Star Tech Journal

Issue: 1989-January - Vol 10 Issue 11

Merit Pit Boss II &
Super Video Mod
Atari Rolling
Thunder Audio Fix
Jim Kelly, Service Manager
Merit Industries
Bensalem, Pennsylvania
Philip Del Grosso
Alpha Amusements, Inc.
Warren, Michigan
PROBLEM
The CRT-250 PCB's used in Super Pit Boss
and Pit Boss II can experience logic lock-up.
The video screen goes black intermittently
on power-up or during the attract mode.
SYMPTOM
Game missing vocal sounds and some firing
sounds.
SOLUTION
Add one 330 ohm, 1 / 4 watt resistor to the
CPU oscillator input of the CRT-250 PCB.
Solder this resistor between Pin 6 of U 1
(CPU) and Pin 20 ofU4 on the solder side of
PCB.
NOTE
All these games should be checked for the
latest program updates (Eproms). Pit Boss II
(9221-01 U9-OB), Super Pit Boss (9221-02
U9-0A). In conjunction, this resistor modifi-
cation should be done. If there are any
questions about this update or any Merit
products, call Customer Service at 800 /
445-9353.
CONDITION
On Rolling Thunder Sub PCB Assy., +5v is
present at the Eproms. However, a voltage
check on A3 (6770 IX) reveals that the Audio
supply voltage, AV cc, is only 1.4v.
CAUSE
The schematic shows that the +5v source is
split and the AV cc is sourced through a 100
Mh inductor, which has opened up, and
when an OHM check is done, shows high
resistance in the MEG OHM range.
SOLUTION
After replacing the inductor, AVcc is re-
established, and the game vocal sounds are
returned.
Drew's Software Versions
Service Department
Drew's Distributing
Fairforest, South Carolina
CURRENT SOFTWARE VERSIONS
Honest Dealer
Super Bonus Deluxe
Tiger Paw
V-2.96
V-2.89
V-3.810
Current version Eproms can be ordered
from our parts department at a cost of
$25.00 each.
WG 19K7901
InterDlittent Fix
CoDlpany Rebuilds
Sega Motors
Philip Del Grosso
Alpha Amusements, Inc.
Warren, Michigan
Bill Eaton
GAMES
After Burner U /R, Top Speed and all other
SUBJECT
games that use the Wells Gardner model
19K 7901 monitor.
PROBLEM
Games comes on ok, but after period of time
the picture goes blank. Logic and power are
present, but no filament voltage can be seen
in the neck of the CRT.
SYMPTOMS
This can be a very nagging and annoying
problem because often times the game will
seem to work fme, then when moved on
location, or left on, the monitor will go out. I
first suspected that the over-voltage protec-
tion had kicked in due to high line voltage.
CAUSE
However, this is not the case. I removed the
monitor chassis and gave it a physical exam
and noticed that on Tl, the high voltage
transformer, Pin 1 had broken loose from the
solder pad and was making an intermittent
contact with pad.
NDI
Laguna Hills, California
For those of you who seem to have trouble
getting your Sega Motors rebuilt, try this
company:
Santa Ana Electric Motors
2225 West 2nd Street
Santa Ana, CA. 92703
714/543-9401
Ask for Steve Knowles. They will rebuild
most Sega motors (COD only ... ). It's alo~
cheaper than buying a new motor!
Drew's Joker Poker
54 Dix Conversion
Service Department
Drew's Distributing
Fairforest, South Carolina
SOLUTION
PROBLEM
I re-established a good solder connection
with this pad, and with some of the other
pads, which seemed to be breaking loose
and I have had no problems since. This
problem has happened to 3 of the U /R After
Burners, and 2 of the Top Speed monitors,
possibly because of the high amount of
vibration and current demands put on these
pads by these games.
Cheating problems with Drew's
Joker Poker 54.
SOLUTION
We strongly recommend the Joker Poker 54
Deluxe conversion. This includes 5 Eproms~
1 PAL and labor. All boards must be sent to
us for this procedure. Contact Drew's for
further information and pricing.

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