power suppliedto the load.

- Herschel Peeler - Herschel Peeler - Herschel Peeler - Herschel Peeler - Herschel Peeler

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