Firepower/System 6 solenoids fire at startup

liquidx

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I have a firepower pinball which works perfectly except for one problem: it kicks a ball into the shooter lane on power up. After that, everything works as it should over multiple games.

As I have no other Williams/System 6 games I was wondering what the startup behaviour should be. I'm assuming it shouldn't kick that ball out :) but all the other kickers seem to also fire on power up, like the capture holes.

Should any of them fire? I know some pinballs do this on startup to dislodge stuck balls. I'm just wondering if I'm looking at a global problem or at one solenoid specifically.

Thanks
 
I don't have a firepower, but I do have a Williams Flash (system 6 mpu version) and it does not kick a ball out upon power up. the only coil that fires upon powerup is the door coil on my Flash
 
That would be a problem with the "blanking signal" that keeps the coils from firing at startup. There are details here on how to fix it:

http://www.pinrepair.com/sys37/index2.htm#blanking

On the Firepower that I had, I had cut the circuit trace that carries the blanking signal on the driver board, it just happens to be right by the 40 pin interconnect header and is easily cut when replacing that connector.

Good Luck.

Mike
 
That would be a problem with the "blanking signal" that keeps the coils from firing at startup.

Good suggestion but his coils come ON when he turns on the machine. Also, if the blanking signal is not getting to the driver board you'll have no displays or CPU controlled lamps.
 
That would be a problem with the "blanking signal" that keeps the coils from firing at startup. There are details here on how to fix it:

http://www.pinrepair.com/sys37/index2.htm#blanking

On the Firepower that I had, I had cut the circuit trace that carries the blanking signal on the driver board, it just happens to be right by the 40 pin interconnect header and is easily cut when replacing that connector.

Good Luck.

Mike

Thought of that too, but what Lindsey says make sense, there would be other symptoms. Then again since it's very short, it might be that. I'll replace the 555 timer to see.

At least I know it shouldn't happen to any of the solenoids, so it should be easier to find the fault.
 
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Actually... the blanking circuit could cause this problem but if it were completely missing you would have no displays or controlled lamps but if the blanking signal isn't getting to the 7408s you'll get the coils locking on.

It's been too long since I worked on Williams stuff :)
 
Right Lindsey,

If the signal does not make it to the Driver board, or the chain is broken, then the coils will fire at startup.
 
Right Lindsey,

If the signal does not make it to the Driver board, or the chain is broken, then the coils will fire at startup.

What I'm suggesting is that the signal makes it past the interconnect but not to the 4 7408 ICs but like I said it's been a while since I looked at Williams hardware.

Good suggestions none the less :)
 
You could actually have one of two different problems here. I've seen Williams games where all of the coils will fire temporarily when you turn the game on but they don't usually blow the solenoid fuse. That's what I was thinking was your problem but the fact that the fuse is blowing could mean that the coils are locking on and staying on. I would pull the solenoid fuse, turn the game on and see if the driver transistors are conducting all the time or if they're just being energized for a split second when the game comes on. These are 2 totally different problems.
 
You could actually have one of two different problems here. I've seen Williams games where all of the coils will fire temporarily when you turn the game on but they don't usually blow the solenoid fuse. That's what I was thinking was your problem but the fact that the fuse is blowing could mean that the coils are locking on and staying on. I would pull the solenoid fuse, turn the game on and see if the driver transistors are conducting all the time or if they're just being energized for a split second when the game comes on. These are 2 totally different problems.


The fuses aren't blowing at all, the first scenario is the correct one, It's just a temporary thing on startup.

Last night I traced the blanking signal and it is actually reaching all 7408s.

I did however notice that the solenoids that fire on boot are all linked to the same one (IC2). First impression was that the IC was working the way it should but I doubt all the transistors behind it are bad so I'm thinking I must have missed something. I'm going to look at it in more detail this evening.

Someone has worked on this board before, there are traces of (bad) soldering around the 556, a replaced transistor in the group that controls the solenoids, and traces of burning in that same area. At first sight, what was replaced does work properly. More inspection to follow :)

Thanks.
 
Sounds like you are hot on the trail.

There are few things in life better than the satisfaction of making an electro-mechanical nightmare called a pinball machine, to work properly.
 
I put a logic analyzer on the suspect 7408 and, indeed, it's going high when, based on the inputs, it shouldn't be.

I don't have any spares, so I'll put an order in and post an update when I've replaced it.
 
So I finally got the parts and the time to get back at this.

I swapped out the 7408 and… my problem is still there.

So it's back to the circuit board. Maybe the the 7408 is receiving a short burst of 2 highs just long enough to get a high output and I didn't notice it first time round.
 
Reviving this thread after finally getting the firepower back into an area I could work on it from.

Anyway, it was the 556, or rather the botched soldering job by whoever replaced it before.

It's now replaced and is also socketed. The game plays as it should.
 
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