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STAR•TECH JOURNAL/AUGUST 1982
SERVICE 'l'IPS:
GREMLIN/SEGA "TURBO" OPTICS
MIDWAY "GALAGA" FREE PLAY SOLUTION
By Howard M. Smith, B & B Vending, Dallas, TX
Gremlin/Sega's "Turbo"
Optical Coupler Replacements
A recent shortage of the PS4001 optical coupler
used in Gremlin's "Turbo" steering board resulted in
a fruitless search for a second source for the part.
The SPX 1879-11 couplers used by Bally in the
"Gorf' optical board are almost the same size
physically, but will not work reliably without circuit
modification.
The best interim fix we could find was to use the OPB
2208 coupler used in the Atari steering boards. This
device is a dual coupler unit, but can be cut in half on
a handsaw or with a hacksaw, resulting in two
couplers that work very well on the "Turbo" steering
board.
The longest curved segment of the Atari coupler
contains the light source and should be positioned on
the "Turbo" board above the holes marked "A" and
"K".
Midway "Galaga" Free Games
By Pounding On Door
Midway games have always had a tendency to pinch
the coin door wiring harness in the hinge or in front of
the cashbox. Anytime there is a problem of free-play
or resetting, this harness should be carefully inspected
for nicks in the insulation.
Midway has started using a plastic ty-wrap to lace
the harness to the coin door under one of the coin
return cups. These ty-wraps should have been
tightened only enough to keep the harness from
sagging in front of the lip of the door, but many of
them were cinched down all the way.
It is only a matter of time before these wires will be
cut by the sharp edge of the coin return cup. If this
happens, the game could reset or give free credits
when the door is stressed by a sharp blow.
The solution is to cut the ty-wrap, tape up the wires
and tie them back loosely with another ty-wrap or a
piece of wire. Then make sure the wires to the coin
switches are dressed up behind the switches so they
can't get pinched in the door.
EXIDY
TECHNICAL 'l'IPS
"VENTURE" TO "PEPPER 11" CONVERSION
WELLS-GARDNER COLOR X-Y DISPLAY
Exidy is now offering a complete modification kit, to
upgrade "Venture" games to "Pepper II". The kit
contains everything needed, including EPROMs,
controls, cabinet side art, and plexiglass art. Exidy
feels this modification will vastly increase game
earnings as well as generate excitement over the
newest of their games.
The Modification Kit is available for a reasonable
cost through any Exidy Distributor.
For more information, contact
Exidy,
390 Java Drive, Sunnyvale, CA 94086.
Phone: 408/734-9410.
Symptom: After replacing a shorted transistor in
the +28-volt power supply (QlOO or Ql02), the 5-
amp fuse blows again.
Cause: You probably have shorted diodes ZDlOO
and D 104. After replacing a defective component, it
is always good practice to check all components in
the power supply prior to power up.
The same applies to the -28-voltage power supply
components QlOl, Q103, ZD101 and D105.
Symptom: Glitches or spikes on video display
objects.
Cause: Defective components C901 and C902
capacitors located on the circuit board in the high
voltage cage. Recommended replacement is a 100
uF, 50v electrolytic capacitor.
Star•Tech Journal, Volume 4, Number 6, August 1982. Copyright 1982 by Star•Tech Journal, Inc. All rights reserved. Star•Tech Journal is published 12 times a year.
Address inquiries to: P.O. Box 1065, Merchantville, New Jersey 08109. Phone: 609-662·3432. Star•Tech Journal verifies the contents of the articles herein as much as
possible, however, any reader using this information does so at his/her own risk. Star•Tech Journal accepts no responsibility for Its advertisers' activities. Subscription rates:
U.S.A.·$32.00. Canada-$36.00. OtnerCountries-$56.00. Please remit payment In U.S. funds. Advertlsin!I rates available upon request. Staff: Publlsher/Editor:JamesCalore,
Administrative Assistant: L.T. DIRenzo. Art/Advertising Coordinator: Paul Ehlinger. Circulation Promotion: Linda Geseklng. Contributing Technical Writers: Todd Erickson,
Joe Connor.