Alien Poker Multiball

Alien Poker is a great pin I think (almost as good as firepower...), but there is one problem:
It is only single ball.
In my opinion it is perfectly prepared for multiball:
There are three eject holes on the playfield.
Before the eject holes, there are arrows lamps.
I don't know why williams didn't release this pinball as multiball pinball.
I started a little project to convert my alien poker to a multiball machine.

Here are the new game rules (based on the ideas from another williams collector Christophe Champault):
1) Light P-O-K
2) Upper eject hole is lit (the extra ball setting is used by the way...)
3) If the first ball is locked in the upper hole, the second ball is served and the right eject hole is lit.
4) If the second ball is locked then the third ball is served.
4a) or when the second ball drains, then the first ball is unlocked.
5) When the third balls scores the first point (or drains) then the two balls are unlocked.

I have to modify the following things (hardware and game roms):

Install a ball trough (coil , switches)
add a lamp
enlarge rom size

Ball trough:
As a single ball machine, alien poker only has one coil in the outhole assembly:

There are different solutions for multiball assemblies:
In bally multiball pinballs (except xenon) only one specialized coil is used and the balls are stacked in the drain area:

I tried this configuration, but the power of the orignal outhole coil was to weak. (in bally pinballs the coils are powered with 43 Volt, in williams it is only 28 volt)

Gottlieb found a nice small solution for this problem:

They use two coils but they put all coils under the apron.
I will try this solution if I can get the gottlieb hardware.

In williams mutliball pinballs two coils are used for the outhole assembly.

One coils is under the apron (the same coil and the same place as in alien poker) and one at the right side under the plunger. (right down in the corner of the next picture)
Here you see the dowside of a firepower playfield:

Here you see the downside of my alien poker playfield:

We have a little space problem here. If I move the playfield tilt switch around, I will get additional place to mount one flipper assembly in the same way as in firepower...
But there are two flipper assemblies on the right side...

There is another major difference:
You need three switches to detect that all balls are in the ball trough. So williams made a large hole under the apron in the playfield to store the three balls and to mount the switches:
I made a template out of my old firepower playfield:

You can download it

Now let us start:
Use a dremel and cut down this little metal tube.

Mount the screws from the two bonus lamps (20 and 40) to a new place:

Remove the switch under the right slingshot and the lamp under the right slingshot. We need this place here for the flipper assembly.

Remove the lamps from the bonus multiplier, mount the screw from the extra ball lamp to a new place.

Move the lower right flipper assembly to a new place:

You can remount the bonus multiplier with the exisiting screw:

Mount the screw from the special lamp to a new place and move the upper right flipper assembly to a new place:

Remove everything fom the outhole assembly except the upper metal boarder.

Mark the excat position from the template.
Use a jig saw and cut the wood.

Don't touch any wires with the jig saw !!!

For the hole I use a forstner driller.

(I made some tests with a junk playfield, so you see pictures from two playfields.)
Now we have a nice place for our outhole assembly:

Now we can mount the firepower assembly:

I made another template with the old firepower playfield for the screw holes:

Next problem:
The metal plate from the outhole switches doesn't match:

Ball ramp thrower and all three outhole switches are mounted:

Take the two wires from the playfield tilt switch and solder them to the three outhole switches. Make sure that you wire the three switches in serial (use only one diode...).

My game rom must know when all three balls are in the ball trough. I use these three switches in the outhole assembly
So this switch will only be activted when all three balls are in the ball trough.
Important: Make sure that this switch is only closed when three balls are in the ball trough. Go into the switch test, put only two balls in the ball trough and push them around from the side, this switch shoould not register !
Mount also the outhole switch from the firepower playfield. (replace the existing switch...).

Mount the rest of the firepower assembly:

Trough coils:
All coils are used in the alien poker, so I reused the kredit knocker.

Remove the blue wire from the credit knocker and solder it to a connector.

Wire the other part from the connector to the ball ramp thrower. Wire the large red wire from the ball ramp thrower to the coil from the outhole assembly.

Additional lamp:
Both arrows from the upper and the right eject hole are wired to the same playfield lamp.
Because I want an easy multiball sequence (always upper hole for the first ball lock, then always right hole for the second ball), I need another lamp for for the right hole arrow.
There is one unused lamp (number 48) on the playfield. But this lamp is used internally from the game rom. So I have to reuse an existing lamp.
I decided to use the playfield credit lamp.

Solder two wires to the arrow lamp under the right hole.

Connect these two wires to the playfield credit lamp. Remove the bulb from the playfield credit lamp. Of course disconnect the existing wires from the arrow lamp.

Here you see the new playfield switch matrix and the new coil layout:

Ups, one thing I almost forget:

I increased the size of the game rom (about 800 bytes) so you have to make the "firepower mod" to your level 6 board. I tried the zig / zag method, it doesn't worked, so I used the ducan brown method...

One collector in france had a good idea for the multiball assembly:
He used a gottlieb assembly:

He still has some switch problems...

Game roms
Today there is a great simulator plattform around for these pinballs:

Here is a vpt ALien Poker Multiball Table. Alien Poker 2.2 multi.vpt
It will work with vpinmame 1.52 and above versions. The author of this table gave me the permisson to release his table with my modification.

I reprogrammed the williams roms and I did a lot of playtesting with pinmame and vpinmame. (Thanks to pacdude, gaston and kristian for their help with vpinmame script programming , pinmame and playtesting...)
I created almost 14 different version of the game rom (and increased the size of the game rom about 800 bytes) until I was happy with the result. Here is a short description:
The game rom of a single ball machine is event driven and works in the following way:

Wait if any switch is hit,
detect which switch was hit ,
call the specific switch routine (for example add 1000 points)
go back to the beginning of the program

One problem of this method is that multiple switch hits during a short period are not detected properly (also in these game roms the is normally a routine coded, where a permanent closed switch is suppressed for the detection).

When you use this game rom in a multiball machines, two quick hits from an outhole switch are not recognized properly (for example if two balls drain together...).
So the multiball game rom has another program structure (found this out with version 9 of my game rom...):

Ask if a critical switch (for example outhole switch) is closed
if yes call the specific outhole routine
continue in the same way with all others critical switches
then wait if any other normal switch is hit,
detect which normal switch was hit ,
call the specific switch routine (for example add 1000 points)
go back to the beginning of the program

A permament closed ctitical switch (for example an outhole switch) will result in a permanet pulsing outhole coil...

Other things I did:
I also add a check (after power on) that you could only start a game when all three balls are in the ball trough. Otherwise you will see some "3333" in the player 3 and 4 display.

I added a supress leading zeros in the displays (same way I did it for my firepower 7 digit game rom...)
I need some memory locations in the game rom, so I removed some things:
Tilt counter -> is now 1, this means the settings in the parameters has no effect
Coin counters (1,2,3) -> are disabled and reused for multiball purpose (you will see garbage in the audit mode here...

This game rom only includes the minimum coding for multiball (no specific lightshow), maybe I will release another multiball version with a light and soundshow if there is enough intrest around...
Update: Sometimes after the second ball is locked and the third ball is in the shooter laner, both locked balls are released before a point is scored with the third ball...not sure if this is a switch problem...could also be a timing problem...
This was a software bug. This bug is solved with rom version 210...
Update: 190805
I improved the following things with version 29: do the million animation (1111111, 2222222) when a ball is locked
remove million animation when you reach 1 m, 2 m , 3m
correct a sporadic ball stuck error during million animation
do a little lightshow and displaycountdow when multiball starts
mail me your feedback please

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