While the playfield dried I started to reassemble the playfield
actuators (slingshots, flippers. popbumpers, etc). I ordered
various new parts from
as coil sleeves, a new rubber kit, flipper parts, etc. Each
the actuators were completely disassembled, sanded with 400 grit
paper, tumbled in the vibratory tumbler overnight, and then reassembled
with new coil sleeves. Some coils were replaced, and the
Sampling of the major actuators for the playfield after refurbishment
reassembly. "T" target,
ball saver post, 3-bank target,
and the two flippers. Due to missing or worn parts on the
almost all of the parts
on the flippers are new.
Note the connector I devised for the switches on the 3-bank drop
This allows me to reinstall it more quickly.
By using the C-clamps and some solid teflon blocks, I can flip the
to work on the bottom side
without fear of marking the clearcoat. The white mass in the
photo is the teflon block.
Pinball Playfield Tester
Since I did not know the operational state of Playfield B when I
received it, and also due to the many parts that were removed and
refurbished, I decided to
build a standalone playfield tester.
If I had miswired a solenoid, it could cause damage to the CPU board of
the machine. Also, the machine is several feet away from the
playfield rotisserie, and it would be clumsy to move the two closer for
a test. The tester will allow me to verify every switch,
solenoid and associated
circuitry and harnessing. I was surprised to find no similar
device when doing
a Google search.
Circuit diagram of the playfield tester. All circuits on the
playfield can be tested by this unit. Selector switches
the rows and column of the two
matrices just like the CPU would. In addition, solenoids and
flash lamps can be fired individually.
The completed tester on my workbench. Note the four
connectors on the left and that the
overhangs the left side of the box.
The purpose of that is
Due to the overhang on the top cover, the
tester can be mounted on one of the
beams of my playfield
can be hung on the
sidewall of my
cabinet to test
a playfield that is still installed inside a machine.
As one can see in the
the tester features a copy of the two matrices from the user manual of
the Space Shuttle. A particular switch or light bulb can be
selected by turning the row and column selector rotary
point to that item. Power is provided by a separate current
limited adjustable power supply so that I can limit the amount of
current to prevent damage should there be a short in the wiring.
The connectors to the
four 0.062" style Molex. List
of key connector parts:
Note that the printed
matrix in the
user manual has colors associated with each row and column (see picture
below). It turns out that these colors are those of the wires
the playfield. So although there was no schematic of the
playfield itself, I could tell how to connect the selector switches
based on the color mentioned in the columns and rows. When I
first fired up the matrix, I found that few of the lights worked;
perhaps 25%. Considering the large amount of work to be done,
was glad to have the tester so
that I could work on the playfield from the comfort of my work chair
instead of standing next to the pinball machine.
A particular light can be turned on by selecting its row and column in
matrix of the user interface panel.
One of the few lights that worked is shown in the photograph.
would agree that this tester is very "SPECIAL" 8-).
The bottom portion of the tester. This allows me to test
including the special switches (the three pops, and the two
slings). When a particular
switch is selected and then closed, a beep can be heard. If
switch is noisy
or intermittent, the beep will not be clear but raspy. This
switches that make intermittent contact and that need to be cleaned.
Any of the 18 Solenoids can be tested by clipping the ground terminal
to either continuous ground or
switched ground. In the latter case, I can use a momentary
to fire the solenoid. BLAM!
Solenoids are tested by
their return terminal. A momentary switch is provided to
pulsed operation. I also intend to test the diodes on all the
coils by reversing the polarity of the power and verifying that the
coil does not fire. This is important as an open diode will
suppress the large EMF kick of the coil, and could damage the driver on
the CPU board.
The insides of the tester. I intentionally left space in the
right corner in case I one day
decide to mount a microprocessor in there to
scan the matrices
Update: In February 2006, I sold the above playfield tester for $60.