(Topic ID: 87066)

STTNG Trough Gremlins


By visi0n

5 years ago



Topic Stats

  • 10 posts
  • 8 Pinsiders participating
  • Latest reply 5 years ago by gcp
  • Topic is favorited by 1 Pinsider

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#1 5 years ago

So, I finally found my STTNG Pin that I've wanted for three forevers. I'm excited, it looks nice but it has some gremlins that I'm trying to work out.

On game start, the machine wasn't always launching three balls to the playfield. Often, it would launch one. sometimes, it would launch 3 and one would return from the left VUK area and then drain. Usually, it wouldn't launch three, only two.

Then, during game play, the machine would kick two balls in during play. It was confused by the ball-count in the trough, it seemed. Searching these amazing forums and the internet at a whole, the prevailing bad guy appears to be the trough IR board. So, I put the machine in switch test and pulled the three screws off the trough board.

I looked at it through a camera and all of the IR LED's appeared to be on. So, I shone one of the led's down each hole to check the receiver. All switches cycled on the switch test. Then, I notice all of the sudden, two of the visible LED's on that opto board are no longer on and that board (A GLM board, older one with 1S-X9T-07 printed on it)

So, I do the camera check and now D1, D2, D3 are no longer transmitting. 4,5,6,7 are.

So, I think "strange"/"maybe I fried it somehow?" and go order a new opto and receiver from Marco, which arrived today.

Still touching it with the static bag, I plug it in and notice that on this (supposed to be new..) board (with the older design, large resistors, etc) that LED 6 is not on. So, I sort of mark it up as terrible luck and order another one. (That is on the way, this time another GLM board)

In the process, with this new board installed that works minus LED 6, I start the game and notice the trough solenoid no longer fires, even under test / clr out all balls. But that worked before all this started.

Connection appears to be good. Seems like I'm chasing ghosts. Will the Trough Solenoid fail to fire at all, with a faulty trough board, even in Tests? Didn't seem likely to me but hey, whatever - I'm chasing ghosts, bad-mojo here.

So, I test the fuses on the power /io board. They seem fine. This is the part where I'm afraid you tell me to start by replacing Q54. So, totally hoping there is a fix that doesn't involve me pulling the IO Board and yanking Transistors and other neighboring components. I have such poor luck in that area.

I should mention that, right now, with this newer board installed, if I close the coin door and go to clr-out-balls, the coil on the right bottom subway pops every couple seconds, but nothing else.

Thanks in advance to the awesome Pinsider Community for any help/ advice fellow war stories

#2 5 years ago

I chased this one with my STTNG at first, too. It's a good system when it works. Getting it to working is the trick!

A few things to consider in your diagnosis, that I didn't get from your description:

1. The solder joints on both the opto receiver board and the opto transmitter board crack over time, probably because of the balls falling into it and the slam from the solenoid. I had to reflow all the pads on the big resistors on both boards. Several were cracked but not visible cracks. Under 10x magnification I could see the pins moving around in the hole when I wiggled them. But, that doesn't explain your new board problem, unless you only replaced half.

2. I had some very small divots in the trough itself where the balls sat. This sometimes would hold a ball in position after the one downhill from it rolled towards the lift solenoid. This is tremendously confusing to the machine and can also make it lose track of the ball count leading to weird stuff as you described.

3. The machine only loads as many balls as it needs to at power on and between games. This can be anywhere from 0-3. That count is meaningless. However, continuous loading and ejecting is a meaningful fault. If it seems like too many are being loaded, test the under playfield divertor.

4. There are also optos in the VUK assemblies under the playfield that keep track of balls held there. They get subway grime on them quite easily, and can also fail entirely. Misreading balls there can also lead to odd behavior.

5. Super-obvious but I'll mention it anyway: the trough solenoid won't work with the door open due to the safety interlock. You knew that, I am sure, based on your mention of closing the coin door on clear out balls.

6. The trough solenoid should fire in solenoid tests. That's something fairly straighforward to chase, unlike opto problems which can be notoriously flukey.

#3 5 years ago

The 0.100-inch insulation displacement connectors on the trough boards may have issues; for example, the wires are not held firmly in the V-slots of the connector. Given that the issues appear to be popping up as movement is involved you might want to try wiggling the connector as well as the wires "punched" into the slots in the connector to see if that affects the operation when in test mode. I had to replace one of the trough board connectors on my IJ a few years back due to this issue.

#4 5 years ago

hmm.. all good stuff, thank you!

Yep, I'm closing the coin door or manually pushing the interlock pair to test the coils. Maybe in a turn of freakishness, the trough coil just died. I'll try a new one in it's place, at least to eliminate the possibility.

The receiver board seems to pass switch tests. If I take the broken tx board (the one with several LED's out) and (holding it) shine a working IR LED through each hole, the switch tests seem to cycle correctly. (Open/ Close based on the presence of the IR LED on the TX side of that hole)

I just can't believe I got a bad board from marco. First time for everything I guess.

I'm with you, I thought about the connector going into the Tx Opto based on the fact that it seemed to cut out. It's only two conductor and one was a little worse for the wear (starting to fray inside the v-connector) I re-secured it into the IDC connector with a small jewler's flat head screwdriver.

I suppose now it's that famous wait for the USPS delivery of parts to try

#5 5 years ago
Quoted from jadziedzic:

The 0.100-inch insulation displacement connectors on the trough boards may have issues; for example, the wires are not held firmly in the V-slots of the connector. Given that the issues appear to be popping up as movement is involved you might want to try wiggling the connector as well as the wires "punched" into the slots in the connector to see if that affects the operation when in test mode. I had to replace one of the trough board connectors on my IJ a few years back due to this issue.

That was my problem. I had to rebuild these connectors to get everything into reliable condition. Then never had another problem with the trough again. Also, make sure the blue resisters are all good. They tend to have bad solder joints as well.

#6 5 years ago
Quoted from visi0n:

I just can't believe I got a bad board from marco. First time for everything I guess.

They are pretty good, But that sinks .

#7 5 years ago
Quoted from RobKnapp:

They are pretty good, But that sinks .

Meh, it happens. I'm sure it wasn't their fault and I'm sure they will make it right - they always do. Like I told the dude on the phone, it's not like these were donor organs that needed to get here in time.

Here's the board that came:

photo.JPG

It's alot like the board that originally came with the machine, versus the Great Lakes Modular that had died. I liked the mini-fication and status LEDS of the GLM board that died but at least this one is probably more easily repairable... Speaking of.. Notice the missing resistor? I presume that's the issue.

I'm tempted to just run to Spectronics or Radio Shack tomorrow and try to locate that resistor and have a go at it.

Now if I can just work out why my trough coil isn't firing, I ordered a replacement - fingers crossed.

#8 5 years ago

270ohm won't be buyable at RATSHACK.
They only carry 1kohm or 100ohm in large wattages.

If you hope that the marco one can be repaired... you might want to keep in mind soldering to the pcb will likely void whatever warranty it had.

I just recently had to repair my trough boards.
The xmitter needed a new crimped on connector.
The rcver needed the same. Wiggline either caused intermittency in the switch test.

The power connections (+12/GND) seem especially problematic on both.

On my transmitter board; I had a resistor leg break ... maybe two near the package. so look for that too.

#9 5 years ago

has there been an outcome to this issue?

please update.

m.

#10 5 years ago

I have a metric buttload of ball trough resistors*; let me know if you'd like me to send you a few.

* A STTNG that a friend gave me had been sitting in storage for 10+ years - its trough was a basket case. Several resistors had broken off. They had been "repaired", glued back on with big globs of solder, which predictably became quite flaky. I ordered around a thousand of them on principle, so I would never have to wait for any or pay for shipping on them ever again. And, low cost per unit!

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