2a. Before Turning the
Game On: Check the Fuses
Seems like such a
simple thing, yet many of us forget to do it. Before you even turn the
game on, check the fuses. Not only look for blown fuses, but
over-fused circuits. For example, is there a 25 amp fuse where there
should be a 10 amp? Save that 25 amp fuse for your car and put the
right fuse in!
There are at least three
fuses located near the front of the cabinet on any EM pinball. One
fuse for the solenoids, one for the playfield lights, and one for the
backbox lights. There may be more (depending on your game). Often
there are fuses located else where too. You'll have to hunt around for
them. There's usually a fuse for the the reset bank, and sometimes
under the playfield for certain features.
Testing Fuses: the
Right Way.
Don't depend on your eyes or sense of smell to check
fuses. A perfectly good looking fuse could be open, it happens all the
time. Fuses can go open because of age (fatique) too, and not just
from shorts or high current. Use your Digital Multi-Meter (DMM). First
remove the fuse from its holder, or remove just one end of the fuse
from the holder. This is important, and applies to Solid State games
too. Don't try and test the fuse installed! Set your DMM to
"continuity", put a lead on each end of the fuse, and buzz out those
fuses. No buzz means fuse is bad.
(Side Note: a "buzz" on
your meter means zero resistance. If you don't get a "buzz", either
the circuit is OPEN, or the resistance is 100 ohms or greater. If your
meter doesn't have a continuity function, just use the lowest
resistance setting. A good fuse will measure zero ohms.)
Fuse
Holders.
Often the fuse holders on EM games are tired and have
lost their "spring". This will cause a bad power connection. Symptoms
include missing all lights on the playfield or backbox, all coils
don't work, or a game that just won't power on. This is very common on
Bally games. Often you can bend the fuse holder tabs for a better
connection. Sometimes you'll break the tabs doing this. Keep a stock
of new fuse holders around and replace when needed. Also clean the
fuse holder. These can be so dirty, the fuse won't make contact to the
holder. Dirty fuse holders can also cause resistance, and the heat
generated can cause the fuse to open.
2b. Before Turning the
Game On: Plug Connectors
So you bought that
"new" (to you!) EM pinball, and it's time to set it up. Before you
plug those connectors in after bolting on the head, clean them! It
only takes a moment, and it removes the crud from a 25 year old (or
older!) connector. Though connector problems aren't real common,
cleaning is just a good idea.
A Gottlieb
Connector after a quick cleaning...
Before plugging the
connector in, take your 600 grit wet/dry sandpaper and sand the
circumference of the male side of each pin of the plug. This is the
area that the female plug bites in to. Wrap your sand paper around
each pin, and rotate a few times. They don't have to shine like a new
penny; just get the major crud off.
It's also a good idea to
clean the connectors that attach to the bottom panel of the game, and
the coin door connector. Gottlieb coin door connectors are especially
important: if this connector is not making good contact, often the
game will refuse to work!
2c. Before Turning the
Game On: Switch Contacts
A Word of
Caution...
When I first started getting into EM pinballs, a
well experienced repair friend stated, "if every switch
contact in the machine is clean and properely adjusted, your game will
work perfectly". I thought to myself, "I can clean and adjust
contacts and get this Nip-It working myself!" (Nip-It was my first EM
fixit project). Unfortunately, this statement is an
over-simplification of the truth.
I did clean and check
(and often adjusted) every contact on that Nip-It game. And in
reality, his advice did NOT work. I ended up with a game that worked
far worse than when I started. I created problems that weren't there
in the first place. This was mostly because I didn't have the
experience to tell when a switch really needed adjustment.
There is a moral to this
story: "if you're new to EM pinball, don't fix, clean or adjust
what isn't broken".
If you are experienced
in EM fixing, then fine, clean every contact and adjust as necessary.
I do this now that I have the experience, and it works quite well.
Before I even turn the game on, I clean and check most switch
contacts. BUT if you aren't experienced, please don't try this! You'll
only make your problems worse. Just follow along and do the bare
minimum amount of contact cleaning that I suggest.
Why Do Switch
Contacts Get Dirty?
Whenever a switch contact open or closes, a
small arc of electricity occurs. On high current solenoid circuits
like flippers and kicking rubber, this blue arc is quite large and can
easily be seen. This arc burns the switch contacts slightly, and
produces some black soot. Over time, the switch contacts can increase
in resistance from the contacts burning and the soot
produced.
To prevent this, switch
contacts are to be adjusted with a "wiping motion" that self-cleans
the contacts as they operate. But if a game is in storage for a period
of time, burnt contacts can oxidize. If a switch is mis-adjusted and
doesn't clean itself with a wiping motion, it too can fail. This is
why switch contacts need cleaned and perhaps adjusted.
Cleaning the
Contacts.
Dirty and mis-adjusted switch contacts are the major
cause of all EM pinball problems. Fixing your EM will require you to
clean and adjust some contact(s).
(Left)
Filing a relay switch in tight quarters.
(Right) Filing the
flipper EOS switch on a Gottlieb.
 
To clean contacts,
you'll need to use your Flexstone file or a small metal point file.
Just put the file between the two contacts to clean, and file them.
You will probably need to hold the two contacts together with your
fingers to get ample pressure to clean them. Don't hold them too tight
or you will distort and bend the leaf switch blades. The metal contact
pads should be shiny and clean when you are done.
Using needle
nose pliers to hold
two contacts together while filing
with a
flexstone on a Gottlieb
reset bank.
Often, especially on
relay switches, the adjacent leaf blades will be so close together
that you can't get ample pressure against the file to clean the
contacts (your fingers won't fit!). In this case, use a small screw
driver to put presure on one of the contacts. Sometimes manually
activating the relay with your hand helps apply pressure to the
contacts for filing.
Other times using your
fingers or a screwdriver to get pressure on the contact for filing
won't work. For example, on Gottlieb game feature and reset banks,
there just isn't enough room. Instead, you can use needle nose pliers.
Just gently hold the two contact together with the pliers and the
flexstone between them.
Most switch contacts
are made of silver. These contacts file fine with a flexstone. But the
contacts on the flipper button switches are made of tungsten. These
contacts will have to be filed with your small metal file, or removed
from the game and filed with a standard metal file. Tungsten contacts
will wear out a flexstone in short order; the flexstone just can't cut
them. Note that during the 1970's, Williams and Bally started using
tungsten contacts on pop bumper and kicking rubber switches
too.
Self-Cleaning
Contacts and Types of Switches.
All EM leaf switches have a
"wiping" action to them: the short blade contact is stationary, the
long blade moves and makes contact with the stationary contact. As it
makes contact, the switch will continue through it's stroke and wipe
itself on the stationary contact. This is known as a "self cleaning"
switch. For the self cleaning to work, the stationary blade must move
a bit in the entire switch motion. Of course this doesn't happen all
the time, but it should.
Shiny clean and
smooth
EOS contacts after filing.
With this in mind,
adjust any switch so it has this wiping motion. Normally Open
(NO) switches should have about a 1/16" distance between the contacts.
And as the two contacts touch, they should continue to touch and
"wipe" as the switch continues through its stroke.
Normally Closed
(NC) switches should be adjusted the same way: make sure as the switch
opens and closes, there is some wiping action. A 1/16" contact
distance when open is desirable in most cases.
Make/Break (M/B)
switches are the toughest to adjust. They have about the same amount
of travel as the normally open and normally closed switches, but have
two contacts to make and break and wipe clean. Adjust the best you
can!
Damping Switch
Blade.
On playfield switches, there is a third, shorter switch
blade sandwiched between the two contact blades. This damping blade
provides support to one of the contact blade, so the switch doesn't
"bounce". But sometimes these damping blades get bent and short out to
the other adjacent blade. Be aware of this. When you adjust a switch
with a damping blade, you must adjust both the short contact blade
and the damping blade together.
Note the
Damping Blade: this playfield switch has a third shorter
blade
between the contact blades to provide support. Make sure
these
damping blades don't short out against the adjacent blade. And
remember,
don't adjust the long blade. Adjust only just the short
blade, and the
damping blade (if the switch has one).
Adjusting
Switches.
Adjust the short (stationary) blade contact only (and
the damping blade if the switch has one). Put your contact adjuster on
the short blade (and the damping blade), and slide it down to the
bakelite insulator stack. Bend the blade here. The only time you will
ever have to adjust the long (moving) blade of a switch is if someone
before you mistakenly did this. Otherwise the moving blade of any
switch should never be adjusted.
Using a
contact adjuster to adjust the short blade of a switch.
Tighten the Stack
BEFORE you Adjust!
If a switch needs adjusting, you should
tighten the switch stack before you start. The switch stack consists
of the switch leaf blades, separated by bakelite insulators. These
insulators will dry out and shrink with time. This loosens the whole
switch stack and contributes to switch mis-adjustments. Also, if the
switch stack is not tight, the bakelite insulators can become damaged
with humidity. So before you actually adjust a switch, tighten the two
screws that hold the stack in place. Note: tighten the screw
closest to the switch contacts first.
Note the adjustment you
make to the switch stack will not be permanent forever. At some point
(could be many years!), the stacks will "loosen" again, and switches
will need re-adjusted. To determine if this is currently a problem,
try tightening a few differnt switch stack in the game. Are they
loose? If you found a few loose, keep this in mind. Since your sample
is loose, the whole game will probably need attention in this
area.
A Mis-Adjusted
Playfield Switch: Notice the damping blade in the middle
(which
dampens the upper contact) is shorting to the lower contact. Yet
the
contact pads are adjusted correctly. This is visually
deceiving.
Fish
Paper.
You ask, "what is fish paper?". Well that's the
insulating gray paper you see between switches, mostly in switch
stacks. It prevents one set of switch contacts from shorting against
another. Often this paper gets worn and damaged. This can cause
adjacent switches to short. Inspect the paper, and replace where
necessary.
Think BEFORE You
Adjust!
Let's repeat that: Think BEFORE You
Adjust!
If you are adjusting more than about 5% of all switches
on your EM pinball, you are probably doing something wrong! Stop now
before you make your troubles worse. Unless the game has been mangled,
adjusting more than 5 switches out of 100 is very unlikely. See the
above "Word of Caution"...
2d. Before Turning the
Game On: Score Reels
Think about it: what's
the most used (abused!) device on any EM pinball machine? The score
reels! (Note: if you have a 1950's game without score reels, skip to
the Stepper Units section.) They move for every
point scored, hundreds of times per game.
If your score reel
contact points are mis-adjusted, your game will never complete its
start-up sequence! This is definately the most common problem in EM
games. It's pretty easy to identify this problem too: you press the
"start" button on the coin door, but all you hear is the score motor
in the bottom of the cabinet "running". It never stops running, and
the game never comes close to starting.
The reason the score
motor is running is the game doesn't think the score reels are reset
to the zero position. This happens for a bunch of reasons, but usually
it's because the Zero position switch(es) are out of adjustment or
dirty (though sometimes it can be as simple as a wire fell off the
score reel solenoid, or the solenoid is dirty and
sticking).
Removing a Score
Reel.
Each score reel will have some easy mechanism to remove
it from the backbox. On most Gottliebs up to 1967, the "rat trap"
reels have a small "hairpin" that must be removed. On 1967 and later
Gottlieb "decagon" score reels, there's a nylon release tab. 1970's
Bally and Williams have small levers that are held to remove the score
reel. Whatever your game, there will be some mechanism that allows
easy removal of the score reels for service.
Checking for
Mechanical Problems.
With a reel removed, manually press the
coil plunger in and let go quickly to release it (you have to do this
quickly; if you let the plunger out slowly, there may not be enough
momentum to move the score reel to the next digit). Does the reel move
easily to the next digit? If not, you'll have to disassemble the
mechanism and clean the moving parts with alcohol. Typically the
plunger inside the coil is gummed up. Note: do not lubricate
the coil plunger! It's a dry system, no lubrication (which just
attracts dirt) needed! If someone before you did lubricate the coil
plunger, this may be your problem! Clean it.
Also check the return
spring tension. The return spring pulls the coil plunger mech arm back
after the plunger pulls in. It has to do this with enough spring
strength to move the score reel to the next digit. Sometimes these
springs are old and tired, and need to be replaced (in the short run
you can cut 1/4" cut off to temporarily rejuvenate the tension). This
doesn't happen often, but it does happen. But before doing that, make
sure the mechanism is clean (see previous paragraph). Increasing the
spring tension on a dirty, sluggish mechanism doesn't help
anything!
Manually Moving the
Score Reel.
You can manually move a score reel by pressing in
the score reel coil plunger by hand. Use fast concise movements to
emulate a coil pulling-in the plunger. Do not wrench on the score reel
itself. This will damage the mechanism.
If you want to try a
test, turn the game on and try to start a game. Do the the score reels
move to zero? If not, try manually moving all the score reels to the
zero position. Now try starting a game; does the score motor stop
running? It may or may not, depending on what is wrong. If the
switches are out of adjustment or dirty, the score motor may still
run. If the game starts, just cleaning the score reel mechanism so
they could turn easily fixed your problems!
1970's Bally
and Williams Score Reels: note the zero and nine
position switches at
the lower left on this Bally unit.
A Gottlieb "rat trap"
score reel with no printed circuit board (easy switch
cleaning and
adjustment; no dis-assembly required).
Score Reel
Switches.
If the game still won't start, it's a good idea to
examine the score reel switches. You'll need to clean and maybe adjust
the zero position or nine position switches. All score reels will have
some sort of cam that opens and closes a set of switches as the score
reel moves to the nine and zero positions.
On 1970's games, this is
real easy to find. These switches are on the outside of the reel, and
easily seen. On early "rat trap" Gottlieb score reels you may not be
so lucky. You will have to dis-assemble the score reels with printed
circuit boards on the outside to get at the switches (see pictures).
Starting in 1967, Gottlieb switched to the "decagon" score reels (the
reels themselves are a decagon shape, and are not round). The switches
on these units are much easier to access.
A Gottlieb
"rat trap" score reel with printed circuit board
(dis-assembly
required to clean and adjusts the switches,
which live under the
board).
A Gottlieb "decagon"
score reel, as used from 1967 and later.
Note the switches are much
easier to access, even with the
printed circuit board in
place.
Once you have access to
the zero and nine position switches, manually move the score reel
solenoid. Note how the switches operate, especially when the reel is
at the nine and zero position. If it's not obvious what is happening,
compare to a functional score reel to figure it out.
When the score reel is
in the nine position, it closes one or two switches which tell the
next score reel in line to move up one when the current score reel
advances to zero.
Gottlieb
Decagon Nine, Zero Position Switches:
The decagon score reels provide
easy access to
these switches for cleaning.
The zero position
switch(es) tell the score motor when the score reel is at the zero
(reset) position.
Clean both of these
switches with your flexstone. And make sure they operate with a good
wiping motion, and adjust accordingly. But be careful in adjusting the
zero and nine position switches. There is a balance between switch
blade tension and the amount of "horsepower" available to turn the
score reel. If the switch blades have too much tension, the score reel
may "hang" and not move past the nine or zero positions. This is a
common problem, and some (incorrectly) change the return spring
tension to try and compensate for it.
Gottlieb "Rat
Trap" Reel: Remove the three screws so the metal
score reel can be
removed from it's cam. Do not remove
the retaining clip from
the cam shaft! With the reel removed,
use some 600 grit sandpaper and
clean the printed circuit board
traces so they are shiny. Note the
alignment pin on the nylon
hub. This lines up the score reel when you
replace it.
Gottlieb "Rat Trap"
Reel: After removing the two screws from the
printed circuit board,
you can slide it out to get at the
nine, zero position and EOS
switches.
Cracked Solder
Joints On Williams Score Reel Switches.
Williams games have a
particular problem with cracked solder joints on the wires soldered to
the score reel switches (zero, nine and EOS switches). This happened
because of an inferior manufacturing technique William's used to
attach wires to the solder lugs. This can cause game reset problems.
It's a good idea to pull on each wire going to these switches to check
for cracked solder joints. It's almost a guarentee you'll find at
least one wire with a cracked joint on any Williams games. To
properely fix this, cut the wire(s) clean and twist together. Heat
them with your soldering iron, and apply some solder. Now heat the
solder lug on the score reel and flow the tinted wires into this
joint. A smooth joint will not break.
Clean the Score Relay
Switches.
Each of the score reels is driven by an associated
relay. Since the score reels get considerable use, you can also assume
the relays that drive them do too! Because of this, you should clean
ALL the contacts on each score relay. There will be about five
switches (more or less) per relay. At least two switches will activate
the score reel itself (and maybe the next reel in the line for when
the current reel's score moves from "9" to "0"). One of the switches
will go to the bell solenoid for that score reels. Clean all the
switches with your flexstone. Also check that the switches are
adjusted correctly with a good wiping motion (as described in the
switch contact section).
Williams Score
Relays: shown are the three relays in
the lightbox that control the
four score reels. Note the
absence of a fourth score relay (for the
10,000 score reel);
that score reel only gets advanced when the
1000's relay
hits "9", and hence doesn't need its own
relay.
The Score Reel EOS Switch.
Each score reel will have
an end-of-stroke (EOS) switch for its coil. This normally closed
switch will open as the coil plunger reaches its end of stroke when
advancing the score reel. Making sure this switch is clean and
adjusted is very important!
The EOS switch's purpose
in life is to break the power going to the score relay. If this switch
never opens, a score relay can get stuck on. This can lock on the
score reel coil and any feature (such as a bell or chime) wired to the
score relay. This EOS switch needs to be cleaned and adjusted
properely.
What about a missing or
broken score reel EOS switch? In reality this is usually Ok, and very
common. Often one of the blades on the EOS switch breaks off (from
constant use). This leaves the circuit permanently open. Again, this
is Ok in most cases. The only problem that can occur is if the EOS
switch becomes permanently closed, not open! If you have a broken
score reel EOS switch, just forget it. Don't replace it (unless you
are comfortable with this repair and insist your game works just like
the factory intended). Having a broken normally closed EOS switch
blade only makes the pulse slightly shorter for the score reel to move
to the next position. The exception to this is if the EOS switch is a
3 blade make/break switch or a normally open switch. In this case it
is performing a carry function and is critical.
Testing the Score
Relays.
Once the score relay switches are filed clean and
adjusted, test them. (Even if you have a 1950's EM with no score
reels, it still has score relays that connect to the score stepper
units instead of score reels.)
On Gottlieb games, you
can only test the score reel relays during a game. On Williams and
Bally games, just turn the game on. Manually push each one of the
score relays in by hand. The score reel it controls should advance.
Note: when doing this in "game over" mode, if "0" is reached on the
score reel, it will NOT advance the next score reel. But if you do
this test in the middle of a game, when a "9" is reach, manually
pressing the score relay again will advance the next reel one step
too.
Gottlieb "Rat
Trap" Score Reels and Relays (Buckaroo): notice
the three relays to
the right which control the three score reels.
Since this game has a
lighted fourth "one thousand" score, there
is one relay for each
score reel (unlike the picture of the above
williams relays where
one of the four score reels doesn't have a
corresponding
relay).
If you start a game and
manually test the score relays, check the "9" position of each reel.
That is, advance a score reel to the "9" position. Now activate the
score relay again. Does the next score reel advance with the current
reel? If not, the "9" position switch on the current score reel is
dirty or out of adjustment (or you're testing the highest score reel
in the numeric set!).
Remember, on Gottlieb
games, you can only test the score relay during a game. So if you
can't start a game at this point, you can't test the score relays.
This is unfortunate, but there isn't any alternative.
the "Art" of Manually
Activating Relays.
As dumb as this may sound, there is actually
an "art" to activating a relay by hand. If done incorrectly, you can
mis-align the relay and seemingly make a working relay into a
temporary mess.
Each relay has the coil
itself, a pivot point, and a metal activating lever plate with a
plastic or bakelite piece that the switch ends ride in. To activate a
relay, press the metal plate in towards the coil. But be careful, if
you press with a sideways motion or press too hard, sometimes you can
knock the metal lever plate off its pivot point. This will mis-align
the switches and cause chaos. It's easy to fix, but you may not notice
the mis-alignment at first. And you'll be tearing your hair out trying
to find the problem, and wondering why all the switches in this relay
need adjustment (when in fact they didn't)!
Score Relay Stuck On?
This is a common problem. One
of the score relays is stuck on as you start a game. A lot of times
people don't notice this till they smell the score reel solenoid
burning! A sure sign of this is a score reel doesn't register points.
This happens because the score reel solenoid and the score relay are
both pulled in and won't release.
Check all your playfield
switches; one is probably "on", thus locking it's corresponding score
relay on. If you can't find any playfield switches on, it could also
be a feature relay switch that is stuck on. For example, the Fifty
point relay has a stuck switch which connects to the score
relay.
Some other things that
cause a score reel to stick "on":
- Score Reel EOS Switch
is dirty or permanently closed (see above).
- Two solder lugs of a
switch are bent and shorting together.
- A single loose strand
of the multi-strand wire is broken and bent, shorting to another
solder lug.
- The vibration damping
blade is shorting against the other adjacent switch blade.
- Pitted or
mis-adjusted contacts driving the score reel. Until the score reel
takes its step, it won't release the score relay.
A Mis-Adjusted
Playfield Switch: Notice the damping blade in the middle
(which
dampens the upper contact) is shorting to the lower contact. Yet
the
contact pads are adjusted correctly. This is visually
deceiving.
Of the above listed
problems, the last one is the most common! A lot of times you just
don't noticed it. But if you look at a playfield leaf switch, you'll
notice it consists of two leaf blades with contacts. BUT there is a
third, shorter blade. This blade is the vibration damping blade. It
provides support to ONE of the blades. Yet sometimes this damping
blade is bent and shorts against the other blade. This will lock a
score relay and/or feature relay on.
2e. Before Turning the
Game On: Stepper Units
The other common
failure in EM games are the stepper units. Steppers have at least one
coil that "steps up" the mechanism, and often another coil that "steps
down" (or fully resets) the mechanism. Often these units bind.
Stepper units are used
for a variety of uses. If you have a 1950's EM game, they are used for
the lightbox scoring. There's a stepper for each scoring range
(thousands, ten thousands, etc.). Each stepper will have a step up
coil, and maybe a reset coil (to reset the points to zero). Usually
the lowest scoring stepper (like the zero to 10,000 point stepper)
won't have a reset but will just rotate around to the zero
position.
(Left)
Bally Stepper Unit with no step-down or reset coil. This unit
is
known as a "00 to 90" unit, and is used for the
match.
(Right) Bally Stepper Unit used for ball number with
both step-up
and reset coils.
 
Other uses for steppers
are counting bonus points, keeping track of the current ball number,
matching (at the end of a game), keeping track of number of credits,
and keeping track of the player number (for two and four player
games).
Each and every stepper
unit in your game needs to be examined, cleaned and manually tested
for proper operation. Common problems associated with stepper units
are:
- Score motor continues
to run when a new game is attempted.
- Game credits not
added or taken off.
- Current ball number
in play never changes (always stuck on ball 3).
- Can't change number
of players on multi-player games (only 1 player allowed or won't
reset back to 1 player).
- Bonus points don't
work properly.
- Match number always
the same.
- Score won't reset to
zero (1950's games with lightbox scoring).
(Left)
Williams Stepper Unit showing the wiper fingers and printed circuit
board.
(Right) Williams Stepper Unit with a step-up and
step-down coil.
 
Note the metal wiper
"fingers" on each stepper unit. These wiper fingers determine the path
the electricity takes for each step of a stepper unit. The wiper
fingers move across a series of brass rivets or across a printed
circuit board. These rivets or circuit board must be clean for good
contact.
To clean a stepper unit,
follow this procedure:
- Turn the power off to
the game!
- Un-bolt the stepper
from the board it is attached to. Not always necessary, use your
judgement.
- Set the unit to the
reset position. This is only necessary on steppers that have two
coils (a step-up coil, and a step-down or reset coil). Using a
"Sharpie" pen and mark the zero position on one of the wiper fingers
and on the board it runs across (for future reference, otherwise you
could assemble the unit 180 degrees in reverse!).
- Remove the SPRING
that winds the unit. Again, this is only necessary on steppers have
have two coils. While you release the spring, COUNT the spring
winding as you un-turn the spring. Write the number of turns on the
stepper unit with your Sharpie pen.
- Remove the one or two
coils that step-up or down the unit. Clean the plunger(s) with
alcohol, and if rough sand the plungers smooth with 600 grit
sandpaper or a scotchbrite green pad (do NOT use steel wool!). Put
in a new coil sleeve (if possible). Do NOT reassemble the plunger(s)
at this time.
- Remove the NUT at the
end of the turning wiper shaft. This will remove the wiper fingers
from the shaft. Usually the shaft will pull out from the other side.
Clean everything with alcohol, and if rough, sand the shaft smooth
with 1000 grit sandpaper or green pad. You may have to remove a
mechanism spring or two to get the shaft out. Make notes and
drawings as to where the springs and levers go.
- On Gottlieb stepper
units, sometimes you need to remove three screws on the other side
of the stepper to get at the brass rivets that the fingers touch.
Mark the disk orientation with your Sharpie before you remove the
disk! See picture below. Also note you may have to make fine
adjustments of the wiper/rivets alignment here. And while the
wiper/bakelite disk is removed, use an allen wrench and tighten up
the three prong holder the disk bolts to.
- Sand the bakelite
disk with the brass rivets or the printed circuit board that the
wiper fingers glide over. Use 1000 grit sandpaper or a green pad.
Green pads work really well, except on Bally units. Those clean up
best with sand paper because of rivets don't have round heads.
Almost need to block sand Bally flat heads to clean properely. Make
the brass or cooper shine.
- Re-assemble the shaft
and wiper parts. Use CoinOp oil, light 3-in-1 oil, or Radio Shack
teflon grease on the shaft. Don't use much! VERY LIGHTLY lube the
brass rivets or the printed circuit board on which the wiper fingers
glide.
- Put the nut back on
the wiper shaft, and make sure your wiper finger Sharpie lines match
up when the stepper unit is reset.
- Wind the spring back
to the same number of turns.
- Re-assemble the
plungers and coils (DO NOT lube!).
Now manually test the
unit. It should step up nicely, and step down (or reset) nicely. If
there isn't enough spring tension to reset or step down the unit, wind
the spring one more turn.
(Left)
Gottlieb Stepper Unit. Note the different usage and type of wiper
fingers.
(Right) Williams Stepper Unit used for
matching.
 
* Go to the EM Repair Guide Part
2 at
http://www.bigbox.ch/pinball/repair/index2.htm
* Go to the Swiss Pinball Site
|
