_ _ 4 _ _ _ _ srAR*7ECH
JOURM,..4., ____________________ .;,;M~A;;.;R,;,cH;.;..;,,;19;;,;;8;.;.4_
BALLY MIDWAY
* *
MS. PAC-MAN
FILTER PCB CAUTION
POWER SUPPLY BURNT PINS MOO
BY DAVID OERMAN, KANE AMUSEMENT CO., PETAL, MS
B
ally Midway has a new version of Ms.
Pac-Man out that conforms to F.C.C.
rules Part 15 for a Class A computing device.
There are a few changes but the book, how-
ever, did not get changed.
Of course there is an RFI sh ield, and the
Ms. Pac Aux Board is inside it with the Main
Board. If you must pull the main board, don't
forget to pull the aux board out with it or you
will mess up the 40-pin jumper cable.
The most obvious change is the Power
Supply Chassis bolted to the bottom of the
game. It appears to be the same as used in
Ga/aga. It supplies filtered DC to both the +5v
and +12v rectifiers, filters and regulators on
the main board.
The F.C.C. filter board has also been
changed. The coils have been replaced by
Ferrite Beads. Most importantly pins C, 3, D,
and4 are all shorted together. In older games,
without the power supply chassis, pins C and
3 are one side of 7 volts AC center-tapped and
pins D and 4 are the other. If you plug a new
F.C.C. filter board into an older game, fuses
will blow!
Despite the nice new power supply, we
are left with the same old burning pins on the
main board edge connector and filter board
edge connector. Part of the problem is new-
pins 4, C and D are unused on the wiring
harness. Bally Midway must have expected
pin 3 by itself todothejobthat pins 3, C, 4 and
D could not do in the old Ms. Pac - that is
supply the boards with power without burning
up! I found an old edge connector and removed
3 pins with about 2" of heavy wire and inserted
them into pin holes C, 4 and D of the wiring
harness. I then cut the red wire going to pin 3
2" from the connector and soldered and taped
all 5 wires together. Now +DC enters the filter
board ,on all 4 pins instead of just one.
Pins 4 and D on the main board were
burned and the cause turned out to be D7
and D8, the +5v rectifier. When the game is
first turned on, one of the two diodes will start
conducting before the other. When it does,
the bias is removed from the other so the
other never turns on. This action prevents
either pins 3 and C or 4 and D from carrying
their fair share of the load. The cure is simple
- solder the "plates" of D7 and D8 together
with a piece of wire. If you ever need to plug
the board into an older game, just clip the
wire.
FREE CATALOG
OF HARD TO FIND PRECISION TOOLS
A
new catalog of precision tools and
computer and telecommunication
equipment is offered free by Jensen Tools
Inc.
1 llustrated in full color, the 80-page catalog
contains more than 1,000 tools of interest to
field eng ineers, techn icians, computer and
telecommunication service persons, and
electronic hobbyists.
Major categories covered are: test equip-
ment, micro-tools, soldering equipment,
tweezers, screwdrivers, cutters, drafting
supplies, power tools, computer accessories,
circuit board equipment and miscellaneous.
Also included are many new products from
Jensen plus page after page of service kits
and tool cases for electronic specialists and
technicians.
To obtain a free copy, write Jensen Tools
Inc., 7815 S. 46th Street, Phoenix, AZ85040,
or call (602) 968-6231.
ELECTROHOME AND WICO
FORM MARKETING/DISTRIBUTION PARTNERSHIP
E
lectrohome Electronics, Inc., Morris-
town, TN, and WICO Corporation, have
entered into a joint venture for the marketing
and distribution of Electrohome video display
monitors and parts, according to an announce-
ment by J.J. Malloy, vice president of U.S.
operations for Electrohome Electronics, Inc.
WICO Corp., of Niles, Illinois, the world's
leading designer, manufacturer and distri-
butor of parts and accessories for the coin-
operated amusement industry, will become
the master distributor to accounts connected
with the coin-operated industry in the United
States and Puerto Rico.
As master distributor, WICO will also provide
marketing and sales support for the entire
current Electrohome Electronics, Inc., line as
well as fu t ure product development.
"This business partnership will better
enable our company to service current and
prospective customers via WICO's marketing
expertise and extensive distribution system,"
said Malloy.
Electrohome Electronics, Inc. products,
used primarily by the video game manufactur-
ing industry, include 19" vertical/horizontal
monitors, 13" monitors, N.T.S.C. boards, 13"
I.G.T.s, Retrofit monitors and the X-Y Sega
monitor conversion.
According to WICO President Gordon
Goranson, "the purpose of the agreement is
to allow WICO to better service the industry
within this product category."
WICO will maintain stock of Electrohome
Electronics, Inc. products at the main ware-
house as well as regional distribution centers
in California, New Jersey, Georgia, Nevada
and Texas. An IBM 4341 on-line computer
system links all distribution centers to provide
WICO with immediate access to inventory
levels, product data and delivery times.
For further information about Electrohome
Electronics, Inc. products or other replace-
ment parts, contact your distributor or WICO
Corporation, 6400 W. Gross Point Road, Niles,
Illinois, 60648.
To call toll free, dial 1·800-323-4614.