Star Tech Journal

August 1988
Kranier High Speed
Bonus Diode Mod
Drew's Card Ganies e
Power Supply Adj
Ronnie Belitz
Lark Amusement Inc.
Bristol, Tennessee
Service Department
Drew's Distributing Co., Inc.
Fairforest, South Carolina
SYMPTOM
Coin lock-out coils and front panel lights fail
and/ or game goes into a reset condition after
several hours of operation.
PROBLEM
We have experienced complaints of white
screens on our card games. While each game
is checked here, it never hurts to check and
be sure.
CAUSE
Recent shipment of these games have Dl0
and D9 used in the power supply inter-
changed. Dl0 is a 1N4750B/28V zener
diode and should have the cathode tied to
the base of Ql and D9 is a 1N4148 diode in
series with Dl0.
CURE
Remove D 10 and D9 and interchange.
COMMENT
When these diodes are incorrectly installed,
it allows 45V to reach the LM7824 and the
LM7812 regulators -causing them to shut
down due to overheating. When the diodes
are installed correctly, the voltage
to the regulators should be 28V.
SOLUTION
Set the power supply on all of our card games
at 5.30vdc +/- .05v. This is best accom-
plished with a digital multimeter.
PROCEDURE
Look at the top of the power supply from th: e
back of the game. Select the 20 volt de scale
on the multimeter. Connect the black test
lead to any of the three black wires coming
out of the top of the power supply. Put the red
test lead in the socket that has the white with
red stripe wire coming from it. Adjust the
potentiometer until the multimeter reads
5.30vdc +/- .05 volts.
Data East Heavy Barrel Video Wave
John M. Bevar, Service Technician
Ries Amusement Inc.
Denison, Iowa
SUBJECT
Wavy lines in picture.
SYMPTOM
New game kit when installed develops wiggly
e
lines and cannot be adjusted out. A conflict
of grounds exists.
SOLUTION
Remove the earth ground strap going to the
monitor chassis.