STTNG Just Went Berzerk

I've looked through many other posts, but I couldn't find anything like I just experienced. Aside from a weak plunger, the game was working just fine a month ago. I turned it on tonight for the first time in a month:

- on powerup, the constantly tries to launch a ball, but balls don't always eject into the shooter lane, then the balls that do launch go to the VUK and eject back out to the flippers
- then when playing a game, multiple balls into the shooter lane, both at the start of the game and during the game
- when playing a game, left cannon rotates at random, whether its supposed to or not, and tries shooting the ball that isn't there
- I somehow got to warp 9.6 without hitting a single warp and after draining all three balls
- balls would drain, but the game would keep on going and scoring imaginary hits
- there were many more anomalies that I don't recall

I had previously replaced the CPU board as the old one had acid damage, so I can't imagine that has anything to do with it, but the randomness of all the issues certainly points in that direction.

Any other thoughts?

#2 6 years ago

LTG

Pinside member

Hopkins, MN

12y 191K 56,926 24 7

I'd start with running switch edge test and see if any switch that should be open, is closed.

Then check your 12 volts to see if it is steady at 12 volts.

LTG : )

#3 6 years ago

BJR

Staythirsty

Pinside member

13y 75,800 328 4 27

I fought a similar problem and it was low 12v. A buddy had a similiar problem and it was a broken wire on the shooter lane switch. Here is what the switch matrix should look like with 2 balls loaded under the playfield.

IMG_0769 (resized).JPG

#4 6 years ago

KMR

Phatchit

Pinside member

Davenport, FL

11y 73,900 1,460 9

Damn sttng . Check ribbon cables and definitely doba switch test. There are so many optos in that game it can cause crazy things . Also make sure your voltage is ok. This game is sensitive .

#5 6 years ago

TBK

xTheBlackKnightx

Pinside member

8y 128K 4,097 137

The first three steps here (assuming you have already validated that their are no short circuits under dead testing, including broken wires and reseated all ribbon cables):

1) The first thing that needs to be done is disconnect ALL powered modifications that may be installed that are tapping power through the game. If there are, you already may have found your problem.

2) The next thing you need to do is record voltage test points and conduct a comparative average of the values off the PDB. Pay special close attention to the +5 and +12 vdc sections.

3) The third thing is to inspect the switch matrix, as you have powered optos that are going haywire and engaging coils through the improper voltages or a switch short. This includes the trough assembly.

Then, you can isolate the problem.

Don't skip the first two steps, you need this information for further diagnostic troubleshooting, and otherwise you are backtracking things that should have already been done.

Post last edited 6 years ago.

#6 6 years ago

SFV

Hammerhead

Pinside member

Quoted from xTheBlackKnightx:
The first three steps here (assuming you have already validated that their are no short circuits under dead testing, including broken wires):
1) The first thing that needs to be done is disconnect any powered modifications that may be installed that are tapping power through the game. If there are, you already may have found your problem.
2) The next thing you need to do is record voltage test points and conduct a comparative average of the values off the PDB. Pay special close attention to the +5 and +12 vdc sections.
3) The third thing is to inspect the switch matrix, as you have powered optos that are going haywire and engaging coils through the improper voltages or a switch short. This includes the trough assembly.
Then, you can isolate the problem.
Don't skip the first two steps, you need this information for further diagnostic troubleshooting, and otherwise you are backtracking things that should have already been done.

PDB?

#7 6 years ago

ALX

donjagra

Pinside member

14y 72,100 3,402 10 34

It could be the 12v bridge rectifier failing. Use the test points on the board and check the voltage with your meter.

Edit: It may be time to replace the caps on your power supply board. It would explain the lack of error messages and the overall behavior of the machine.

#8 6 years ago

KRS

thewool

Pinside member

This sounds familiar... I know in the past my game also went berserk and just started multiball mid game with loads of chaos. On one occasion I managed to get into the switch matrix and there was a whole line of switches (vertical I think) disappearing at once. I never got to the bottom of this and it hasn't happened in recent memory.

I would advise when this happens quickly open the coin door and get into the matrix to see what is happening.

#9 6 years ago

AAA

pintechev

Inactive member

11y 91,300 4,437

The optical switches are going crazy. Checking the 12v health is definitely where you should start.

Marc

#10 6 years ago

KRS

thewool

Pinside member

Dual post

#11 6 years ago

LTG

Pinside member

Hopkins, MN

12y 191K 56,926 24 7

OP
Quoted from Hammerhead:
PDB?

Power driver board.

LTG : )

#12 6 years ago

KRS

thewool

Pinside member

Hammerhead please be sure to let us know how you get on as I might go back and do the same.

I have a colour DMD and Pinsound installed on mine but I think I had this problem before that...

#13 6 years ago

LTG

Pinside member

Hopkins, MN

12y 191K 56,926 24 7

Quoted from thewool:
I have a colour DMD and Pinsound installed on mine but I think I had this problem before that...

Unplug power to the color DMD, play a game blind. Then you'll know if you have a power issue or not. Some people have used a separate power supply for the color DMD in STNG .

LTG : )

#14 6 years ago

KRS

thewool

Pinside member

Quoted from LTG:
Unplug power to the color DMD, play a game blind. Then you'll know if you have a power issue or not. Some people have used a separate power supply for the color DMD in STNG .
LTG : )

Cheers for the suggestion LTG, the problem is this only happens once in a blue moon. I would say since I've owned the machine it's happened maximum 5 times, it's totally intermittent. Then the times it's happened it's all over in < 1 minute, that particular game is ruined but then after that it can be fine. I wish it was a permanent fault for a change.

#15 6 years ago

TWB

Djshakes

Pinside member

San Diego, CA

7y 70,550 1,666 2

I had a STTNG that went crazy. After I replaced a bridge rectifier it stopped.

Here is my thread.
https://pinside.com/pinball/forum/topic/100-sttng-fix-me-challenge-experienced-techs-only

#16 6 years ago

KRS

thewool

Pinside member

https://vimeo.com/227561710

Hi there LTG. By chance I was fitting some new speakers and sub into my STTNG last night. I powered her back on and starting getting the odd behavior in game that I described (everything going off at once). I left the switch matrix on and captured on video what happens:

Fast forward to about 1 minute to see the action, it looks like all the optos activating. Just after the video stopped the same thing happened again and a most of the third row from the left disappeared.

Hope I'm not hijacking this thread buy maybe the OP is having the same problem. Hammerhead have you checked out your switch matrix during your issue?

#17 6 years ago

KRS

thewool

Pinside member

Think I might have found my own problem. Tracked it back and J118 was toasted, well done... Went into the switch test and wiggled that connector and the game went mad. Replaced it and the test seems better. Will give it a good game tomorrow.

Hammerhead, check your J118.

#18 6 years ago

KRS

thewool

Pinside member

Just to document my issue... was still having an issue with a dodgy opto. Left the game in switch matrix test and very infrequently left lock 2 (switch 35) kept showing up for a split second. Good job the matrix displays the last switch triggered. I took out the left lock mech and tapped the suspect opto board with a screwdriver - sure enough that was the problem. Reflowed the solder to all joints and it still failed the tap test. Replaced the transmitter and all seems good, left in switch test for ages and no random triggers - now for a few games!!!

#19 6 years ago

SFV

Hammerhead

Pinside member

I finally had a chance to look at this last night.

12V measured 12.1V, so no issues there. I went into switch test mode and sure enough some (but not all) optos were registering random hits. I also noticed the LED on the ball trough board was lit. After close inspection, I also noticed one of the IDC connectors (I believe it's the receiving board) had been hacked. I reseated the connectors, the LED turned off, and the game started working better . . . almost.

The game was constantly launching balls to the subway, then to the right VUK, then returning to the flippers. Checked the switch test again, and all optos were closed except for the one the feeds the right cannon. Reseated the trough connectors again, left the games in switch test for 20 minutes, and had no more opto issues.

I'll replace the IDC with a Molex connector and things should be back to normal.

#20 6 years ago

JPS

JohnS

Pinside member

Mesa, AZ

8y 19,150 53 1

There is a regulated 12V and unregulated 12V supply. The unregulated 12V is used by the optos and cannons. In test mode the unregulated 12V should be well above 12V, more like 13.1-13.4V (on mine). During a game the voltage will fluctuate. You can hook your voltmeter to the test point (TP1) and ground (TP5) and monitor it during a game. When cannon is moving it will drop. If it drops too low below 12V you will have random opto switch triggers causing game play problems especially if the optos are old/original. For reference, in test mode with a cannon rotating mine drops to 12.7-12.8V.

A low unregulated 12V is usually a problem with the corresponding bridge rectifier (BR5) or capacitor (C30).

When I first got my game, I had a bad bridge rectifier BR5 (working as a half-bridge) and my unregulated 12V was around 12.2, and it dropped to 11.7V with a cannon rotating.

2 weeks later

#21 6 years ago

SFV

Hammerhead

Pinside member

Quoted from JohnS:
There is a regulated 12V and unregulated 12V supply. The unregulated 12V is used by the optos and cannons. In test mode the unregulated 12V should be well above 12V, more like 13.1-13.4V (on mine). During a game the voltage will fluctuate. You can hook your voltmeter to the test point (TP1) and ground (TP5) and monitor it during a game. When cannon is moving it will drop. If it drops too low below 12V you will have random opto switch triggers causing game play problems especially if the optos are old/original. For reference, in test mode with a cannon rotating mine drops to 12.7-12.8V.
A low unregulated 12V is usually a problem with the corresponding bridge rectifier (BR5) or capacitor (C30).
When I first got my game, I had a bad bridge rectifier BR5 (working as a half-bridge) and my unregulated 12V was around 12.2, and it dropped to 11.7V with a cannon rotating.

I just checked in test mode with the cannons operating, one lead to ground braid, one lead to TP1, voltage was a steady 12.08V, didn't see any signs of a voltage drop.

#22 6 years ago

SFV

Hammerhead

Pinside member

OP
Quoted from Hammerhead:
I just checked in test mode with the cannons operating, one lead to ground braid, one lead to TP1, voltage was a steady 12.08V, didn't see any signs of a voltage drop.

On top of the other "berzerkiness", now I get an error message for a ground fault for switch Row 5?

#23 6 years ago

SFV

Hammerhead

Pinside member

Quoted from thewool:
Hi there LTG. By chance I was fitting some new speakers and sub into my STTNG last night. I powered her back on and starting getting the odd behavior in game that I described (everything going off at once). I left the switch matrix on and captured on video what happens:
» Vimeo video
Fast forward to about 1 minute to see the action, it looks like all the optos activating. Just after the video stopped the same thing happened again and a most of the third row from the left disappeared.
Hope I'm not hijacking this thread buy maybe the OP is having the same problem. Hammerhead have you checked out your switch matrix during your issue?

I like your Romulan warbird mod, how did you do it? I have the Halmark ornament ready to go, just don't know how to go about it.

2 months later

#24 6 years ago

SFV

Hammerhead

Pinside member

It's been a while since I posted here. Berzerkiness is gone, magically, but the under playfield diverter to the right cannon is not working. The coil itself works in test mode, but the ball always goes to the left cannon, so when the game powers up, it constantly launches balls, which go to the left cannon, and then get ejected out. Rinse and repeat.

Perhaps it's this eddy sensor that's the root of all my issues? Hopefully just dirty as opposed to bad.

#25 6 years ago

JON

Schwaggs

Gameroom Mods

10y 105K 4,760 10

Try re-seating the switch matrix connector on the Opto 16 board (top in this picture). If that resolves it, you may want to replace the IDC connector with a molex crimp type connector. I resolved issues with this connector and the trough connector on many games by applying a VERY thin layer of dielectric grease to the header pins.

pasted_image (resized).png

4 weeks later

#26 6 years ago

SFV

Hammerhead

Pinside member