Star Tech Journal

Issue: 1983-July - Vol 5 Issue 5

22
STAR*TECH JOURNAL/JULY 1983
"The 'Bear' Facts" continued from page 21.
The 7 4C90 has 4 flip-flops, 6 NAND gates and 2 inverters inside. The logic
schematic looks like this:
E to F would be a filtered DC waveform looking like this:
oc----------------
Ain
Ov ---------------- -----
o
As you see, the wave form of the filtered unit is still very unsteady.
A much better rectifier is a full wave bridge. This rectifier is as follows:
a
S R1
a
CLK
a
0
R2
B
CLK
Q
o
a
S R1
R2
0
Your wave form at points A to B without the rest of the circuit will be:
- ~ - -
So, if this is all there is to a Divid-by-Counter, you probably can figure that,
YES!!! you can build Divide-by-Counters using simple JK Flip-flops!
Here's how:
Your wave form at points C to D will be as follows:
OC---------
Ov ____ - ____ - - - - --
Now if your line voltage were to drop, so would your DC voltage, and when
working with logic family circuits, you just can't have that! So, the next step
is to have a regulator in your circuit Since we are talking about 12vdc
circuits (mostly) in this column, let's use a+ 12-volt regulator called a 7812.
The 7812 is capable of having upto I amp run through it which is plenty for
most logic boards. ( 12 watts is a lot of power for a logic board!) What the
regulator does is this: It takes an input of up to 35 vdc and regulates it down to
12vdc.
30
: :
'"1" I
~
0
Ok, now that you've done each step, put them all together and you've got:
~
J!!.
2
In
28.75vac
12vdc
12vdc
a
15
6
a
14
5
K
12
3 CLK
-
Voltage at points A to Breads +30vdc
Voltage at points C to D reads + 12vdc
115vac
0ivid&-by-3
V00
-
CLK
13
I~
10
l!l
a
J
3
K
a CLK
3
-
Divide-by-4s and Ss are similar. So, as you start troubleshooting score
displays and coin/game count circuits, remember that"-they all work
similarly and this is the basic theory behind the operation of such circuits.
o=-----•---- -1..---0-- B
Oivid&-by-2
voo
MotOf
t - - - -...... - - -.....
Your 12vdc regulated power supply!
Ok, I'm sure that most of you have used ohms law and the power laws,
and have learned them fairly well, but for you future technicians that are lost
when I mention these formulae, this is what we are talking about
Ohms law is the most useful formula in all of electronics! It reads as
follows: E (energy or voltage)= I (current)· R(resistance). Another useful
formula is P (power)= I (current)· E (energy or voltage). This last formula
is known as PIE. So, with these two formulae, you can move everything
around using algebra well enough to find every combination. As long as you
have two variables, the third and fourth can be found! Since a lot of you don't
know algebra, I'm going to give you the "PIE DISH". Keep it everywhere
and you'll never get stuck for a formula.
The center quadrant letter represents the value you're hunting and the
formulae on the outside ring equate how you get the answer.
P = Power, I= Current, R = Resistance, E = Energy or Voltage.
Ok, time to get complicated!
We've talked about counters like the4017 and the 74C90. Now let's see
what's making them work!
This month I'm going to be really skimpy on reviews as next month's column
is going to run extremely long.
First, some information has been given to me by Jim Augeri ofSkeeball.
Jim designed the ticket dispensing drive circuit used on Audio Skeeball and
has released some more information to me regarding the fiber problem on the
photo optic switch ticket count circuit
I . National tickets have much cleaner ( fiber dust free) ticket paper than
Globe tickets. If you must use Globe tickets, check them to see which side
most of the fiber dust is on and insert your tickets so that the cleanest side
passes through the optic switch.
2. The Audio Skeeball has a I Ok resistor on the dispenser motor driver
board that can go clear up to 20k to make the optic switch more sensitive.
But, some ticket brands are so thin that wnen the optic switch is made this
sensitive, the optic switch will read nght through the ticket! So, experiment
and feel free to call Skeeball if you have any questions.
Next month I will have a ton of information from Superball Corp. on all
the retrofit units that they have designed that will work on all ball roll-type
games!
Vending International released their first cotton candy vendor units about
eight months ago and the units have been found to have two major weak
spots. Both have corrections and I want anyone who has the unit to be made
aware ofit
The major problem was in the Iron Pot Spinner Assembly. This has been
redesigned and all units can be retrofitted at no charge simply by calling
1-800/821-8990.
The symptoms were: The lower bearing going bad and a short to ground
developing in the AC heater circuit causing the heater band to bum up. The
newly redesigned assembly eliminates both problems.
The second problem was discovered at a Showbiz Pizza Place location
that had people standing twenty deep to buy a cotton candy. When the unit
was run continuously, there was a heat build-up problem in the Iron Pot
Assembly that caused the cotton candy to be shaped improperly.
The correction for this problem is a new EPROM with a 10-second
cooling spin cycle added into each vend. That takes care of the heat problem!
If anyone has any questions concerning this or any non-video unit, give
me a call at 1-800/821-8990.
Well, Peter Gurko of Kiddie Rides U.S.A. has been as tied up as myself this
month, but he did manage to get some info out to me, so once again, here's
Peter ... (P.S. Thanks, Peter!)
Continued on page 25.
23
STAR*TECH JOURNAL/JULY 1983
I
~VIDEO
~GAME
TROUBLESHOmNG
GUIDE
Listed here are seven technical schools available to our industry throughout the country.
Each school returned our "S•TJ School Questionnaire" providing all the i,iformation that
follows. For additional i,iformation, call or write to the indillidual technical schools
listed here.
Banner Technical Trade School, Inc.,
721 Benjamin Fox Pavilion, Jenkintown, PA
19046. 215/572-6966
Courses offered: Electronic Amusement
Repair I: Basic Electronics, Video Game
Systems, Monitors, Electronic Pinball Systems,
Troubleshooting Techniques, Test Equipment,
Schematic Reading, Safety Instructions.
Length of course: 5 days. 9:00 am - 5:00 pm.
Monday-Friday.
General outline of subjects: Electron Theory,
Semiconductors, Power Supplies, Control Panel
Interfaces, Raster Scan and X-Y Monitors,
Electronic Digital Systems, Troubleshooting
Techniques, using the latest equipment.
Tuition: $475 per student. $100 deposit.
Entrance requirements: A desire to learn. No
previous experience in electronics or game
repair is required.
Certificates/Diplomas awarded: Certificate of
completion to those who successfully complete
this course.
State/ Association accreditation: Licensed by
the Pennsylvania, Maryland and Virginia State
Boards of Private Trade Schools.
Cal's Coln College, P.O. Box 810, Nicoma
Park, OK 73066. 405/769-5343
Courses offered: 2-week course covers videos
and pins.
General outline of subjects: Schematics, Dis-
crete Components, Power Supplies, I Cs, Seven
Monitors. Pinball Circuits and Video Circuits.
Tuition: $700/2 weeks.
Entrance requirements: A desire to learn! No
prior electronic or electrical training is required.
Certificates/Diplomas awarded: Certificate on
successful completion.
State/ Association accreditation: Member
A.M.O.A., Certified Oklahoma Board of
Private Schools, bonded.
Electronic Institute of Brooklyn, 4801
Avenue N, Brooklyn, NY 11234.
800/221-0834, 212/377-0369
Courses offered: Classroom Video Game
Repair Course ( Complete-Analog & Digital).
Video Tape Home Study Course (same as
classroom material).
Length of courses: 60 hours/2 evenings a week
7:00 pm- 11 :00 pm. Video Tape Home Study
Course can be viewed at your own pace.
Approximately 30 hrs.fl O tapes, VHS or Beta.
General outline of subjects: Classroom: Basic
Electronics, Using a Digital Meter, Power
Supplies, B/W Monitors, Color Monitors, B/W
& Color X-Y Monitors, Basic Logic, Using a
Logic Probe, Pinball Repairs, Video Game
Repairs. Video Tape Home Study: Same as
classroom outline.
Tuition: Classroom: $800/$25 deposit Balance
paid during 5 weeks of the course. Video Tape
Home Study: $300.
Entrance requirements: Little or no electronics
background.
Nevada Gaming School, 3100 Sirius,
Las Vegas, NV 89102. 702/873-2345
Courses offered· (I) Gaming & Amusement
Machine Technician Program. (2) Amusement
Machine Technician Program. (3) Slot Machine
Technician Program.
Length of courses: (1) 700 hrs./7 weeks. (2)
500 hrs./5 weeks. (3) 400 hrs./4 weeks.
General outline of subjects: Basic Electro/
Mechanical Theory/Lab. Advanced Electro/
Mechanical Functions. Video Game Theory/
Lab. COURSE OBJECTIVE: To equip the
graduate with the entry level skills and know-
ledge necessary to meet the requirements of the
Gaming and Amusement Machine Industry.
The essential skills are developed through a
combination of classroom lecture, problem
solving and actual "hands-on" application of
attained knowledge.
Tuition: (I) $3,800 (2) $3,250. (3) $2,150.
Entrance requirements: Ability to pass the
School Aptitude Test.
Certificates/Diplomas awarded: Diploma.
State/ Association accreditation: Accredited
by the National Association of Trade & Tech-
nical Schools. Licensed by the Nevada
Commission on Postsecondary Education.
Endorsements: VA; State Industrial Insurance
System; Comprehensive Employment and
Training Act; Nevada Bureau of Vocational
Rehabilitation.
Randy Fromm's Arcade School, 6123
El Cajon Blvd., San Diego, CA 92115.
Courses offered: Beginning to intermediate
entry level course in electronic game repair.
Length of course: Six days/approximately 8
hours per day.
General outline of subjects: Introduction to
Basic Electronics. Using the Digital Multimeter,
Understanding Semiconductors, Power Supply
Operation and Repair, Video Game Monitor
Operation and Repair, X-Y Monitor Operation
and Repair, Troubleshooting Sound Systems,
Soldering Techniques.
Tuition: $500.
Entrance requirements: Minimum age: 18
years. No previous experience required.
Certificates/Diplomas awarded: Diploma
awarded upon graduation. Exceptional gradu-
ates earn the "CERTIFICATE OF
EXCELLENCE".
Endorsements: Officially approved for coin-op
repair training by the Ohio and Wisconsin
Amusement Operators Associations and the
California Dept of Rehabilitation.
Sta'*Tech Journal's Distributor-
Sponsored Technical Seminar &
Workshop. Distributor's choice oflocation/
nationwide. To sponsor or for information,
contact Star*Tech Journal, P.O. Box 1065,
Merchantville, NJ 08109,. 609/662-3432
Courses offered: Electronic Game Repair:
Field Service Course designed to enable entry-
FOR
VIDEO
GAMES
•CUTTO THE PROBLEM IN SECONDS
• EASY TO UNDERSTAND
• DESIGNED FOR OPERATORS,
ARCADE OWNERS & TECHNICIANS
• LAMINATED FOR DURABILITY
• UNCONDITIONAL MONEY BACK
GUARANTEE
CHECK OR
MONEY ORDER OR
SEND

COD
$12 95
VIDEO
I TROUBLESHOOTING
I
GUIDE
Please send
VIDEO CHARTS.
TOTAL ENCLOSED
: RICH~5Nt, ~tio85 SHIP. CHG. INC.
TO SEND C.O.D. CALL 816/776-5938
I
I
NAME---------
ADDRESS,_________
I
I
L.....:'~~E/!'., ________ J
level technicians to isolate and repair 85% of
game failures on location.
Length of course: 5 days, 9:00 am - 5:00 pm,
Monday-Friday.
General outline of subjects: Electron Theory
& Semiconductors, Video Game Power Sup-
plies, Control Panel Interfaces, Raster-Scan
and X-Y Monitors, Electronic Digital Systems
for Pinballs. Troubleshooting Techniques. Use
of test equipment Proper soldering/ de soldering
techniques. Analyzing electronic schematics.
Tuition: $450 per student. $100 deposit.
Entrance requirements: Designed for the
operator's service people with a minimum of
electronics experience.
Certificates/Diplomas awarded· Certificate of
completion.
Vldeotronlx Training Center, 705 N.
Bowser, Suite 108, Richardson, TX 75081
(suburb of Dallas). 214/231-3307
Courses offered: Basic, practical electronic
game machine repair - designed to fit client's
needs.
Length of course: One, two, or three day
seminars or six day course.
General outline of subjects: Basic (Game--
Oriented) Electronics, Power Supplies, Moni-
tors, Intro & Overview of PCBs. Use of
Volt/Ohm Meter.
Tuition: Approx. $100/day.
Entrance requirements: Willingness .to learn.
Certificates/Diplomas awarded: Certificate of
completion.

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