First thing I would do is check all the wiring connectors to make sure they are fully pushed together (under the playfield and at the boards). Then I would make sure there is a big enough gap for the pop bumper switch.

Then turn the machine on and see if the problem is gone.

It sounds like a wire short to me. That is something I worry about happening each time I raise and lower the play fields in my machines.

Sounds like a switch issue. Check the switch for the pop. It should be very close, but not touching contacts (they need to be very close to react snappy). Which "bank" targets are you talking about? Is it the drops? Check there for the switches that may have an issue (short against another metal tab/part).

Check the switch matrix. It appears that the drop targets are each in a row of a pop bumper switch. If there is a short in a switch in one of the rows, either playfield side, or IC, it could either short the entire row, or part of it, depending.

Figure out which pop it is, which target, and look to the PF and DMD for any other switch giving points/lighting up at the same time.

Then, review the switch matrix in the manual, and report back.

I second atomic boy's advice. Start at switch test and report back.

Given what you said, it looked as though most, if not all, of row one of the matrix was shorted on. Do you have the manual? The switch matrix is in there. There are a few things that can cause a row to be out, or partially out:

1) a short somewhere with one of the under PF switches, as in touching against something else
2) a broken diode on one of the switches, which is supposed to stop a the remainder of the row/column from activiating, when only one switch is to
3) a column/row controlling IC can short - this will result in at least one full column/row shorted, with no exceptions.

The coil locking on though is usually another issue, if it is the only coil issue, and that is a blown driver transistor.

Short answer is yes, you have a short somewhere, but it sounds as though it should be two, but hard to believe they are not connected.

What is your experience level?

sorry to hear your having a problem, I went through a similar problem a bit ago... you might read through my string "Sega/Stern Apollo13 coil stuck, blown F21 fuse, mosfet blown... " I ended up sending my board out... I should have it back Monday or Tuesday... besides what is in the string I'll post what it finally ended up being on mine when it comes in...

It shouldn't have been related, but can be. Since the fuse is blown, and you know switch row 1 is locked on, check to see if there are any lights either locked on or not on. This should be evident in attract mode.

Sorry, not a lot of time tonight. A matrix has been used for controlled/insert lights and switches since early SS machines came out.

Do you have the clay guides? I'll give you some good reading to understand this all. These are the guides for DE/Sega, which were the precurser to Stern machines:

http://www.thepirates.net.au/arcade/Pinball/PinRepair/Apr-11/Pinrepair/Pinrepair.com%20Repair%20Manuals%20Apr%202011/Data%20East%20and%20Sega/

No prob. That is why I asked about the lights. I'm dealing with a Whitestar machine now that has a bad bus/data line. I would normally say you have a shorted transistor for a coil locking on, but given there were switch errors, I wanted to make sure it wasn't something more. A bad data line will cause issues with one or two of everything, lights, switches and solenoids.

In anycase, I wonder now if the coil in question in touching a switch close by somewhere, hence grounding both. Have you taken a very good look to make sure nothing is "too close", regardless if touching at the time?

Did you search RGP? From the quick reading I just did, it sounds like you may have a bad transistor...

If it's only the one coil, and it's still taking out the fuse, I agree, result has been a blown power transistor, 20n10l, or whatever they are. Still, that can't be the original cause though, given what you mantioned.

I'm sorry to say, but you should have never let the game continue to be played with a known issue as it tends to escalate from that point and now you don't know what's causing the problem and whether the coil and F21 are part of the original problem or something new.

What could have very well happened is that the switch for the pop shorted on, which tells the MPU to fire the coil for the pop. I'm not too familiar with whitestar so I don't know if the MPU logic uses a one-shot or just looks at the switch state. If the latter, then the coil would have stayed on as long as the switch was made, which in the case of a shorted switch is continuous. Once the coil stayed on, it heated up, current draw increased and probably fried your transistor for that coil. Hopefully it didn't take out any board traces in the process. If you're lucky, F21 popped before any damage was done.

At this point, concentrate on getting your switch matrix fixed. By your description of moving wire bundles causing the issue, I'd be looking closely at all wiring connections to switches under the PF. Look for broken diode legs or diodes touching things they shouldn't.

To test the diodes you need to remove one leg from the circuit (from one lug). If they work properly in the swtich test, and by that I mean you can activate any one of row one, and only that one switch activates, the diodes should all be good.

Intermittent is almost always conenctors ( I feel like a broken record in every post). There may be a broken wire/diode somewhere that is still resting on the contact point, and the vibration may be knocking it in and out of circuit. Check ALL switches in row one, each lug and diode for anything loose or being held on by only a thread of a connection so to speak.

Again, ensure nothing is touching the coil in question, and that the lugs are not touching the steel bracket holding it. I had a coil on my TZ that was slightly touching the holding bracket, and was energizing the powerfield ramp divertor, and the wire ramp it touched, and every metal piece it touch.

It was fun learning of this when touching it and the side rail one day - 70v...

I don't know. I don't know even what to suggest at this point. I have never heard of anything like this before. I suggest calling the Stern help tech. They are pretty good, and may be able to answer this for you, or point you in another direction.

The only thing I can think of is the game logic is getting confused.

I would be tempted swap driver boards, but pull the solenoid fuses, and see if the problem is still there to isolate the possibilities, but you do not have another whitestar system. Know anyone?

You may need to update your roms/code. I was thinking that before, but wasn't sure of the likelihood of that being the issue.

The transistor is still likely done, so you will need to test it, and if there is an internal short, replace that before putting in a new coil.

I’m interested to see if that was the issue. I can’t see a factory reset fixing this, and if not, try updating the roms/code. This may be damage/compromised in a way that is making it act like this. This is really a shot in the dark at this point. I’ve never heard of anything like this either.

Another shot in the dark, but try re-seating the small ribbon cable between the CPU and driver board.

hmm...wow... I learned something new today, which makes no sense quite honestly.

F21 didn't really do the job, as it's supposed to blow before taking out anything, but if the worst thing you do is having to buy a new coil, no biggie.

Glad it got solved.

great job and thanks for sharing the struggle through to fix it!

Not that this helps you now, but I've gone through quite a few TSPPs and for whatever reason the transistors that drive the pop bumpers seem to go bad quite often. Just a heads up for anyone else who has this problem...

Man, am I glad I found this thread. I installed some illuminated flipper buttons in my TSPP this evening. After doing so, the Comic Book Guy standup suddenly stopped registering hits. I couldn't figure out for the life of me what was causing the problem, because it worked fine if I put the game in switch test mode. The problem was only present during actual game play. I spent about 30 minutes checking every connector to see if I had accidentally knocked something loose. Everything looked fine, so I grabbed my computer to see if I could find someone with a similar problem. The first thread I came across was this one, where Dewey mentioned that Chas over at Stern recommended a factory reset. I figured what the hell, so I did a factory reset and ... BAM!!! The game is now back to normal. You gotta love the internet!