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Pinball Repair FAQ
Miscellaneous Pinball Fix-it Hints
by Johnathan Deitch
e-mail: litz@bellsouth.net
Ok guys ... here's a bunch of hints I've decided to ramble on about...
Realize the majority of my experience is Williams/Bally games (Whirlwind
to the present), so that's what I'm restricting myself to ...
Flippers
* Make sure the little piece of rubber that hits the EOS switch doesn't
wear through -- the metal post will cut a hole in the end of the EOS switch,
causing the flipper to stick. Replace the whole crank ... they don't cost
much.
* Replace your flipper sleeves, coil stops, and cranks frequently --
they're less expensive than new coils.
* Make sure the paper wrapper stays on the flipper (and any other) coil
as this will help keep the wires from getting damaged.
* Use the spacing guage in the spare parts bag to set the spacing between
the crank and the bottom of the bushing ... this will prevent binding
or excessive looseness (both of which will wear out the crank and sleeve).
* Replace the coil if a new sleeve won't slide easily into it -- this
means the coil has expanded from heat and will bind a crank sliding through
it.
Flipper circuits (WPC games)
* Check the optos on the flipper cabinet switches and U4/U6 on the fliptronic
II board (LM339s) as a weak or leaking LM339 (quad voltage comparator)
can cause a perfectly maintained flipper mechanism to behave like it hasn't
seen a wrench in five years. Optos can get dusty, so make sure they're
fairly dust free ... but don't use Freon (canned air) as it's cold enough
to damage the LED and photo transistor.
* Weak flippers that are mechanically fine ... replace the TIP36C darlington,
it's TIP102 driver, and the 2N4403 predriver for that flipper. A weak
TIP36C may leak slightly causing both warm coils and weak flips.
Switches
* Non-functional switch ... check the diode. Replace it. With a 1N4004.
* Check the column driver (ULN-2803) on the CPU board.
* Obviously, you should also check the wiring first ... make darn sure
the right wires are connected ... cross connected columns and rows can
cause all kinds of havoc.
* If it's a microswitch, they do go bad too ... listen carefully for
the "click" when the switch closes ... Lamps, flashers, and coils
* If wires and diodes and all are all ok (and the coil isn't burnt out)
you likely blew a driver transistor ... check the manual for location
and replace it. It'll be on the power driver board or (in the case of
the wide body games) possibly on an auxiliary driver board.
Care and feeding
* All pivoting points should be oiled, with the exception of flippers.
This means the hinged points on ball launchers, trough poppers, slingshots,
and similar mechanisms. Use 3-in-1 light machine oil. Never, ever, oil
the plunger of a coil. The graphite given off by the plunger sliding through
the coil sleeve is sufficient lubrication. Anything added will cause the
graphite to clump and become a gummy, gooey mess.
* Check your flipper and other coils every now and then ... replace any
worn sleeves and wipe down the shafts. Replace any coils that are binding.
* Clean your playfield *weekly*. Dirt and grime buildup are the #1 cause
of eventual failure of electrical and mechanical parts. Keeping the playfield
clean will keep the dirt out of switches, off lamps, etc ...
* Rotate your flipper rubbers when the tips get worn and use rubber cleaner
(RC-88 from Wildcat) on the playfield rubbers every time you clean the
playfield.
* Don't forget to clean the balls too, or simply replace them. New balls
are only $1.25 each or so. Scuffed balls will tear your playfield to pieces.
* Be sure to level the game left-right (use a carpenter's level on the
upper and lower parts of the playfield) as well as a 6.5 degree slope.
Best way to set the slope is to visit your distrubutor and purchase one
of those nifty slope bubbles Williams puts on their games ...
Playfield cleaning
* Diamondplate finishes are essentially sealed in plastic. I use Novus
plastic polish #2. Novus #2 is also good on mylar. Spread it on and buff
it in like car wax. Let dry, and buff off. Change cloth frequently to
get clean cloth on the playfield. Whatever you do, don't use Wildcat 125
on a Diamondplate (or other hardcoat) playfield. It will damage the acrylic
plastic hardcoat, ruining the playfield. CP-100 is okay, but be forewarned
that it will strip mylar off a playfield as easily and efficiently as
it strips off the dirt and grime !
* I also use a soft brush to brush all the bits of novus and cloth pieces
off the playfield -- just brush it down the drain at the bottom of the
playfield. It'll drop down to the bottom of the cabinet for easy cleanup.
* Check your light bulbs for cleaning ... under-playfield bulbs will
get very dirty from solenoid dust, etc. Wipe 'em clean and see how much
brighter your inlays get!
Adjustments
* not much here ... but note that slingshot switchs should be spaced
1/16" apart.
* Common light bulbs are 555 and 44, as well as 89 and 906 for flashlamps.
Twilight Zone use #86 lamps in the clock.
* All switch, lamp, and coil diodes are 1N4004, coil/flashlamp drivers
are TIP102's, hi-power coils are TIP102/TIP36C pairs. Each uses a 2N5401
predriver.
* Flipper power drivers are TIP102/TIP36C pairs, flipper holding drivers
are TIP102's. Each uses a 2N4403 predriver.
Caveats
* Never ever ever get RC-88 rubber cleaner on playfields ... it'll eat
through Diamondplate and strip paint right off. Never use any spray or
cleaner on cracked paint -- it'll seep under and the paint will flake
off. Wildcat #125 will cloud clear plastic ramps.
* Novus cleaner can also be used to clean playfield plastics (undersides
too), plastic ramps, backglass art, et al.
Anything I forgot?
All contents wriiten by and copyright by Jonathan Deitch, musjnd@panther.gsu.edu
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