Star Tech Journal

STAR*TECH Journal
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the aain Audio/Regulator asseMbly which
is located on the hinged backdoor below
the logic boards. This aux +5vdc supply
has been reparted to be failing in
significant nu11bers. No sche111atic is
available for it (says Atari) yet.
The aain COIIP()nents are a Ul723 IC
regulator, a pass transistor and a
sense transistor. The part numbers on
the transistors are r10t readily
cross-referenced.
If unable to troubleshoot or find
suitable replaceaents for defective
parts, the entire unit can be replaced
with a switching type power supply.
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Gue: Bally Midway 6Al.AGA
1111111111111111111111111
Tech: Sall Cross, Godwir1 Distributing,
North Little Rock, AR.
SubJect: Logic Board Dip Switches.
Sy1ptoa: Galle resets Just when it is
about to finish its setup routine.
Solution: Switch 17 on the dipswitch
pack at 6J on the CPU board may have
becolle swithed "on•. This switch must
be in the "off" position for the game
to coapletely set up,
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Galle: Pretlier ELDORADO, ICE FEVER
111111111111111111111111111111111
Tech: Sa Cross, Godwin Distributing,
North Little Rock, AR.
Sy■ptoa: Displays blank out.
Possible Cause: Cold solder Joints on
the fl()llll!r supply section, particularly
01.
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Gue: Bally Midttay T~
11111111111111111111111
Tech: Saa Cross, Godwin Distributing,
North Little Rock, AR.
Sy■ptoa: Logic lock-up (1110n't resetl.
Possible Cause: Reset circuit on
PoNl!r board has becoae defective,
holding the reset line 10111.
Quick Cure: Cut the wire which goes
to pin 17 of the PQNer harness
connector on the middle CPU board.
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BAT::CSTJ:C
DIIBIISIS1 Tl£ FIRST STEP by John
Batistic, Univid Test Systems,
Cleveland, Iii.
The ultiaate goal for anyone involved
in service is a piece of equipment that
is in fine working condition, on
location and accepting quarters. When a
piece goes dONn the quarters stop. This
aakes it i1portant to get the piece up
and running as quickly as possible.
lllen veiNed fro■ this angle, it is
easy to see the i ■portance of quick,
accurate diagnosis. A sound approach to
troubleshooting is required. Orie must
take the time to think before actir,g.
This can save much ■ore t i111e ir, the
long run and aggravation in the short
run. Never assume anything. Observe the
proble■ until satisfied err0ugh that an
accurate description of the symptOIII can
be reached.
NoN, take the time to think it over.
lllat could possbily cause the problem?
Could the PQNer supply be at fault?
Make a few checks of voltage. Is the
voltage present on the logic boards?
Proper voltage must be reaching all
logic boards! Voltage should be checked
as part of the correct routine, If the
voltage is too high or too low a
proble■ is bound to occur.
Wiring is an integral part of every
piece of equiPIIE!nt. The wiring should
alMays be checked. Connections should
be observed and checked with an
oh.-.eter if suspicious. Check suspected
connections with an oh■-meter.
After going through a preliminary
troubleshooting routine the signs start
pointing to the logic boards. If no
proble11s are found during initial
inspection the boards may indeed be the
culprit!
Now Nhat? The ■ost efficient way to
check the boards becoMes i ■portant al l
of a sudden. Another ga11e would be an
excellent May to check the boards. If
another game is not available, a test
fixture that can si■ulate another game
is required! Using this ■ethod can
quickly verify board condition. The
boards Nill either check good or bad.
If the boards checked bad, the ga111e
troubleshooting has reached a quick
stop and the board troubleshooting is
about to begin. I know that for a lot
of you this aeans sending the board out
but for those of you that like to save
soae ■oney it aeans using everythir,g at
your disposal to repair the board
yourself.
Once again, a routine should be
follOMed. First, physically inspect the
board. Look for obvious things like
burned COIIPonents or bent pins. Many
ti■es it could be very siaple to find
the proble■ using this method.
Next, PONer the board up on your
tester. Observe anything you can on the
display. Identify the proble■
accurately, Think about anything that
could possibly cause the proble■. Refer
to sche■atics to identify the circuits
involved.
The direction that ■ust be taken once
this point is reached will differ
greatly depending on the problem at
hand. The board 11ay have a simple input
proble■ or it 11ay be totally dead. The
actions that ■ust take place from this
point will vary, aaking it impossible
to explain each one in detail.
In following issues I will take one
proble■ at a time in order to devote
the proper attention to each. Starting
with the si ■ple problems, I will work
tCMards explaining the more complex.
Eventually, ■ost of the C011110n problems
July 1985 (2)
encountered Mith the logic boards will
be addressed.
Until next ti ■e, remember to take the
tiae to think out things before you
act. This si ■ ple rule can save yc,u much
tiae and we know that time equals
■oney!
**********~"'t(
ENN::CS
Convlrsion Tips by Ji ■ Ennis, Ji11
Ennis Video Repair, Salisbury, MD.
With the trend leaning more towards
kits today rather than the cost of new
ga■es, a lot of operators are doing
conversions. I though I might have s0rte
"tips" on coverting the galleS since I
have been doing a nu■ ber of them since
Universal' s fl!R. DO!.
START-UP
One thing to reMe■ ber is the better
Job you do from the start will bring
you less problNS later on. A good
conversion takes a little time, but
it's worth it. A lot of ■y time is
spent on the cosaetics, because as all
operators should kn<>N 1 g.uie appeararree
is essential to incoae.
The ■ost i ■portant tip is to read the
directions. This is ti ■e well spent.
Try and understand what you' re about to
do before you Ju■ P into it. Pay
particular attention to the edge
connector pin-out diagram because I've
found in a lot of cases these are the
only directions you will get!
Most kits are basically the sanie. You
can break dOlffl the pin-outs into S
groups:
1. Power Supply
2, Monitor
3. Control Panel
~. Coin Door
S. Audio/Speaker
A good place to start is the PQNer
supply connections. But before we do
that, PQNer up the guie that you are
about to convert and verify you have a
NOrking gaae, PQNer supply and monitor.
PCMER SUPPLIES
Using a aeter, locate supply sources
+Svdc, +12vdc, logic ground and if
needed -Svdc. (A feM kits such as
Greyhound's VIDEO TRIVIA require the
-Svdc, And Just about all kits require
+Svdc and +12vdc.l The easiest way to
aake these connections is to use the
saae plugs that exist already on the
PQNer supply. You'll need replacement
pins. For Atari, Bally, Sega, etc.,
■ost are A■p or Molex type connectors.
(These pins and extraction tools are
available fro■ Wico,l On Williams'
ga■es you can use the 5aJle connector
and pin by reaoving the old wire and
insert the new. For Allp and Molex
connectors, cri ■P on the neM pin,
extract the old pin and insert the new
into its place. I've found this ■ethod
better than quick connects, butt
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