The Capcom Motor Control PCB - B0023200
Capcom's: Big Bang Bar Pinball

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Pfutz Speak

DATE: September 30, 2020

TO: People Who Own/Maintain Capcom's: Big Bang Bar Pinball

SUBJECT: Motor Control PCB U1 - TIBPAL16L8-15CN, for the ALIEN mechanic

Top View

One of the problems is that the center chip is a programmable PAL chip (TIBPAL16L8-15CN) from Texas Instruments. The PAL chip is not protected, so any functional chip can have its program read. I got a copy of the PAL program. I believe that it is correct, but I do not have any way to confirm this. I do not have the PAL programmer (someone else has to program the chip). I can email you the "EMI_Motor_BBB.jed" file that "can be programmed with older type programmers".

Unfortunately, There is virtually no documentation on this Capcom board (nothing in the manual). After all, Big Bang Bar only had proto-types built before Capcom closed it doors. A few people are considering to make a board that replaces this PAL chip, but as of 10/02/2020, there are none.

There is forum discussing this:
Big Bang Bar Pal chip???

I am pretty sure that the motor is just a plain DC motor. And this board is controled to make the motor spin forward or backwards or brake using 2 solenoid lines and an opto switch to detect its "home" position. The opto switch and opto wires are NOT on this board. Only the 2 solenoids control lines and power.

Maybe the PAL chip functioned like:
Coildriver S30 motor forward
Coildriver S31 motor revers
driver off (open circuit)
driver off (open circuit)
Maybe remove all power to Motor
driver on (to GND)
driver off (open circuit)
motor forward
driver off (open circuit)
driver on (to GND)
motor reverse
driver on (to GND)
driver on (to GND)
Dynamic Braking (Motor shorted)
The other chip (LM339M) was used to drive the motor and was controled by the PAL chip

I am copying the forum (and pictures):

J1 6 pin connector on the pcb:
Pin-6) 12 Volt (for the motors I guess)
Pin-5) 5 Volt (for the PAL I guess)
Pin-3) No Connection (key?)
Pin-2) Coildriver S30 motor forward
Pin-1) Coildriver S31 motor revers

J2 4 pin connector on the pcb
pin-?) Motor +
pin-?) No Connection
pin-?) No Connection
pin-?) Motor -

Here is the the dissassembly drawing of the "Alien Mech Assembly" from the manual (available at The Internet Pinball Database: Big Bang Bar)
Alien Mech Assembly
Item 5 is the Opto board to detect the position of the Aliens. The interruptor (item 2) has 4 stop positions. With one position having a double knotch to indicate Home position. The diagnostic "C2-02: Alien Motor" uses the opto and the 2 solenoids to turn the motor and determine if it is working.

Good Luck!

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