Play Meter

Issue: 1975 February - Vol 1 Num 3

"For n the spot repairs," adds Jim, "a pulser
probe is great. I t inject a spike manually or
automatically about each s cond, cha nging the
existing conditions on the IC ( integrated circuit)
chip to determine whether it is good or bad.
Art Freeman . director of training, omit Coin
perated Machine Institute of Technolog , 2115
Beverly Blvd .. Los Angel es has a brief case tool kit
for field repair. Upon opening hi brief case, it
revealed:
- I ng-n s pliers, wir tripp r ; cu tt e r; a et of
X elite 99-P -50 crewdriver-nut driver com pact
et: an ice pick: as orred lamps used in coin-
machines (44 s. 47's. et .), assorted nuts: bolts;
screw: an assortment of integrated circuits; transis-
tor and diode; a magnifying glas; mall (ac id )
bru h: and an Allen wr nch et. (Th ice pick i
used for prying up I ' . marking and scor ing
boards for hole, etc.)
Of cour e. the oldering iron go
wherever
Freeman. Tomei or an game technician goe .
Freeman and Tomei emphasized one difference
between electro-mechanica l game and video/so lid
state games i m re of a need on the latter to work
in a hop-laboratory atmo phere.
An oscilloscope is frequently needed to view
variou waveforms on video game and is a must
tool for video game technician. " I perso na lly
would not haul a 'scope' out on location," cautions
Tomei.
"External distraction are a real hindrance o n
location when attempting to locate problem on
video game ' he add. " Beside, " he joke " 1 say
a lot of bad word when 1 m diagnosing pro bl ems
and I pr fer the privacy of our shop's back room . '
Freeman agree, but i qui k t o add that an
operator can benefit by u ing ome of the ba ic
tool to determine when t
bring game from
location to hop for repair.
Atari, in conjunction with Kurz-Kasch I nc., an
e lectronics firm in Dayt on, Ohio, has d velop d
the n w LP 600 tv te t pr be to ena ble the
operat r to diagno e hi game. This instrument
will h ·Ip dctermin wheth r the problem i gener-
a ted from the computer board r the tv failing to
tra k the board' information.
Example: You have a loss of video. Ha s the logic
board failed? r i it the tv that failed?
The new LP 600 tv te t probe will enable you to
determine which as embl has failed. A imple
readout
tcm indicates "one ." "zero" or "pul 'e"
reading through color-coded visual electronic read-
o ut in the probe tip. Absence of logic levels is
indicatcd by all readout remaining" fE."
The probe is small enough to be carried in a shirt
pocket. Es entially, the logic prob knows more
about each logic family then technicians, reducing
an urgency for advanc ·d training before using the
pro be.
Here i how to connect the probe:
COMIT COIN MACHINE SCHOOL'S Art Freeman, seated,
shows one of his advance students, Ken Berian, of Los
Angeles, how to trouble shoot a video game logic board.
Note the oscilloscope in background.
First connect the red and black leads from the
probe to the computer boards +5VD a nd ground.
Second the tip of the probe i pl aced on the
appropriate pin :
Test function!
video·pin 2
video· pin ,
.
1
Type!
Television!
MGA·
Pin , .
Ground
Pin 2·
Video and sync
Pin 3·
Audio Motorola
Pin , .
Ground
Hitach i and Zenith
Pin 2·
Video and sync
Pin 4·
Audio
> •
2
If +.5v video level i pre ent. the red lamp of the
probe will illuminate.
(Please Turn Page)
13
5H[]P. ..
I f an video i pre 'ent at all
say, if the core IS
present, but not the net r the paddle
then
video i pre ent to the tv, but the problem is on
the computer board.
If the 5 micro ec. horizontal ynchronizing
pul e are pre ent from the I gic board, they will
o perate the tv sw e p ircuits and the white lamp of
tatives readil agree that it is possi ble to find 90
per cent of the po sib le printed circuit board
malfunctions without the following item, if an
game c mpanie desire a complcte arra of trouble
-shooting cquipment, they recommend:
probe and the tv can't be locked in horizontall ,
then the tv is bad.
Atari recommend u ing the Kurz-Kasch LP-520
probe for testing the audio output of computer
boards. Since the audio signal is a 5v logic signal,
the red lamp of th probe will illuminate when
audio i pre ent.
Atari will provide free video probes through
their customer servic' department in Los Gatos,
a liforn ia. The video probe is a very imple, but
u eful device, con i ·ting of two tc ·t c lips, a length
of rubber-coated test-lead wire and a 4.7K one-
fourth watt carbon resistor. Video probes may also
be assembled from standard components available
at all electronic supply hou es.
To u e the video probe, ana h one clip to the
negative (-) side of the 10 uf video coupli,ig
capacitor found ncar position 9 on the printed
circuit board and clip the other end to the desired
signal test points. The video probe allow ' the
desired signal to be displayed on the tv monitor
creen.
Alth ough even Atari customer 'crvice represen -
tative readi ly agree that it i possible to find 90 C
of the possible printed circuit board malfunction s
without the following item, if any game om -
panic ' desire a com plete arra of trouble- 'hooting
etluipment, they recommend:
- Hewl ett-Packard 10529A Logic omparator,
u ed to verify correct I operation. This device
lip onto in-circuit I ' and in tandy di pla y
any logic tate differen ,between the incircuit
test I and the reference I in the comparator.
Hew lett-Packard 10526T Logic Pulser, used to
stimulate in -circuit I ' 0 that the arc driven
to their opposite tate.
Textroni 465
cilloscope, previou sly men -
tioned. for viewing wavelength s.
C.A . ROBI NSON'S Jim Tomei uses a probe to determine
the condition of a logic board's chips. Tomei took
electronics in high school and additional courses during hi s
Army duty. After being discharged from the Army, he first
worked as a tv repairman in Chatsworth. I n addition to the
standard technician's tools, Tomei recommends including a
jeweler's screwdriver with a narrow or flat tip for prying
out pins in logic connectors.
14

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