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
