(Topic ID: 46173)

STTNG: Auto launch always puts 2 balls into play after Final Frontier

By tsool

6 years ago

Topic Stats

  • 15 posts
  • 9 Pinsiders participating
  • Latest reply 6 years ago by 1967Firebird
  • Topic is favorited by 3 Pinsiders


Linked Games

#1 6 years ago

Hi all,

the caption basically says it all. The machine works perfectly, but if I lose the ball after Final Frontier the auto launcher always puts two balls into play. It never happens before that.

Whenever I reach Final Frontier and the last ball is lost, the trough pushes ball number one no launch, then second ball gets into position behind the first ball and then the auto launch fires. At that point the first ball sometimes does not get the necessary force to go over the ramp into play. Auto launch is repeated until both balls are in play. The downside: as soon as I lose one of the balls, the game is over for the machine (which is correct), but yet again, two balls are launched. So for me, the game is basically over after Final Frontier. I have no idea how to debug this, because as soon as the game restart is normal until Final Frontier starts.

Does any long-time TNG owner have an idea?


#2 6 years ago

Check your last opto in the ball trough. Sometimes during a long game, the resistors heat up and the board will bend slighlty causing a missalignment of the last opto. Just a thought since its doing it only after FF and Ive had similar issues with that being the cause. Mine got so bad once it snapped the resistor off from tension.

#3 6 years ago

Agreed on the opto-boards on the ball-through.

Best is to remove them both (not that hard to do) check for dirt on the opto's, solder joints (should be bright and crisp looking), and the header-pins on the boards.
Also look at the switch-edge test if those optos all register.

#4 6 years ago

remove the opto emiter board LEDs from the 3 screws and test with the mobile phone camera you should see the infra red working leds change the not lighting LED

sometime the resistors end which power emiter LED will crack due to vibration !

#5 6 years ago

Thanks, all. Will try my best!

#6 6 years ago

I checked. It is TROUGH RL 5 that does not show up in the switch test if there are 5 balls in the trough. Basically, if I do a switch test all switches show up, most of them very quickly, but the last one is always yielding the number of balls in the trough.

E.g. 1 ball, switch test shows TROUGH RL 1, 2 balls TROUGH RL 2... 6 balls TROUGH RL 6, but it never shows TROUGH RL 5.

Now I need to understand how the switches work in order to decide if something is broken or not. Does it work like a sensor barrier that the beam is cut when the switch is "on"?

#7 6 years ago

Yes, when the machine is on there is an light-beam from the white-opto to the blue receiver.
It registers if that beam gets broken.

Normaly first thing to suspect is the white sender opto, but since it is in the ball through it can be cracked solder on either white or blue one, from vibration. Or actualy a broken opto.

First try to reflow the solder joints, before replacing.

#8 6 years ago
Quoted from tsool:

Now I need to understand how the switches work in order to decide if something is broken or not. Does it work like a sensor barrier that the beam is cut when the switch is "on"?

That is correct. Invisible beam that completes the circuit, when a ball rolls in front, breaks the circuit and activates the switch. First thing to do is clean switch lenses with a q-tip and windex. Then put in switch edge test mode and try to activate trough switch 5. Also, make sure the wires to the switches themselves are intact.

Edit - the Q-tip trick will most likely not be applicable here since the switch is not registering vs always registering. As others have stated, check solder and wiring to the optos, traces, ect. Good places to start.

#9 6 years ago
Quoted from tsool:

Now I need to understand how the switches work in order to decide if something is broken or not. Does it work like a sensor barrier that the beam is cut when the switch is "on"?

Exactly right - most likely the IR emitter for that switch is not working. Easy to test using your cellphone or digital camera. It could be a broken trace, resistor, or bad emitter. Your multimeter will show you the way. Those trough boards have a hard life due to the heat and constant vibration!

#10 6 years ago

Is there anywhere where I can read up how to use my multimeter? I have a basic knowledge of electrical engineering, but I do not know how to measure resistors and what is to be expected.

Furthermore, I read a couple of threads that say to use cellphone or digital camera. I have also no idea how to test and what to test with that I understand that I can move something between the beam to see that it works, but why would I use my cell phone?!

Do I need to order two new trough boards if I cannot fix it myself?

#11 6 years ago

Take it one step at a time, and don't think of problems when they are not there ... yet
(so wait on the new boards, first try to fix them )

With the digital camera you can see the infrared beam going from emitter to receiver, you can't see them with only your eyes.

For multimeter use, take a look at pinrepair.com and the pinwiki.com, there you will find components to measures and what to do, and how your meter can be read.

#12 6 years ago

As Bigdaddy suggested, your first port off call should be in test mode using single switch test. As you cover each opto, you will see a cross come up on the screen if it's working. It's a nice easy test so worth doing first.

#13 6 years ago
Quoted from bigdaddy07:

That is correct. Invisible beam that completes the circuit

If you have a camera on your cell phone, you can "see" this beam on the screen... it looks blue... IIRC

Well the emitter will be blue. You can't actually see the beam...


#14 6 years ago

Check out my video which should help.

#15 6 years ago
Quoted from SaminVA:

Check out my video which should help.
» YouTube video

That was a great video thanks!

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