Star Tech Journal

August
1985 (3)
•••**••••••••••••••••••••••••••••••••••••••••••••••••••
long button with a thins.itch bracket
(Wico 115-98181). Using a new piece of
NOOd aakes plugging holes easier. Also,
with 112• NOOd you can drill one hole
1- 1/8• for your button.
Using 3/4• NOOd, you can't always use
as.itch bracket. Here yours.itch will
11011nt directly to the NOOd. To aount
any buttons, drill froa the top with a
1-1/8• hole saw about halfway, 3/8•
deep. Then go the rest of the way with
a 3/4• butterfly bit. You can then
aount the button with Just a Pfl. nut
and no washers needed.
On the sheet aetal and NOOd panel
type, I also cut out for the Joystick
using a sabre saw so the Joystick
•itch holar is flush with the aetal.
This wi 11 be IION! secure and look ■uch
better.
TI£
EASY PART
Once everything is 11011nted, it's all
d If the wiring harness is long enough, I
si■ply cut enough for the length of the
control panel plus J• to 4• extra, to
wire the panel. First, connect a ground
wire to one side of all s.itches. Then,
using the edge connector pin-out,
solder the rest of the wires to the
appropriate s.itches; up, lbm, left,
right, 1 and 2 player start, kick,
Ju■P, fire, etc.
All that's left, is to install 2
Molex or AMP connectors, ■aking sure
the wires froa the logic board coincide
with the pins going to control panel.
Tie it all up with plastic tie-wraps
and that's it.
Well, next ti■e •' 11 do coin doors,
and so■e tips on ga■e cos■etics, too.
************
ERICKSON
114 TI£ SERVICE TRAIL ...
by Todd Erickson
Su.it A■useaent
St. Paul, ~
NISSLE llJIIAND Cllf.'ERSI~
With l"9CeTlt conversions going into
Atari's NISSLE aJIIAND, there has been
Pl"Obll!ll!i with voltage drops resetting
the ga■e , The cure is very si ■ple. With
the ~itional voltage plugs supplied
by Atari with the ga■e, the aachine can
be changed to a 95 volt unit. Check the
5 volts after this change-over to be
1111"1! it is correctly within tolerance.
~ID'S DART SAIES
Danger!!! These people have built
ttaselves into the replace■ent parts
business. The plug froa the ■e11brane
target ■ust be unhooked to service the
unit. Unf•iliar service technicians
can usily ■iss the warning in a dark
bar. Ar.chnid should receive an award
in poor design for this feature.
NINTENDO SYSTEM CCIIENTS
lllen the VS syste■ was first
released, the a■ount of software was
li ■ ited. BASEM..l was excellent last
siaer and this. Over the winter,
hoNever, there was a lack of good
ga■es, PINRL was Just alright at
best.
In the lut f11t ■onths, though, they
released EXCITEBIKE, ltl6ANS ALLEY and
Dlll< KM. All these are excellent .
ga■es, (The Dlll< KM, I feel, will be
a stronger Fall ga■e,) The de■and has
been so strong for these gues, that
they will be behind in shipping their
next gan for the next ■onth or two.
The guns have been getting such heavy
use, that the rubber has been Nearing
off the and of the barrel. I contacted
Nintendo and they will have a cure for
this shortly.
The large VS syste■ has been too wide
to mve into SOE locations. ""'n the
gaes are ■oved, I reco■■end re■oving
the control panels. They are easi 1Y
da■aged ■oving through doors. A
reaoveable front is in the works for
narrow doors.
With the VS syste11, • will be able
to ■ake good ■oneY with video again.
EVl!l'I the ■arginal ga11e will pay their
way with this syste■.
************
MURPHY
If a test installation functions
perfectly, all subsequent production
units will ■alfunction.
***********tr
B A T ::CST ::C C
INPUT PROBl.9IS
by John Batistic
Univid last Syste■s
Clwwland, Clf
Ont of the ■ost COMOn proble■s with
video ga■e logic boards is a proble■
with inputs. laputs are all the signals
that tell the gaa what to do. For
exaple; coin, start, fire, ■ove right,
ate.
We have all encountll"9d proble■s with
inputs and this is a good place to
begin our Journey into board repair.
Input probl ... are one of the easiest
things to repair and if you
IUCCllsfully repair anything on your
logic board, you will be building the
confidence you will need to venture
cnard to ■ore coaplicated proble■s.
I DENT IF ICATIIJ4
The first step is identification of
the exact ■alfunction. For our pur~,
• will say our board will not ■ove the
character on the screen to the right.
We have tested the ga■e and concluded
that tha Pl"Oblt■ is not the JOYSt ick or
STAR*TECH Jourr,al
the •iring. We have re■oved the board
froa the ga■e, plugged it into our test
fixture on our bench and sure enough,
the proble■ still exists. It is now
ti• to do so■ething about it.
PIN-OOTS
Look at the sche■atic and locate the
pin on the edge connector that is
■arked • ■ove right•. Probe at the pin
with a logic probe, ■eter or
oscilloscope. You should have a
nor■ally high signal that goes low when
you mve the Joystick to the right.
This aans you should ■easure around +5
volts DC and it should go to 8 volts.
Plll~ RESISTORS
You ■ay or ■ay not have the correct
signals Pl"ISlnt at the edge pin. The
signal ■ay be floating or it aay be low
all the ti•. A floating signal is one
that is rwither high nor low but
~ in bet.en. Floating or low
si1nals are ca.on and are usually
caUSld by a bid pull-up resistor, A
pull-up l"ftistor will either be part of
a resistor pack or a single resistor.
It wi 11 be connected to +5 vol ts on one
Ind and the input signal on the other.
It's function is to keep the input
signal at a nor■ally high state and to
Pl"ftlftt a dNd short when the signal is
trought to ground,
You can check the pull-up resistor by
disc:omecting the lHd froa the input
signal and probing on the disconnected
1 ... If the resistor is good, you
should have the high signal, You ■ay
also check the resistor with an oh■
■eter. If in doubt, change the
l"ftistor.
NJISE CA~ITORS
The next thing to check is the
capacitor in the circuit. The capacitor
will usually ha comected to the input
signal on one end and ground on the
other. It's purpose is to de-bounce the
input signal, A shortld or leaky
capacitor will also ca1111 a low or
floating signal. To quickly check the
capacitor, siaply cut and lift one end
of it and chick the input signal. The
signal should go high if the capacitor
is bid and should then be replaced.
INTEBRATED CIRCUITS
Once you have reached the point where
the pull-up resistor and the capacitor
haw bNn verified, you will be looking
at an IC chip, The chip will be
transferring the input signal onto the
Data Buss. There is no easy way to
check tha output of the chip so you
should swap it for a known good one.
WRAP UP
all input proble■s should be
solved by this ti■e. You should try
repairing one as soon as you can. This
will start to get you on the track and
build your confidence. Think of our
sc:hl!llatics u your road ■ap and follow
the signals like a high..ay. You ■ay
Al ■ost
···································································~·~·································