Star Tech Journal

Issue: 1986-August - Vol 8 Issue 6

STAA*TECH Journal
Getting Negative Voltages
From switching Regulators
By James Beck
Greater Southern Dist. Co.
Atlanta, GA
Hello again, didn't quite make it in last
nonth' s issue, but I'm back again. As
pranised, we will cover methods of getting
negative voltages from switching
regulators that only offer positive
outputs.
August 1986 (8)
F,~.i.
~/c.
V+
~~T
()~
e."
1.-V
Vcu'T
c.-t--
The main problem that is encountered with
attenpting to accooplish this, is the fact
that switchers use high-frequency pulses
to operate. Standard techniques, like we
covered in the previous nonths, won't work
all that well. M:>st rectifiers work OK at
60 Hz, but at 15 KHz and up, they tend to
·leak backwards across the junction.
V+
Fortunately in this age of the
semiconductors ;mere there is a problem,
someone has come up with a solution.
In steps the ICL7660. This wonderful
little chip takes a positive input and
converts it to an equal voltage of
opposite polarity. Fig. 1 shows the pin
out of the chip. All that is needed to
make it function are 2 capacitors and a
diode.
The typical efficiency of the device is
well above 95%. The value of the
capacitors is not critical; I have had
great results using lOuf caps. '!be output
current is low, but -can easily power
dynamic RAMs and OPanps. It may not work
with some of the newer games that use
hybrid custom chips for the RGB
generation. These hybrids suck up a lot of
current.
Fig. 2 shows the configuration for
converting voltages under 3.SV and Fig. 3
shows the configuration for converting
voltages g~eater than 3.SV. The whole unit
can be asseubled on a Perf Boa.rd in under
15 minutes and the chip can be purchased
for less than $4.
well, I haven't come up with a topic for
next DDnth as of yet, so if anyone has any
suggestions -give me a call at
. 404/352-3040.
V+
1--..::::..t__t--M----,--• -YoJt
:f'\~~
"'
COIN-OP NAIL LISTI
USAr Over 11,000 names of coin-operated
equipment owners, operators, technicians,
suppliers, Jobbers and distributors.
Newly updated. 8575.
EUROPE& Over 2,500 large operators and
distributors of coin-op equipment. 8300.
Lists era supplied
labels in zip-coda
deliverable. Order
JOURNAL, PDB 1065,
on praaaura-sanaitiva
order. Guaranteed 931
from1 STAR*TECH •
Merchantville NJ 08109.
August 1986 (9)
STAR*TECH Journal
>>>>>>>>
NARICETPLACE
<<<<<<<<
A monthly listing of available coin-op
sales and services seen by over 2,000
amusement machine operators.
MARKETPLACE prices are $4 per line, (two
l he minimum), with a maximum of 40
characters per line -including spaces.
DEADLINE: The 20th of the previous month.
(Example: August 20th for the September
issue.) Cell 609/662-1080.
Control Panel Brapbtcs ••• Restore or
convert your video game control panel with
this fabulous new kitl Includes a thick,
durable overlay, over 100 different
stick-on labels and a thick transparent
protective covering. For FREE sample and
ordering info call or write: CONTROL PANEL
GRAPHICS, PO Box 64-0366, Miami, FL 33164.
Phone: 305/769-1082.
For Sala1 Used Coin-op kiddie rides.
CM KNIGHT, Route 1, Box 320, McCormick,
SC 29835. Phone: 803/443-2607.
Used ~tddta Ride Naada. Fiberglass motor
cycle replacements: Seats, gas tanks,
Sandy & Altech fiberglass bases. Clean up
carousels with: Decal Striping Kit, Steer-
ing wheels -4" & 8", Security covers,
pins, & round locks. KIDDIE AMUSEMENTS,
POB 939, Florence, MS 39073. In Southern
USA 800/647-6460, elsewhere 601/845-7501.
Conversion Kit -three games
in one cabinet! Kit includes; Switching
circuit, wire harness, marquee and game
instructions $235. Call: 814/234-3209.
Pro Circuitry, State College, PA.
Nulti-SJata ■
Quality Harn••••• for Video Games $15.00
& up. Del: 5-7 days. Special harnesses
upon request. Color conversion kits for
Donkey Kong, Mario Bros, Popeye, permit-
ting use of Monitors for normal conversion
-$18.00. Rejuvenate Ms. Pecman and Gelaga
with Speed-up and Rapid Fire Eprom change.
Write/call Louise's Harness Shop, Rt. 3,
Box 7~, Prattville, AL 36067*205/365-1841.
STAR•TECH JOURNAL Subscription
For ■
New Subscription: Please initiate my
subscription to STAR*TECH Journal for the
period indicated:
USA1
<>1 Yr $56
<>2 Yrs $98
<>3 Yrs $142
Canada/Naxico1
<>1 Yr $63 <>2 Yrs $110
<>3 Yrs $160
Foraign1
<>1 Yr $98
<>3 Yrs $249
<>2 Yrs $172
Subscriptions to North America are mailed
via First Class Mail. Foreign
subscriptions are mailed via Air Mail.
Company:
Wantad1 Pilasters for Wurlitzer 1800
$5D. ea. GLOBE 378 Granite St, Quincy, MA
Legal Salaga for $199. Converts Atari
Dig Dug P.C. boards into Galage. 24 hour
turnaround. A.P. ENGINEERING 714/989-1243.
1917 Huntington Street, Suite 3,
Huntington Beach, CA 92648
Su ■■ ar Daya Sala, Bargain Basement
Prices! Wico Joysticks $5, Micro Joy-
sticks $3. 1,000 1 s of buttons, power
supplies, Eproms, ICs, etc. Marquees $1
end up, overlays $3 and up. We've bought
out MAGIC ELECTRONICS! Clearance sale,
call for details. Pinball parts by the
1,000 1 s -bumbers, plexies, playfields.
Antique Jukebox perts. Call Cindy in
Perts and she'll make the deal. HI-TECH
COIN MACHINE, 315/455-5881. POB 298, 1800
Brewerton Rd., Syracuse, NY 13211.
BEST IN USED VIDEOS
Crossbow ....... .
Commando ...... .
Excitebike ....... .
Gauntlet ........ .
Gunsmoke ...... .
Hat Trick ........ .
Jailbreak ........ .
Hogans Alley .... .
Karate Champ ... .
Kung Fu Master .. .
Paperboy ........ .
Punch Out ....... .
Spy Hunter ...... .
Super B.B. ....... .
VS. Golf ......... .
Space Harrier .... .
Hang On ........ .
$996
1395
895
2095
995
1495
995
995
895
1095
1995
795
1495
395
895
2495
2595
Call for Latest
Prices on Conversions·
Rygar ......... 1050
Gladiator.. . . . . 995
Tokio ........ . 925
Trojan ....... . 925
Super Mario .. . 275
Gumshoe .... . 325
Mania
Challenge . . . . Call
World Series ... 1095
Guardian . . . . . . 625
Sky Kid . . . . . . . 625
Merchandising Equip.
Special
Big Choice
Singk Cranes
CALL WHILE THEY LA C.T
Attn:
ALPHA-OMEGA-SALES
Address:
Call Marty or Frank "The Crank"
City:
State:
Nintendo RP2AD8 $150 w/purchese of
DUAL/UNI (2 cabs side by side) kit price
$195 or Dual UNI/VERSUS (2 peke 1 cab) kit
price $175. Call Kathy 818/308-3717.
6 Sutton Place • Edison, NJ 08817
Zip:
The Operator's First Choice
201-287-4990

Download Page 8: PDF File | Image

Download Page 9 PDF File | Image

Future scanning projects are planned by the International Arcade Museum Library (IAML).

Pro Tip: You can flip pages on the issue easily by using the left and right arrow keys on your keyboard.