Hi all... This is for a Star Trek Pro (Stern) but likely could apply to any machine.

First off, as mentioned before, I'm a first time pin owner.

I switched out a stand up target today (switch 47, ironically Star Trek's lucky number), I believe. Now when I run the switch test, 47's fine, but two other switches in the same row are going intermittently crazy, with bursts of on/off, switches 33-36, all along the same green/orange wire...

Here's the switch chart... (Hold on, will have to rotate and embed when not in a phone)

So I desoldered the old switch 47, put a brand new one in, did my best to solder that on... Clearly I did something wrong, but I don't know how to diagnose it resolve it... I'm desperately hoping that I haven't ruined my first pin by screwing up changing a switch...

Screenshot_20200724-233346_Drive (resized).jpg

topkat - I tried to mirror what was done in other switches... Maybe I did in

trilogybeer - this sounds likely... See photo, sorry posting desperately from phone.

So if I remove the connections and solder more accurately, this may resolve?

1595648737808921879242713690864 (resized).jpg

I disconnected the switch... The other four switches are still going nuts... (Geez, I don't know what I've done)

Reconnected, didn't help, now switches 33-38 are all lighting up. First six switches in that wire row.

Thanks kindly, all. Will check it out tomorrow and update...

Two questions:

1) if I disconnected switch 47, and other switches are bursting, does that that rule out a misconnection?

2) The other thing I'm noticing is that the switches that are flipping out are all optos. Is it possible that solder got onto the exposed opto boards and is intermittently shorting them? If so, would it be visible, and would replacing those be an option?

Will check the diodes and connections on a few hours, thanks again?

Sadly, that might have just been an use with my photography... Is this the correct orientation?

20200725_090429 (resized).jpg

So all of the opto boards connections were reseated, all light up red.

Targets A & B were the ones I swapped out... So it is safe to say it's unlikely that I dripped solder onto each of those boards (?), which still leaves something I may have done to wiring...? Is this right track?

(Edited; I thought leaving opto board connected was the only one that had no issues, but no, it was still triggering switches 33/34.)
20200725_090942 (resized).jpg

Okay, I'm hoping that this helps... Switches 47 (target A above), and 49 (target B above) were the ones that I replaced.

Switches 13-14, 33-38 are firing in intermittent bursts.

Disconnecting the opto boards resolves nearly all of the firing, though 33 & 34 are still showing up as intermittently firing without them...

wiring (resized).jpg

I believe so... And just to answer an earlier question, I took these before, after and adjacent pictures of 47 and 49 as well... It was tricky because the old switches were not the same as my Stern ones, so I used the adjacent switches as a reference for what connections to make... (the installed switches had diode with front and back lugs, rather than the middle and back lugs that the new stern ones had)... Do you see anything obviously out of place that I need to correct?

Switch 47

Switch 49

trilogybeer - Okay, I just ordered a multimeter... This is very new to me. Okay, so I'm following the green/orange wire, and testing the diodes on each of the switches. I'm looking for a voltage drop of 0.5-0.8, is that correct?

eyeamred2u - I strongly suspect that solder splash may have been what happened; I just don't know what I'm looking for... Silver blotches on... anything below/nearby, at this point?

This will obviously take me a few days; if I meet with failure to figure this out on my own, is this something that an experienced on-site Pinball repair tech would be able to help narrow down?

The targets were bent off-kilter and the the faces had chipped. Not knowing how long it had been since they had been replaced (as clearly they were not the originals), I wanted to replace them and put in anti-sway brackets as well... (And for that I seem to have shorted out all of the ramp optos and center locks).

However this turns out, my thanks to everyone for your great advice and patience... Fingers crossed; will update in a few days, with thanks...

You guys are amazing. The problem was actually with the contacts in switch 49(!) and not 47, which surprised the ever loving heck out of me. I looked more closely (on your recommendations) and it did look like the soldered wire was a bit of a solder blob. Just to check, I disconnected the switch, cleaned off the connectors to 49, and all of the problems vanished...

I can't thank you all of you enough (besides by donating again to Pinside shortly) for all of your patient help!

(Will definitely practice soldering on a horizontal surface to develop some technique before I dive into vertical soldering again!)

Sadly, it looks like problem did in fact reappear, in short order... I'll have more information shortly...

Okay, so upon play, games were hitting the 100s of millions in short order, as the warp ramp switches were bursting intermittently.

A few things I've done...

1) I switched back switches 47 and 49 to the old targets, reconnecting them as they originally were. As with the new targets, the old ones still work on a switch test, and the problem remains, so the new targets themselves weren't specifically the cause.

2) Didn't see any obvious solder splash on boards/connectors underneath either of the switch locations (but to be honest, it's entirely possible that I don't know what I'm actually looking for... Was thinking small silver blobs on the tops of boards or wires, but I didn't see any.)

3) Looked for wires/lamps touching; didn't find anything either...

4) Tried following that green/orange wire, but as we head down the playfield, they snake into a nest of wires, and the only places that I follow out are to the opto boards, which, as we know are giving the problem...

5) Did some more testing on the opto boards... Here's what was able to determine (referring to the image below as a reference).

see below.
Okay, so, for reference...
Opto board 1 controls switches 13 & 14 - warp ramp entrances
Opto board 2 controls switches 33 & 34 - center lock optos
Opto board 3 controls switches 35 & 36 - warp ramp exit
Opto board 4 controls switches 37 & 38 - Both optos for right ramp.

And, as another reminder, switches in red are the ones that are firing.

Memory lane

What I found:

Plugging in all 4 triggers crazy firing of all of the switches in red above.

Plugging in opto board 4 (even by itself) triggers nearly constant firing of switches 33 & 34 (the switches controlled by opto board 2).

Moving on:
Plugging in EITHER boards 1, 2 or 3 on their own seem to be okay. At the very least there's not IMMEDIATE firing of anything.
Plugging in boards 2 and 3 together seem okay as well. I've played a bit, there doesn't seem to be random firing (yet), and gameplay seems to be okay (other than the right ramp being dead because board 4 is off).

Plugging in board 1, with either board 2 OR 3, does lead to the firing or (I believe) 33, 34, 35 & 36.

So, the problems seem to be with opto boards 1 and 4, at least that's what I'm starting to conclude... Would this seem right to all of you?

Two possible red herrings:
1) My son says that the warp ramp did rapid fire on one prior occasion BEFORE to the target swap. He figured it was just a one-time thing. Could be a symptom of a bigger problem?
2) When I had all four opto boards plugged, I did get "Center Lane Lockup: Device Malfunction" which might be unrelated, or a result of crazy firing of 33 & 34?

Is it even possible that replacing boards 1 & 4 could actually fix the problem? Or does this sound more like a wiring issue of some kind? (Has anyone ever heard of a problem with an opto board triggering switches controlled by an opto board elsewhere along the line?)

Well, sadly, the problem was not those opto boards... Replacing them didn't help... So, presumably it's a wiring problem?

Good evening! For the switches? I believe so, but just in case I was wrong I went back to the "before" pictures I took and resoldered the old switches in the same orientation. The issues persisted when 1) the new switches were connected, 2) both switches were removed altogether, and 3) after the old switches were restored...

Thanks all, for the advice! (I apologize for my recent absence; I had gotten a bit discouraged and stepped away from my pin for a bit to stem the disappointment.)

In the intervening time, I did get a multimeter and followed up the suggestions to check the diodes up the 33-38 switch line.

I found that the remaining diodes on the line (39-48) all showed similar unidirectional drops, with the exception of switch 44, which dropped all the way down near zero. I thought this was the culprit, until I realized that switch 44 is a rollover switch, and when I checked its behavior against the diodes on rollover switches 28-29, I found that the diode for this switch behaved similarly to those, which is I presume indicates that the diodes aren't the problem either (though I was hoping; sorry!)

Alright, having had some time, it looks like the game is stable when turned off, then up to any TWO opto boards are plugged in, and the machine is turned on. (My previous results had been dis- and re-connecting the opto boards while on.) So it seems like once I plug in any third opto board, those connected boards all light up...

If it's not specific to the orange/green driver line, and swapping out opto boards hasn't helped, could this have something to do with where the opto boards' respective signals get carried to?

(Oh, wanted to add: erak thanks I tried reseating the pinball trough opto cables, sadly didn't help either...)

Alrighty, this has been resolved, and I wanted to wrap this thread up. My thanks to all who offered advice, and particularly to hawkmoon77 who walked me one-on-one through a lot of testing...

In the end, it turned out that the there were two problems...

1) The main problem was likely a short. This problem ended up being inadvertantly resolved after the playfield got accidentally and heavily jolted (for reasons that are too embarassing to describe). Whatever it shook loose, I ended up being able to reconnect all 4 opto boards without too much of a problem...

...except for opto switch 13 (warp ramp entrance). On some plays it would burst on and off. Others fully on, others fully off.

With the other 6 optos on one driver line resolved, I thought it be odd for switch 13 (on another driver) to be shorted by the same problem that was on the other line... So I examined the warp ramp really closely, and saw this.

processed(7) (resized).jpeg

The opto was partially blocked by...

processed(6) (resized).jpeg

that textured translucent "sandpaper" on the side of the ramp. When the machine vibrated, the opto would [i]just[/i] manage to block, and unblock over and over. So I took an exacto knife and tweezers, and sliced around the opening, removed the offending piece, and then all was right with the world.

Thanks to hawkmoon77 who walked me through a lot of multimeter testing, and to all who gave great ideas and advice!