Star Tech Journal

SNK POW PCB Modification
Neal Zook
SNK Corporation of America
Sunnyvale, California
MODIFICATION
NOTE
SNK Corporation of America would like to
inform field service personnel of a modifica-
tion to the Prisoners of War PCB. The modi-
fications to the PCB consist of adding two or
three resistors onto the PCB to ensure
proper operation. This modification corrects
the following symptoms:
Please check the access time rating of the
Main Program Eproms DG 1 and DG2. These
Eproms must be 200 nsec (or faster) devices.
The access time rating can be determined by
the suffIXlisted on the device. Refer to the list
below for suitable devices. If your PCB has
Roms that are not listed below, or have -25
suffIXes, please contact SNK's Customer
Service department to get further informa-
tion or replacement Roms;
• Intermittent lock-up during Attract Mode
and Game Play Mode
• Games switches to Game Play Mode while
in Attract Mode
• Pressing Start to continue current game
deducts credits, does not start game
• Punch and Kick sounds go away during
game play
PROCEDURE
If your game experiences these symptoms,
please check and/ or add the following
modifications to the Prisoners of War PCB:
Mod 1 - Add a lK ohm 1 / 4 watt resistor from
pin 25 to pin 28 of HM6264 Ram at location
12K. If this resistor is already installed,
check the quality of the soldering as this may
have a bad solder connection.
If you have any questions regarding Prison-
ers of War or these modifications, please
contact SNK's Customer Service depart-
ment Monday thru Friday between 8:00 am
to 5:00 pm Pacific Time at (408) 736-8844.
Mod 2 - Add a lK ohm 1 / 4 watt resistor from
pin 6 to pin 16 of 7 4LS 15 7 at location l 5R.
If this resistor is already installed, check the
quality of the soldering as this may have a
bad solder connection.
Mod 2a - If the 7 4LS 157 at location l 5R was
produced by Motorola (as identified by the
"M" logo on the device), add another lKohm
1/4 watt resistor from.pin 10 to pin 16.
Murphy's Law #109