help pls, hit to jet bumper causing pin to TILT

vintagegamer

Well-known member

Donor 2024
Joined
Sep 1, 2007
Messages
21,092
Reaction score
2,602
Location
Bear, Delaware
I'm trying to research this issue- for some reason, at any unannounced time, if the ball hits one of the jet bumpers on the playfield, the hit will result in a TILT and will sometimes even put the game into a multiplayer mode after.

It's always the same jet bumper that prompts the tilt, and it doesn't do it all the time. I lifted the playfield and hit the switch by hand 30x in a row and it didn't tilt, so I'm not sure what's causing the problem. I popped the top off of the jet bumper and the game never tilted, I put the top back on and it starts tilting again. It's crazy.

I read on the marvin3m site that sometimes a dead diode will cause the game to do weird stuff- is that what I'm running into here? Anyone seen this before with one of their games?

It's my Time Warp pin that it's happening on, and it's the 1st jet bumper of the 5 blue jet bumpers in the series on the playfield.

I bent back the playfield switches so they would not come in contact with each other, I put electrical tape on the slam switch to block the contacts, and lastly I removed the weight from the plumb bob so it wouldn't hit the ring around the weight. Even with all of this done, this tilt function is still happening, complete with the 'tilt' light registering on the backglass.

Thanks to everyone here, this game is now playing great with the exception of this one issue- couldn't have done it without you guys!!
 
Last edited:
I'd check the wiring inside that goes to the light and see if it's shorting. Does it blink at all when the ball hits it?

Also, doing it manually wouldn't have caused any vibrations. Maybe there's a cold solder joint in there that's causing it to flake out a bit when it vibrates.
 
I'd check the wiring inside that goes to the light and see if it's shorting. Does it blink at all when the ball hits it?

Also, doing it manually wouldn't have caused any vibrations. Maybe there's a cold solder joint in there that's causing it to flake out a bit when it vibrates.

I think the bulb in that jet bumper was one of the ones I had to replace when I first got the game, but I'll have to go back and double-check. It lights as it should during gameplay and attract mode as far as I can tell, but obviously something's gotta be not right in there or I wouldn't be having this tilt issue, right? :D

I will be sure to take a look at it again and see if I can spot anything more specific regarding the behavior. It's crazy that it's just happening with this one jet bumper and at no other time! Then again, I should probably be grateful for that!
 
I just finished reviewing the switch matrix (again), and it indicates that on row 3 (wht-orange wire) the following switches exist:

1. credit button
2. left top jet bumper
3. playfield tilt

I have noticed that when the tilt error takes place upon the hit to the left top jet bumper, and the game resumes on the next ball, sometimes the number of credits has jumped from a single player game to a 2-player or even up to 4-player. It's logical considering the credit button is in this same row of switches.

I'm glad to have found this info, but I'm not quite sure of how to troubleshoot it- obviously the row is getting power since everything is functional. I can check to see if there's a lower power output at the corresponding pin, but after that, I could use a little direction. I bent the playfield tilt switches apart so that they would not make contact, so I'm not quite sure of how a tilt could still result. The only theory I can come up with for that to happen would be that either: a. the MPU is briefly mistaking the jet bumper switch for the tilt switch, or b. it's one of the other tilt switches being impacted to make the tilt. (I'm guessing b would be a longshot since the playfield switch is included in that row)

Since troubleshooting pins is relatively new to me, I'm now taking suggestions. :D Would it be any help if I cut one end of the jet bumper diode to see if that made it stop? I'm just grabbing at straws now.
 
Last edited:
Today's updates:

1. tried playing again with the top off of the bumper, this time it tilted even with the top off (so much for that theory)
2. checked the wire going from the light in the bumper through the mount, and it was touching the mount so I though maybe it was shorting out or something; put electrical tape around wire and mount so they would not make contact, problem still exists
3. after watching it happen a few times, I noticed that it's happening sometimes when the ball bounces from one specific jet bumper to the one that results in the tilt. All of the jet bumpers are on the same switch column in the matrix- could the closing of the 2 switches at the same time be resulting in my problem? Maybe I should space the switch gap out a little bit on the 2 bumpers in question?
 
All the things you've done to try to diagnose and fix your issue shouldn't fix them nor be a problem in this scenario. So, don't worry.

My knee jerk reaction is that the diode on there is shorted out. Is the tilt on the same row/column as the bumper in question? What happens is your diode doesn't stop the info from traveling back up to the switch matrix, therefore going to activate other things on that same row/column... in this case, the tilt as well. Replace the diode, and come back to us. Should be an N4004, I think.

If this doesn't do the trick, there are times when two switches at once can make one other one go. I had this issue on my twilight zone. If you held down one switch, and then pressed another switch, that would make the tilt activate. What was wrong was there was a mis-placed diode that cause the one column and the other row's common denominator fire. Let me try to show what I mean in a poorly done diagram of the switch matrix.

xxxxxAxxx
xxxxxxxxx
xxxxxxxxx
xxxxxxxxx
xxBxxCxxx

Holding down both A and B would make C fire! The reason is because C was in the same column AND row as the two switches going off, and since the diode wasn't doing it's job, the machine assumed that C was being pressed as well.

I don't think this is your issue, but after replacing the diode, we know there's somewhere we can still go.
 
Last edited:
My knee jerk reaction is that the diode on there is shorted out. Is the tilt on the same row/column as the bumper in question? What happens is your diode doesn't stop the info, therefore going to the tilt as well. Replace the diode, and come back to use. Shoul be an N4004, I think.

Sounds like a good idea, could be going back through the switch matrix and setting off the tilt.
You mentioned the credits are jumping up too, which is also on the same switch row.

I'd just replace the diode and see what happens, it's such a simple/cheap fix.
 
Thanks all- another person on the rec.pin forums thinks it's a coin switch that's contributing to the problem as an another possibility. The marvin3m site indicates it could be the diode as well.

I'll see if I can hit the parts store on the way home and pick up a new diode. I'm just always worried I'm gonna hook it up the wrong way because I haven't done much work with diodes. I'd like to follow the layout of the current diode that's in there but I need to make sure the current one is installed the right way first.
 
Thanks all- another person on the rec.pin forums thinks it's a coin switch that's contributing to the problem as an another possibility. The marvin3m site indicates it could be the diode as well.

I'll see if I can hit the parts store on the way home and pick up a new diode. I'm just always worried I'm gonna hook it up the wrong way because I haven't done much work with diodes. I'd like to follow the layout of the current diode that's in there but I need to make sure the current one is installed the right way first.

It won't necessarily be the diode on the switch that's causing the issue but that's a good place to start. I would check through all of the diodes in the switch matrix. Starting with the ones adjacent to the switch causing the problem. Assuming all of the switches are open you could do that at the connector where the switch matrix connects to the MPU. Remove that connector and check through all the diodes using the schematic. Alternatively you could go to each diode individually.

Here's a though... why not actually TEST the diodes. Replacing it and hoping for the best will not be your most effective method of troubleshooting :)
 
Last edited:
Tonight's update....

1. checked the current diode that's installed using my DMM on its diode setting. When I had the red lead on the anode and the black lead on the cathode side, the reading was "716". When I did the reverse check, it simply read "1" (I'm guessing that's for infinity)

2. checked the diode on the bumper that is 1 step before the tilt (the one that the ball hits first and then hits the one that causes the bumper after), its readings were similar to #1 above- they were "746" and infinity.

3. tried the game with the coin door disconnected from the harness, it still tilts.

I bought a pack of new diodes but haven't swapped any out yet. Awaiting further suggestions :)

EDIT: I forgot to mention I did not clip one leg of the diode, do I definitely have to do this?
 
Last edited:
Well, last night I pulled the connectors from the driver board and checked the diode, it read that it was OK. I desoldered one leg and checked the diode again, it still read OK. Even though it was reading OK, the lead on the anode side looked tarnished, as if it had taken some sort of heat or power surge at some point. I said F it and replaced the diode. Powered up the game and..........

IT'S FIXED!!!! I even had my wife and my daughter play repeated games trying to tilt the blasted thing by hitting the bumper in question, and it never tilted once! I'll keep watching it but I had to share this glorious update! THANK YOU TO ALL OF YOUR FOR YOUR HELP!

All that's left is getting the sound board working 100% and I'll be golden. Thanks again!


VG
 
Back
Top Bottom