Quoted from 20SidedDies:Can anyone post a “cure all video” for how to check every possible issue that can cause the cannon to not move? And if (it exists) a video of replacing/repairing one? It’s crazy to me this doesn’t already exist somewhere. - a repair video on the canon I mean.
As far as pinball repair goes, a lot of things are simple, and some are harder, and some require a technician to fix.
As an experienced pinball technician, this is no mystery. I'm surprised that you find it difficult.
But if you are entirely inexperienced, I recommend you get an actual pinball technician to come out to your home and repair your game.
Some problems require a technician to fix. This may be one of them.
If you are up for fixing this yourself, you need to know that your game has a manual:
https://www.ipdb.org/files/2524/Williams_1991_Terminator_2_Judgment_Day_Manual.pdf
The basic idea behind how things work in a pinball:
Power is applied to something all the time. Flashlamps, coils, circuits. The Power Driver board connects ground to complete the circuit through the 'driver transistors'.
PDF page 48 will tell you that the gun motor is solenoid 11, and that it is Q54 (driver transistor) on the power driver board, and that the wire to make the connection is J127-4.
So this will be the side that connects ground to the motor.
PDF page 111, and you have a 'top level' wiring diagram. This shows that the motor (through the coils on the EMI board) is connected to power through the Motor Regulator assembly, and the motor get's a ground path through J127, pin 4, which is connected to Q54. All this makes sense, and we have a complete idea about how the motor is going to get connected to ground.
Now we need to look at how the motor is going to get power.
On PDF page 78, you have the parts and layout of components of the A-13892-2 Motor Regulator Assembly. On PDF Page 110 is the schematic for this board.
PDF Page 110 is actually pretty important, it tells you that the Motor Regulator assembly get's it's connection to provide power from two other connectors on the Power Driver board, J107 pin 5 (lots of things get power through this pin!), and J118 pin 3.
So it's pretty clear that this Motor Regulator will get power and ground from an unregulated 20v source, and output a 'regulated' 12v to supply power to the motor.
That's the diagram at the bottom of PDF page 110.
Now, you think there should be 'every possible cause' troubleshooting... Seriously?
Well, start with is your city connected to a working power plant. Does your neighborhood have power. Does your house have power. Do you have power at the outlet. Is your pinball plugged in at the outlet. Is your power wire connected inside the pinball...
Seriously? EVERY POSSIBLE cause?
If I was troubleshooting this, the first thing I'd do is put my red meter lead on one of the motor terminals, and my black meter lead to the ground strap in the bottom of the cabinet. Measure DC voltage. Until the motor has a ground path, both motor terminals should have power. If I read power at the motor, then the only reason the motor won't have a circuit with power on one side and ground on the other side is that there is a problem with the connection to the ground side.
So if you've got a problem on the ground side, take an alligator clip, attach one side to the ground terminal on your Power Driver board in the backbox (look for it, it's in the middle of the board), and touch the other end of the alligator clip to the tab of the transistor that runs the motor. Does the motor turn? Then it appears that maybe Q54 isn't working. You've got a good path from the tab of the transistor, but the transistor isn't connecting ground? Probably the transistor. Replace it with a TIP102. While you've got the board out, look at the predriver transistor (it should read just like all the other transistors in the circuit. This is typical board repair.
If you don't feel that you can do typical board repair, hire a technician to do this. Any competent pinball technician would find this trivial.
But suppose you ground the tab of the transistor, and nothing happens.
At this point, I'd clip the alligator clip to the tab of the transistor and go back underneath the pinball to the motor. I'd put my red lead to one motor terminal, my black lead to the other motor terminal. If I read voltage here (like 12vdc), I have a defective motor. Power to the motor is being applied, but it isn't turning. You need a motor.
If I don't have power, I'm suspecting connections. Something is not connected.
Motor EMF boards have coils. It is quite common for the solder connections to these coils to be broken, or the solder connections on the connector pins to be broken under the board. So reflow the solder to these connections.
For the motor to turn, it needs power and ground, 12v on one wire, ground on the other.
This really isn't too hard to trace. You'll need a meter, you'll need alligator clips.
The book is quite clear where the connections are. It's quite clear what voltages (or ground paths) are present.
But, unless you get a technician to look at this for you, YOU are going to have to figure out what's wrong here.
Are voltages present? Are ground paths connected? There are only so many places you can have a problem, but I'm not going to be able to diagram out thirty or forty paths that COULD be this issue. You'll have to find out what is working and what isn't to narrow the range of your problem.
Many people here get to a certain point here on pinside, and ask some questions.
What I've outlined here should get you started.
Let us know how far you get in your troubleshooting, and we can probably help you further.
If this description is beyond you, hire a professional.
Cleveland, OH
