Twilight Zone pinball Repair FAQ
By Jonathan Deitch
e-mail:
[email protected]
website:
http://personal.atl.bellsouth.net/atl/j/d/jdeitch/
January 8, 1996
Fix-It hints for your Twilight Zone Pinball
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Well, I've been thinking on this for a long time ... TZ owners, here's your
"fix-it" bible ...
Twilight Zone is one of the most complicated pinballs Williams/Bally [at
http://www.wms.com] has ever produced ... it's the only game that I know of
that (in its prototype form) used all 28 coil drivers, the entire lamp matrix
(64 lamps), the entire switch matrix (64 switches), all eight switches on an
auxiliary "9th" switch column (making it 72 total), and an entire 8-driver
auxiliary coil driver board (used for 7 coil drivers and the 9th switch
matrix column) ... plus all four flipper positions on the flipper board !
Added Together :
43 coil drivers (28 standard, 7 on the aux driver board, 8 on the
Fliptronic board)
72 switches (80 if you include the coin door buttons and coinswitches)
64 lamps
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First a disclaimer -- I will not take responsibility for ANY damage done to
your machine by anything I describe. What I describe are things I have
found work for me. I am an experienced pinball technician. They may or may
not work for you, depending on your experience level. If you do not feel
comfortable doing any fix or repair needed for your game, DON'T DO IT !
It's usually cheaper to hire someone to do it right than to hire someone to
_undo_ what you've done wrong and _then_ do it right.
So now that you're scared to death to lift that screwdriver ... :-)
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The Clock
TZ's clock is a wonderfully designed piece of mechanical engineering that
can actually tell _real_ time, if that option is enabled in the software.
Unfortunately, it has an achilles heel that can bring the whole mechanism
to a screeching halt -- heat !
See, the Clock was originally designed so the lamps were on the game's lamp
matrix ... for what reason I'm not sure, but probably to do some neato
strobing effects ... anyways, the designers ran out of available lamp slots
on the lamp matrix and the clock lamps were moved to the GI circuits (same
circuit as the "Twilight Zone" in the backbox, BTW) ...
When this was done, the diodes needed for the lamp matrix were replaced
with jumpers as they aren't needed for GI lamps.
(Special thanks to Uncle Willy
[at
http://www.wms.com/williams/willyworld.html] for this Information)
Unfortunately, the result is light bulbs that get VERY hot from the GI
circuit as they're on _all the time_ ... and this heat will almost certainly
destroy the optos in the upper parts of the clock as there is no
ventilation for the heat to escape through ! What's more, the pins that
connect the minutes opto board to the hours opto board get cooked by this
heat as well and delaminate, causing a very poor connection between the two
boards and spurious problems with the hours optos ...
The solution to this problem is to first replace the jumpers installed in
place of the lamp matrix diodes (D1-D4 on the minutes opto board) with
those diodes again. 1N4001 or 1N4004 diodes work fine. Direction doesn't
matter as GI power is AC, but the PCB is actually silkscreened for the
original diodes.
An additional nugget of info from Marc Howard is that you can install D2
and D3 in the _reverse_ of the silkscreening ... this will cause lamps one
and four to light on one half of the AC cycle and lamps 2 and 3 to light on
the opposite half of the AC cycle !
Second, you need to remove the clock guts from the clock casing and drill
ventilation holes in the clock casing. I usually put two in the back part
of the roof for the back part of the clock (so the hours optos can stay
cool) and two in the front part of the roof right over the light bulbs
(between the PCB and the clock face) so the light bulbs' heat can escape. I
also drill inlet vents on the lower parts of the sides in each section so
cool air can come in. Natural convection will take over to cool the clock
as the hot air rises, escapes, and cool air is drawn in to replace it.
You will also need to replace the pins between the PCB's if they are
visibly cooked (they'll look tarnished) and any optos that have been
damaged by the heat.
When you reassemble the clock, pay close attention to the instructions in
the manual -- it has very specific steps to follow for proper clock
alignment.
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The Gumball Machine
The Gumball Machine is, if possible, a cooler piece of engineering than the
clock. It's main point of failure is dirt. There is only one switch inside,
called "Geneva" that is used to detect one revolution of the mechanism. If
this switch gets too dirty, it can fail to make contact when closed causing
a failure. Other points of failure are on the opto pair at the entrance to
the Gumball (on the wire rail) ... Kevin and Keith once reported theirs
broke off the wire rail ... anyway, these are subject to quite a bit of
vibration and this can cause broken LED legs and failure. Lastly, the
gumball popper, like all ball poppers, is subject to dirt that can occlude
the opto's lens ... this will cause the game to think a ball is permanently
in the popper ...
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The Bridge Diverter
This is the thingy on the Right Ramp that 1) drops the ball into the left
spiral for you to bang into the Piano or 2) hurredly gets out of the way on
a Powerfield shot ...
It is connected via a pull wire directly to its coil, so if it doesn't go
down, it's usually due to a broken wire, a bad coil, or something hanging
the mechanism up ... assuming, of course, that the opto on the right ramp
is functional ...
What is _more_ common, however, are two problems :
* The ball bounces into and out of the carriage, and rolls waaaaaay back
to the right. The Diverter diverts and slams the ball (which is now
back to where it's supposed to be) SDTM when it pops back up. This is
fixed by adjusting the height of the middle of the wire rail -- the
leg that mounts onto the left post of the left ramp entrance is
supposed to be firmly screwed into place. It may need a washer or two
underneath it to shim it slightly upwards.
* The Diverter dumping the ball either out the side or up the spiral
loop ... this can be fixed with some very gentle bending of the
carriage ball guides to help the ball along the proper trajectory.
Lastly, the hinge pin (part # 02-4837) can get very worn over time, causing
a MAJOR wobble in the diverter carriage. This can cause both problems
listed above.
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The Powerfield
Most of the powerfield problems are electrical in nature, especially with
the magnets. The biggest thing to watch out for here is that two plugs on
the wiring harness are _IDENTICAL_. One goes to the optos, the other to the
magnets and flashlamps. Needless to say, plugging them up backwards will
put a 50vdc potential to your opto detectors and _fry them but good_.
Double check carefully before plugging this sucker back in ...
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The Flippers
TZ's flippers are as follows :
* Lower left/right : FL-15411 coils
* Upper left : FL-11753
* Upper right : FL-11722
I strongly suggest an outright replacement of: coil stops, coil sleeves,
crank/link assemblies, and the coil itself if the sleeve won't slide in and
out easily. The parts are inexpensive and replacing 'em is much easier than
trying to resurrect worn parts. Worn parts have fairly obvious flat spots
and/or mushrooming on the ends. You will also want to replace the return
spring if needed ...
Parts needed :
* Coil Stop (A-12111), Crank/Link (B-13882-R or L), Coil Sleeve
(03-7066-5), and if needed the return spring (10-364)
One other thing to watch out for the the EOS paw on the crank -- this is
the little arm that strikes the EOS switch blade. Normally there's a piece
of 1/4" heat shrink tubing here to prevent metal from rubbing on metal, but
on older flippers it has often rubbed off -- and the steel of the crank
will cut right through the copper of the EOS switch. So if you find your
old crank has worn through the heat shrink tubing, consider replacing the
EOS switch as well -- part # SW-1A-194.
I align flippers so the facing of the rubber is perfectly parallel with the
wall that feeds the flipper ... either the wall of the upper loops or the
wall of the return lanes. This may or may not work for you.
Oddly enough, TZ shipped with _red_ rubber ... the part # in the manual is
for _red_ rubber, but the name given in the manual is for _yellow_ rubber.
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Under-the-Playfield Mechanicals
Be on the lookout for three problems (other than the Piano & Camera scoops
coming loose) :
* The left wall of the Slot kickout loop can break loose. This usually
happens on games with no bracing on the Slot Greed target. This
requires replacement of the loop unless you can spot-weld the wall
back in place. If this isn't fixed, balls will not kickout reliably
and can kick out straight down the middle ! I brace replacement loops
with a screw fastened across the middle, just back from the kickout
edge. If it is located high enough (ie: just under the mounting
flanges) the ball will fly right under- neath when it is kicked.
* Speaking of the Slot Greed Target, this beast is not normally supposed
to collapse backwards ... instead it's supposed to send balls that hit
it straight down the middle ! It can be braced from the rear by
installing a slingshot hinge (part # A-5653) so the long part of the L
sticks out behind the target's backrest and the two screw holes on the
short part of the L are between the base of the slot greed target and
the lower target on the side bank. It fits right into place there
between the two target bases.
* Lastly, like the kicker in the bottom of Thing's box, some Slot
machine kickers have a tendency to crack right off the base of their
mounting brackets ... if you see cracks forming, order a new one ASAP !
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Errata
* Have you found your "Upper Right Flipper" flashlamp yet ?
o Hint : Look _under_ the plastic above the UR flipper ...
* If you are plagued by airballs that hit the righthand Powerfield sign,
make sure your flipper rubber is _above_ the bottom line on the flipper
paddles and that your Slot Greed target is properly supported.
Otherwise you are just inviting balls to mimick F-16's ...
* Check your Auto-launcher and Rocket kicker -- they are supposed to
have special kicker arms with _cupped_ kickers to help aiming ...
* If you have a White clock game and the post for the third magnet,
check your wiring harness -- likely all the wiring is there for you to
reinstall the third magnet and its opto plus the clock passage opto
and the second Autoplunger opto! You get no real benefit from doing
so, but it's kinda neat to own a "retro" TZ ...
* The game will recognize and use the third spiral magnet in "Spiral"
mode, but it ignores (completely) the clock passage opto. I'm not sure
if it does or doesn't use the second Autoplunger opto, but I've seen
ours put two balls in there ... whether due to trough switch problems
(which I just fixed) or that opto is unknown.
* Have you seen the roadmap under the Right Ramp yet ? If not, you need
to clean your ramp ... :-)
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That's all I can think of for now ... I'm sure I'm gonna get plenty of
corrections (I typed all this in off the top of my head) ...
