no more than a fraction of a second

Not sure I would start by grounding transistors without performing some simple diagnostic checks:
1) Have you measured your +50V on that coil, it may not have any power?
2) With the coils molex connector removed, what is the resistance reading (ohms) between the 2 purple wires (this should be around 5 ohms).
3) If the above checks out you should have 50V on the tab of the drive transistor; if not, you have a bad connection.
4) If you have 50V on the transistors tab and you put the cannon in test this voltage should drop to near zero, if it doesn't you have a control signal or Driver board issue.

I have never in my life shorted a drive transistor tab to ground in order to determine if its working ... but that's just me.

EDIT: The best way to isolate the playfield from the equation is to check resistance/continuity from the power source to the return path, in this instance the source is J107-3 and the return is J130-2. With the game off, remove both J107 and J130 from the PDB and measure between these 2 points on the connector side, if you have continuity or a resistance measurement of <8 ohms then you can safely assume the issue is NOT on the playfield. You would also want to rotate the cannon while checking this resistance, if you see any jumps in your reading this may be a sign of a bad cannon loom, if not then the loom is likely fine.

I often suggest this method of testing because people don't need to understand how to use a meter and it eliminates a whole bunch of stuff in about 35 seconds. As long as they don't leave the thing grounded for a long time or something else really stupid it's a very quick t-shooting step that has been around for many decades.

I do realize many people do this and have for a long time. I try to help folks learn some basic troubleshooting techniques so that when they have bigger problems down the road they hopefully learned something along the way.

I've ordered the bits and will give it a go, thanks.

It's more likely the impact of the "head" of the plunger smacking into the coil mounting bracket has caused a groove to form in the face of the bracket, and the head is getting jammed in the bracket; I've seen that on a few ST:TNGs. Replacing the coil mounting bracket resolves the issue, but if the foam spacer is working there's no harm in going that way.

Didn't see any grooves in the metal, but I'll check again. When the cannon plunger fully engages it makes contact and sticks to the metal bracket, the spacer just stops the plunger contacting the bracket so it can't stick to it any more!

Thanks all.

I just ran the plunger through my demagnetizer and it worked for me. Pretty common issue. Certainly not a permanent fix but adequate.

What kind of demagnetizer do you have?

Must be covid pricing now but this is what I got a while back. I've demagnetized other pinball parts too. My RFM had a magnetized up post and also the jump ramp. Worked perfect.

https://www.amazon.ca/gp/product/B00N40U4GS/ref=ppx_yo_dt_b_asin_title_o00_s00

Would one of these work?

https://www.amazon.com/dp/B00018AONE/ref=cm_sw_r_cp_apa_glt_fabc_T277AAZS3AAPRGS5Q0YJ

Screenshot_20210415-142027_Amazon Shopping (resized).jpg

You can't run the whole plunger (including the back end which is what sticks to the bracket) through that small gap.

Sure can. I have one of those.

Hey folks, I'm finding the flippers continue to be weak and inconsistent, making it very difficult to make the delta ramp shot. I've rebuilt power sections on the main power and the Fliptronics boards (previously posted here). I've rebuilt the flippers as well with the kit. Voltages seem ok, but I'm willing to measure one more time if it helps diagnosing here. I'm debating what else to look at or try.

What are your thoughts on:

-replacing Fliptronics with a repro? maybe the rest of the ics are tired and not behaving well?

-replacing the 11629 coils with 17636? - note here that the bottom left is a 17636, the two right coils are 11629s; I was tempted to swap the delta ramp flipper with the bottom left to see if there'd be a difference

-when I rebuilt the flippers the kit didn't bring the flipper bushings - they're not floating around but its not perfectly tight, wondering if this could be causing a weak feel.

-have the trough boards ever caused problems for flipper behavior? They've been switching fine in test but I did notice that one of the boards have been replaced and the other worked on by previous owners. Toying with idea of getting reproductions for this too.

Thanks!

A low 12v to the flipper optos(or dirty optos) will cause weak flippers.

Yep, and a crappy opto diverter will also cause weak flippers so if you don't have the black diverters with the spring on them consider swapping those out too.

There really isn't such a thing... If the board is working; it's fine. I wouldn't replace a known good original board for a repo; no matter the cost.
As others have stated; your problems are either voltage related, mechanical, or bad soldering. Optos wouldn't cause a weak flipper; Optos are either on - or off.

Is your game jumpered properly for the voltage at your wall?

Dirty opto can indeed cause a weak flipper.

Q-tip the U shaped opto with some cleaner and it may improve your flipper action.

It seems everytime you tell someone with a WPC game that a dirty opto or weak interruptor can cause weak flippers someone else, often times people that have been in the hobby a long time will disagree with you but it's been proven over and over again that both of these are potential causes. I don't have an o-scope anymore to put on the signal line to the drive transistor to figure out why this is so but it's definitely a thing.

Yep comes up every time. Leaf switches are on or off. Optos are run through transistors which unfortunately aren't really switches even though modern electronics treat them like they are. They are more like a tap or a valve. How much light the receiver LED gets does affect how well the system grounds out the coil to provide the flipping action. It's a system based on 0 and 1 (GND & +5v) but partial blockage or dirty optos gives voltages somewhere in between which causes poor response/power.

Makes sure the optos are clean, make sure you have the black plastic on the flipper boards and not the white one, and make sure when you press the flipper button that the plastic actually pushes clear of the opto and you don't get partial blockage.

OK Star Trek people! Here is the perfect video background for any game room. Version 7 of the Star Trek Pinball Experience LCARS interface. 16x9 1080 HD for 90 minutes.
Here is the full resolution 16x9 version 7 LCARS
I didn't create the artwork or animation, I have just assembled this great work into a single location.
Thank you to all the artists, animators and fans who make wonderful art.

I’ve never believed this theory. The opto feeds a signal to the CPU (via comparators, etc), and the CPU activates the flipper coil. Maybe someone can change my mind, but I doubt it. =)

In the way these are used in the circuits, they cannot operate as a analog source

Y'all can believe whatever you like, but saying dirty optos cause weak flippers, is a modern snake oil myth

I'll give it a shot but you have to consider more factors than just the flipper optos themselves and realize that there are likely additional components in the mix that are also working in a degraded state.

If the optos are age degraded and dirty enough that the amount of light received by the phototransistor is barely enough to cause the transistor to conduct you can start seeing issues with the stability of the "on signal" from the dirty optos when combined with other factors that can cause a momentary decrease in the 12V source used for the IR LED making the photo transistor turn off at the moment the flipper coil draws current; if this occurs, it would result in a PWM effect to the drive transistor on the Fliptonics board as the power to the coil would be temporarily removed than reapplied.

Dirty Optos?
With a machine which functions on the reliability of the optos...replace all of them. Not doing so is like keeping the original spark plugs on a 27 year old car.
At some point, on this top rated classic machine, optos are going to get old. Instead of trouble-shooting the optos one at a time, replacement is a solid choice.
On the new Stern machines, I believe they have actually colored them, so you can see if they are on with your eyes.

Just an opinion.

Some of the pinball mod people might already know about this SUPER COOL item.
Trigger controlled leds from switches or coils on the playfield. Certainly this is a MUST to look into.
Enjoy the video:

When it happens on your game and you fix it by cleaning the optos or replacing the diverter you'll believe it.

I’ve owned WPC games for over 20 years and never have run into this. The only logical theory is what Pin_Guy said. However, I would expect that the software would compensate for “blips” in the opto signal (debouncing the input).

If I intend to keep a game, I usually overhaul much of the electronics and electrical systems. Maybe that’s why I’ve never seen this...

100% agree. And if you only replace the transmitter/receiver LEDs, it’s cheap too. I replaced almost every opto pair on my machine. Doing the same on a Stern Nascar in the sake of reliability.

I've owned more cars and trucks than I can count from multiple manufacturers for over 30 years and have never had a transmission go out so therefore transmissions never fail, cargument!!

Yeah, but there’s a logical explanation as to why transmissions fail. It’s largely mechanical.

The flipper optos are either on or off. It’s digital. So at best, when the flipper activates, the opto power has a very momentary drop. But even that seems odd as the flipper voltage isn’t the same as the opto voltage. And I’m sure there’s a capacitor involved with the opto voltage rectifier circuit. And one would think that the software would compensate for the momentary drop?

I guess something happens. Just glad it doesn’t happen on my games!

True, but that's the same as saying hitting both flipper buttons at the same time wont cause a WPC machines to reset from low 5V on the CPU board ... but it happens.

There are just lots of variables.

There is no software to take this into consideration as all of the working life of the electronics far exceeded the lifespan of a pinball machine. As well built as they are, they were never designed to function for 10+ years.

Are the flippers always weak or do they get weak as the game goes on? Do the coils feel really hot when they’re weak? A common problem of weak flippers is the flipper opto boards. If they’re intermittent they cause they primary coil to fire when the flipper is up and the hold coil is supposed to be on. Primary coil gets hot and weak. The whole reason for having two coils is to not overheat the main coil.
Go into switch test and hold the flipper buttons in and see if you get flipper switches firing.

That's not quite true.

Optos are not digital. They are analog.
If you look at the symbol for a photo transistor (the receiver of the opto pair); it's clearly a transistor. Meaning the transistor conducts more or less by the amount of Light received times a "beta gain" just like a normal transistor. I think in most cases the gain is sufficient to make it "digital" on/off... but there is a point at which the photo transistor will become digital in nature. That said if you could directly control the transmission rate with enough fine grain control - the analog nature of the transistor would be obvious.

So; the argument many make is that if the transistor itself is analog; then it's an analog system... which is wrong.

The driver/detection circuitry used by these systems is to decode the amount of light received is digital in nature. Meaning; the comparators of the circuitry convert an analog system to a digital domain. that said; you can never convince people to reality... and just have to let them believe the snake oil will work.

I'm sure there are hundreds of different types of infrared diodes and photo transistors. The ones used on garage doors work across 10 or 12 feet, on Brams Dracula mist ball they work 18 or 20 something inches apart.

I previously repaired letter mail processing machines with over 200 pairs of optical couplers (we called them light barriers) on each machine. Although not exactly like the ones on pinball machines they shared many similarities, except these were 2 or 3 inches apart.

These got covered with a very thick layer of paper dust after only a few hours of machine run time. Some of the barriers worked with many days without cleaning, even with a thick coating of dust.

I did replace some but that was with machines that ran over 16 hours a day for over 18 years. It's just something to think about.

Understood on the optos being analog. It's interesting that in Whitestar, the sender/receivers are the same LED. I'm not sure if they are special LEDs, or an "normal" LED will produce voltage when flooded with light.

But yeah, after the comparator, it's all digital.

Pin_Guy does make a good point about the 5V drop from the flippers. I guess the same could happen with the LED DC power supply. Although, I'd think you'd see random opto closures when solenoids are activated if the opto DC voltage was dropping.

It's all kinda irrelevant to me, I suppose. I usually rebuild my WPC games electronically. I kinda wish I had an old WPC basket case to work on. Right now my basket case is Nascar, although I'm through 90% of the electrical gremlins on that game.

yeah; not sure.
That said; there is some empirical evidence that LEDS can be used as photodiodes.
I'm sure that google has a bunch of pages with accurate data - too lazy to go do a search to be honest.
I did read part of a hackaday article last night which was based upon a project that was using a LED as a darkness detector; so - it's certainly possible based upon data point.

HI Eric - can you let me know which monitor you used for this build? I have a spare raspberry pie and this looks like a great usage!

I use 3 different ones in the machine.

(2) LCARS and Live Camera monitors:
fosa 1080P IPS 60fps 3.5 inch HDMI LCD Screen Display for Raspberry Pi 3 Mode B+,3 Mode B, Pi 2 Model B, Pi Model B+, Pi Model A+ with Black Acrylic Protective Case

(1) Media Playback Screen
4.3inch HDMI LCD 800x480 IPS Capacitive Touch Screen HDMI Interface Support All Version Raspberry Pi 4B/3B+/3B/2B/Zero/Zero W/Zero WH,Jetson Nano BB Black Banana Pi Windows 10/8.1/8/7

(2) Cannon Cam POVs
I think the cannon displays are changing so I will wait on recommending those.

61M7S9vvoOL._AC_SL1001_ (resized).jpg61jw6DxwRsL._AC_SL1001_ (resized).jpg710CnwNDNNL._AC_SL1234_ (resized).jpg71HwOYcUC3L._AC_SL1500_ (resized).jpg

DSC02775 (resized).JPGDSC02807 (resized).jpg

00013 (resized).jpg

Very happy to have just joined the club!

My game is missing the Romulan ship in the upper left corner.

Anyone have an extra laying around or one that you’ve replaced with a modded version? I’d love to buy it from you if so.

It is common to replace with a Hallmark rBOP.
I have done it to my machine and have an extra... posted here somewhere but the image search is gone due to what I assume is a result of bandwidth due to the datacenter fire.

Anyway; the original mod is here:
https://pinside.com/pinball/forum/topic/sttng-owners-club/page/52#post-4753118

My mod here:
https://pinside.com/pinball/forum/topic/sttng-owners-club/page/49#post-4584293
If you are interested in this ship for your game - let me know. Given the custom paint job; it won't be inexpensive.

Congratulations!

I have a couple modded ones on a shelf, first link from Zitt, these aren't custom painted but are hand wired so these are also not cheap....nothing in pinball ever is.

PM me if interested.

Eric_Manuel - beautiful machine! This LCD screen in front of the wireform never gets nailed? I hit this wireform ramp all the time with air balls.

screen (resized).PNG

I'm not going to spend a too much time trying to convince you and others of what I know to be true, having seen it many times in person on my own and other's games. However "snake oil" insinuates I'm trying to sell something at another's expense, which certainly isn't the case, I'm not offended or upset but I'll just share some ideas. When my STTNG had a weak left flipper many, many years ago a local guru/friend of mine mentioned the flipper optos, sure enough it had the white, worn-out diverters and no return spring, I swapped the opto boards around, problem stayed on the left side, I replaced the diverter and added the spring, bingo - perfect left flipper. I won't bore you with all my medicine-man experiences since then but I've personally or remotely fixed many other fliptronics games with the same issue in the last 20 years. Here's another one for the "they are either on or off" idea: why can a game test an opto perfectly in test mode but randomly trigger it during a game but that can't be true of the flipper opto? Case in point: Pinball Magic during a game would rather consistently think a ball was in the Genie scoop when it wasn't, nothing in test mode, banging on the game etc. would trigger it but a good cleaning later and the problem is gone.

bobukcat,
As an electrical engineer with a firm understanding of working circuit theory; your anecdotes are a unfounded myth.
You can continue to believe them; but, reality it's just not true.

You've heard of mechanical stress; right? you know that optos' die inside the package are connected by tiny wisker wires that could be bad inside the package.
You've heard of bad solder joints; right?

I'm not denying your experience - just denying that optos are the cause of "weak flippers". They cannot contribute to "weak flippers" in a traditional analog sense. If "weakness" is fixed by an opto swap - it's likely a whole slew of different reasons not directly attributed to the optos themselves (alignment, mechanical, etc).

By all means replace them if they are suspect; but they should be a primary swap reason for "weak flippers".

On STNG; replacing the optos is generally a great idea if they original optos are suspected in game. The mid 90's epoxy in the LED lense has likely yellowed due AGE and IR contamination... what should be blue is tea brown. This leads to IR light transmission issues which leads to phantom opto triggers which leads to game errors and multiballs. I didn't not have any luck getting my personal game stable until I systematically went thru and replaced all Opto pairs in the game.
(Note; I did not replace the optos on the flipper boards - because they didn't have the same issue)

EDIT: Nevermind.

Now I understand perfectly, engineers work in a world of known specifications where everything works a certain way all the time. The difference between a technician and an engineer is that the the technician knows whatever they are working on wouldn't be broken if the first statement was true.

I spent 5 years as an RF Engineering Technician working with some of the most brilliant RF Engineers in the country on never-done in the consumer market type stuff. I had the most amazing set of test gear on my own personal bench, well over $250K worth of HP gear back when that was real money in the early 90s and I had access to even more of it. I was just a tech but when I told one of the senior engineers that something wasn't right they listened to me intently because they knew I had been thorough of my testing and documented it. The new engineers got assigned to me initally so I could show them the differences between their theoretical or simulated designs and reality once it was built on a board with components, I think it's fair to say I have a "firm understanding of working circuit theory" but I don't really want to derail the thread any further.

Still looking for a spinner assembly. Thanks

Ok, finally, here is "The Star Trek Experience Video Wall". Ver 4.0. 90-minutes of amazing and fantastic media for any Star Trek fan. Perfect for a game room theme.
All in 1080 HD. Enjoy and please comment if you like it.