Star Tech Journal

June 1985 < 3) *********************************************************
be given a fair return
for their ■oney. The
i ■portant thing to re1eml:ier
here, is that different games
are percentaged differently.
As with all Stern games
there are a few problems.
Replace the flipper assemblys
with new Wico assemblies. It
would also be advisable to
replace the slingshots with
Wico's. The general
illu■ ination bus should be
wired directly fr011 the Power
Supply board to seperate fuse
holders for the Playfield and
Backbox bulbs. The
power/ground connector plugs
will always burn. Use the
titeak /~ coil for the upper
playfield.
■ust
BOOT
****
BA.LY/STERN DISPLAYS by
Erwin Boot, Aut0111atic Music
Co., Tas■ania, Australia.
How often have you replaced
a display glass on a Bally or
Stern pinball because the
display shOMed those 1ottley
dots and had lost a seg1ent
or two on a particular digit
because of burn out? Often,
right? "Yeah well, the
display is an old one so it's
to be expected that it will
eventually burn out" was
probably the thought in your
■ ind at the time.
The netiis is that there is
every chance that the burn
out was caused prematurely
and that your new glass is
going the way of all flesh at
this very IIIOlllent, because in
case of a break down of 1 or
2 transistors on the Voltage
Regulator/Solenoid Driver
board, the high voltage going
to the 5 displays is
225--230vdc instead of 190vdc.
Because of the circuit
configuration on Bally/Stern
Voltage Regulator/Solenoid
Driver boards, if 023 c,r 1222
goes short circuit, then
al ■ost the full 230vdc which
is supPoSed to be chopped
back to 190vdc 1 goes to the
displays. You don't notice
the fault, because all the 5
displays are still alive and
still show correct digits and
seg11ents.
I bought a secondhand Bally
pinball and in the shop I
noticed that the 4th player
display had 3 "blotches" ir,
the glass, even though in
this case they werer, 1 t too
bad, and that display was
still usable. However, I
decided to check the supposed
190vdc which goes to the
displays and is measured at
TP2 on either the VR/SD board
or on the displays (also
TP2l. Lo and behold, skyhigh
at 22Svdc! The trirapc,t had r,c,
effect.
1 grabbed the workshop
"test• < ! l board arid fitted
it and exactly the sa111e
problea, viz. unregulated
22Svdc. On the original, the
fault was a dead short G23
(00440 1 Wico 121-3753). On
the "test" board, not or,ly
was 023 dead, but so was 022
(also a 004401.
I've rarely had occasion to
have to check ■Y display
voltages before, because if
the displays are alive, one
assuES that they're all
clear. However, here I had a
2 out of 2 failure rate.
I've"'°" ir,stituted a 3
■onthly C011puter slotted
check of this voltage on all
■achines. In the meantime, I
would urge all Bally/Stern
operators to religiously
check this voltage on all
■achines which co11e through
the shop or lilhich show the
" ■ottley" display and despite
the various procedures ir, the
Bally handbook, suspect G23
and G22 first. Usually you
will also find that R51 (22k
oh ■ resistor, 1/2 watt) is
discoloured.
BATJ:STJ:C
****
Board Repair: like it or
Not by John Batistic, Univid
Test Syste■s, Cleveland, OH.
In the past we have all
learned to depend on the
distributors and the
111anufacturers to assist us
with our service funct ions.
Well, this period is comir,g
to an end.
If you have to depend or,
■anufacturers for assistarree
today you're in big trouble.
Factory staffing levels are
either down to the bone or on
their way there. Even the Big
Boys are laying off people ir,
droves (or going into Chapter
11), Factory service
depart ■ents are one of the
first items to be cut freim a
■anufacturer's budget. No
profits to be made there.
Fr011 a distributor
standpoint, the good service
shoP5 are up to their ears ir1
work. 60 there and you'll
have to Kait your turn. Also,
a lot of distributors are
closing their branch offices
and leaving a lot of
operators stranded. It's
happening all over.
It's time for the operator
to learn to stand o,, his owr,
feet. Whether we like it or
not, our industry is forcing
us in this direction. We are
on our 0111n ■ore aYl this is especially true in
the service area. Toll free
service n1111bers are
disappearing. A lot of times
we don't get the answers we
need even if they are still
there.
And llhat about the kits?
Conversion kits will probably
save all of our skins in the
long run. In 111any areas of
the world, there is no
dedicated game market ... only
software. But unless you've
got a Watts Line to Japan,
you won't be getting much
help fra11 the manufacturers.
Wakari ■as ka? It is hard to
service a game with Just a
list of the pin assign111ents
for the edge connector.
You can't fight the tides
of change, but is there
anything that we cari do to
help ourselves? Is there a
way to stay in step with the
industry as it heads in the
direction it ■ ust take for
it's own survival?
The only reasonable answer
for an operator (or a
distributor) is independence?
We ■ ust become more
independent if we are going
to survive the currer,t trend.
We all ■ust finally face the
fact that all of the
"High-Tech" is not going to
vanish, it is only goirig to
get ■ore co■plicated. We have
to prepare ourselves to cope
with the service problems of
today so that we will still
be around tOflOrrow!
We ■ ust become more
independent in many ways, but
1'11 here to talk about board
repair. How often have you
had to send boards out for
repair only to find the board
had no problem. When that
happens, the board cOMes back
(with a bill) and you still
have the proble111. The garae
doesn't work.
If you have not begun to
repair your own boards, ther,
it's ti11e to start. Repairing
boards is like anything else
that is new. You ■ust begin
s011ellhere. None of us was
born with an oscilloscope irr
our hand. The best
STAR*TECH Journa 1
technicians in the world had
a point in life when they
knew nothing about
electronics.
It will cost 1110ney.
Soaetimes we have to spend a
little money to 1ake mor,ey.
If you're an operator (or a
technician) and you see a
long-tera future for yourself
in this industry, ther, it is
time to invest in a good
■ulti--t1eter and possibly an
oscilloscope. You'll also
need a test fixture. I
recon!nd the UNIVID 1000. We
designed it to test the
boards of Just about any
color raster scan ga11e there
is ... including kits. There
isn't another fixture on the
■arket that can aake that
clai ■. We built it tough for
field use, and we are pledged
to ■ake it C011patible with
new gaaes as they c011e out.
Enough said.
The UNIVID 1000, combined
with an oscilloscope, a
1ulti--t1eter and the will to
learn can ■ake you
independent. The only other
ingredient necessary is ti ■e.
In tiae you can be repairing
your own boards (and saving
yourself a lot of 1110neyl. If
nothing else, you'll learn
how to properly diagnose
proble■s.
■uch
So
for the soft and
fuzzy part of this colU11n. In
future issues of Star Tech
Journal, I intend to share
so■e thoughts with you about
how we can all improve our
service both in the field and
in the shop. We'll get into
so■e real .eat-and-potatoes
issues in board
trouble-shooting and repair.
These principles are
universal and are applicable
to Just about any PC board.
So, whip out your sche111atic
diagrus, fasten your seat
belts, and welcOIIE! to the
world of board repair.
MURPHY
****
is ever a
failure --it can
always serve as a negative
example.
No
experi ■ent
co■plete
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