Star Tech Journal

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.