Play Meter

Issue: 1977 April 22 - Vol 3 Num 8

Volume 3/No.B
April 22, 1977
Staff
Publisher and Editor:
Ralph C. Lally II
Managing Editor:
RichardS . Dietrich
International Editor:
David Snook,
Editor, Coin Slot
Technical Editor:
Robin Min near
Correspondents :
Roger C. Sharpe
DickWelu
Mary Claire Blakeman
J .W . Sedlak
RandvFromm
Art Direction :
Meyer Alewitz
Typography :
Skybird Typography
Circulation Manager:
Carolyn Desmond
Advertising Representatives :
Ralph C. Lally II
Carolyn Desmond
Advertising Production :
Don Randon
European Representative :
Esmay Leslie
Coin Industry PLAY METER, April 8,
1977. Volume 3, Number7 . Copyright
1977 by Skybird Publishing Company.
Full editions of Coin Industry Play
Meter are published monthly, the first
Friday of the month. The Update news
edition is published monthly, the third
Friday of the month. Publishing
offices : 4136 Washington Ave., P.O.
Box 14270, New Orleans, La. 70184.
Tel. 504 / 827-0320. Subscription rates :
U.S . and Canada - $25; Europe and
Japan - $45; elsewhere - $50 . One
order multiple subscriptions: 2-9, $20
each ; 10-24, $17 each ; 25 or more, $15
each . Advertising rates available on
request . No part of this magazine may
be preproduced without express
permission . The editors are not
responsible for unsolicited manu-
scripts . Application to mail at seco~d
class postage rates is pending at New
Orleans, La . Postmaster: Send form
3579 to Play Meter, P.O. Box 24170,
New Orleans, La. 70184.
member
2
amusement machines but indicated
that that would not change the
association's "long-standing com-
mitment to represent exclusively the
merchandise vending and manual
foodservice interest of its member-
ship:· NAMA also invited AMOA to
move with it out of Chicago.
Listed as reasons for continuing
to hold the AMOA Exhibition and
Trade Shows in Chicago were the
success, year after year, of the
Chicago show; the favorable loca-
tion of Chicago as a transportation
center to both foreign and U.S.
visitors; and the wide range of
facilities offered by the city in terms
of housing, accomodations, res-
taurants and entertainment. Also
noted was the fact that AMOA trade
shows have become identified with
Chicago "as the mecca for games
and music people from around the
world."
In accordance with its long-stand-
ing policy to arrange show dates
Sherwood Joins
Cinematronics
Jim Pierce, president of Cinema-
tronics, Inc., El Cajon, Cal., has
announced the appointment of Bob
Sherwood to the post of director of
marketing, effective immediately.
Sherwood formally held positions
with Chicago Coin as director of
international sales, assistant to the
president and most recently, direc-
tor of marketing. His service with
ChiCoin covered an eight year span .
In discussing his appointment,
Sherwood stated, "I am very
excited and pleased to be joining a
firm as progressive as Cinematron-
ics. They are fortunate to have one
of the finest engineering staffs in the
industry as evidenced by the line of
new arcade pieces, the first to be
released April," Sherwood added.
According to Pierce, Sherwood is
presently establishing a worldwide
network of distributors.
Pierce
further stated, "We are extremely
pleased to have a man of Bob's
caliber and experience joining our
team here at Cinematronics and
look forward to utilizing his talents
for our continued growth."
Sherwood will soon be relocating
to the El Cajon area with his wife,
Chris, and their four children.
current with those of NAMA when
that show is scheduled for Chicago,
the Board announced that the 1979
Exposition and Trade Show will be
held October 26-28. The NAMA
show is-scheduled for October 25-28.
in 1979.
The AMOA further issued an
invitation to NAMA "to hold its
annual shows in Chicago and to
work with the AMOA to establish
concurrent dates whenever possible
for the convenience of the whole
industry."
In other business, the Board of
Directors voted to hold the line on
exposition fees, both for registration
and exhibition, and , at least for
1977, to continue the no charge
policy for special events. It decided
to return the Regional Seminar to
Chicago, despite the success of the
Denver seminar, again because of
Chicago's convenience to travellers.
The mid -year board meeting for
1978 was set for Scottsdale, Ariz.
Calendar
May12-15
Music & Amusement Association
(NYC). convention and trade show.
Stevensville Country Club, Swan
Lake, New York.
May 20-22
Music Operators of Minnesota,
convention and trade show. Holiday
Inn - Downtown, Minneapolis, Mn.
June10-12
Colorado Coin Industries, annual
meeting. Holiday Inn, Glenwood
Springs, Colorado.
June 16-18
Illinois Coin Machine Operators
Association, annual convention.
Hospitality Motor Inn, Earth City
(St. Louis) , Missouri.
July17-19
Music Operators of Texas, annual
convention. St. Anthony's Hotel,
San Antonio, Texas.
July 22-23
Montana Coin Machine Operators
Association, annual convention.
Outlaw Inn, Kalispell , Montana.
Servicing remotely controlled wa ll
games can be a harrowing experi-
ence for a field mechanic with
limited electronics background . Be-
cause the system includes a trans-
mitter, a receiver and a logic system
(with its associated drivers and
display units), fault diagnoses can
often be a painstaking process of
trial and error. Fortunately there are
quite a few "tricks" to diagnosing
and repairing the little devils, so let's
take a look at the system and how to
troubleshoot it.
The majority of wall game prob-
lems are in the transmitter box. The
box is subject to great abuse at the
hands of players, and failure can
often be attributed to a fumbled
lateral across the back bar. The
shock from the drop can break the
crystal, and so the transmitter fails.
Crystals are a major replacement
item for the transmitter. (Batteries
and push button switches are also
high failure items but their diagnosis
is simple, and I'll say no more than
to keep them on hand at all times for
field service.)
One frequent field problem lies in
determining if the transmitter is
working properly. As a result of this
many servicemen have been haunt-
ing Radio Shack for C.B. goodies
like field strength meters, crystal
checkers , and the like . There is,
however, a highly simplified test for
the transmitter that you may already
be equipped to perform .
Through the miracle of Harmonic
Radiation , the transmission from the
" box" can be picked up on the high
end of your standard FM radio! Just
tune in around 108 MHz and, if
transmitter is functioning properly,
you'll here a tone modulated signal.
This is possible because the funda-
mental frequency of the transmitter
is approximately 27M Hz . This gives
it a fourth harmonic frequency of
(27 x 4 = ) 108 MHz. (See box .)
Since many vehicles are equipped
with combination AM -FM radios,
you may already have a mobile test
station that can give you positive
results without a penny of invest-
ment.
It is important to note that the
transmitter radiates a tone modu-
lated signal. In this respect, the FM
radio performs a function more
valuable than all those C.B. gad-
gets . The radio allows you to
actually hear what is coming from
the transmitter and so you can
instantly verify the presence of the
tone and its frequency. (Transmitter
frequency adjustment will be cov-
ered in Part II of this series. Watch
for it in next month's Update!)
WHAT IS A HARMONIC?
Harmonics occur in nature when-
ever oscillation takes place. Simply
stated, a harmonic has a frequency
that is an integral multiple of its
fundamental frequency. The organ-
ist, who might be playing the
fundamental note "A" (440 cycles
per second), can also bring in a
second harmonic (880 cycles per
second) or a third harmonic (1320
cycles per second) to enrich the
total sound of the note being
played .
We can make use of harmonic
radiation to receive the 27 MHz
-being transmitted by the "box ." A
standard broadcast FM radio is all
that is required to pick up the fourth
harmonic , as shown below.
FUNDAMENTAL FREQUENCY
27 MHz
SECOND HARMONIC
54MHz
THIRD HARMONIC
81 MHz
FOURTH HARMONIC
108 MHz
The tone is the "key" that
unlocks a circuit in the receiver
board . This allows a hi or lo signal to
pass to the logic circuits of the
game . If the tone is missing or
considerably off frequency, the
game will work erratically or not at
all. In Gremlin's Playball game, for
example, preswinging faults can be
traced to a bad switch, bad
batteries, and / or lack of audio
modulation .
Loss of the modulating signal can
almost invariably be traced to a
broken wire on the audio coil. (See
Figure 2. ) This can be easily
checked with an OHM meter which
should show 90 OHMS between
test point A and test point B, and
130 OHMS between test point A
and test point C. A broken coil can
be repaired if you can find the end of
the wire and perform micro-surgery
on it. The break usually occurs at a
post where vibration has broken the
connection .
Part II of this series will include a
step by step system for field
diagnoses and repair of wall game
transmitters, all centered around the
use of your FM radio . Tune in next
month!
~
Test Point B
Test Point C
~
L3
(antenna)
I
Test Point A
(
xtal ]
C9
,~----~-,-g-u_r_e_2_:_S_t_n_g-le--to_n_e __ /_2 __ 7_M __ H_z_t_r_an_s_m--iu--er-.------~

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