Typically is you have the same voltage on both sides of a current limiting resistor, it means there is no current flow usually caused by an open circuit. The most likely cause of this is a broken thru hole at one of the transition points, or a broken run. I would have to look a little at this circuit in more detail to provide more circuit specific information, like I mentioned previously, a problem in this area will effect half the board, not one just one opto; this is easy to verify on he bench.

For bench testing this, you may want to also tie your 2 column pulses (J5-9 and J5-10) to a source (12V, gnd, or a pulse), as leaving these open can cause erroneous readings; i usually use the pulse function of my logic probe for this when working on the bench.

Before I replaced U2 it was just the one opto and there was clearly a problem with the output on it. However after replacing it now everything is messed up.

From my understanding I should get 12v on both sides of R59 unless something is shorted to ground in which case the voltage drops due to resistance. So the low voltage reading indicate there is a short to ground (or so I've been told). But I've been all over that circuit and can't find a short anywhere. There isn't much left with 3 of the LM339's removed from the board.

I found the short. There was a micro trace that passed by one of the legs on U2. When I desoldered U2 a microscopic amount of solder mask was removed and exposed the trace. Not enough to actually tone out as a short so it made it hard to trace. I basically put 12v on R59 bypassing it and looked around for 12v where there shouldn't be any. Found it at R18 and R22.

Removing the socket row proved to be much harder than removing the chip. Wasn't an easy task even with my Hakko 301. Ended up destroying 2 pads unfortunately. Put some jumper wires on so should be good now though. I think it might be fixed now but won't know for sure until it's in the game.

gotcha, the voltage is around 12V, the readings on both sides are similar as the voltage drop across the resistors is only 1.7V this was my fault as I assumed you had the same voltage on both sides of the resistor which would be an open circuit.

So finally got round to looking at my Star Trek after about 4 months of it being out of action

It was continually launching balls then ejecting from the left

Basically it was nothing more than a fuse to the underplayfield diverters

In fairness I’ve previously had long periods of not playing through the years but absolutely loving this pin again

So glad I kept it

Oh and I’ve turned off the cinematic pin sound too and returned to the original soundtrack . Much prefer on reflection

Looks great! Where did you get those custom instruction cards on the apron?

Someone must have sold those years ago as my machine had the same ones when I purchased it in 2004.

I found this website has free downloadable instruction cards, including the set on the machine in the picture. I found that set in the file that has "Matched Set in Zip Format" in the title. I think I might print them out for my machine too. They look pretty good.

http://www.pinballrebel.com/game/pins/instruction/

We have a switch 16 down, here!

Switch 16, left return lane. I think switch 17 is its brother.

What is that? Is it some type of magnetic detection device? There's no visible switch or opto so it's new to me.

It's interesting...

Those are both Eddy-current boards / switches. You probably just need to adjust it by turning the pot on the boards until the LED comes on and then back until it just goes off. Then run a ball over the inlane and make sure the led lights and the switch registers in test when it passes over the board.

Thanks for the info! Say, where is the board located? There are pots eh? I had no idea.

How do you get the trigger mechanism in ST:TNG to fully pop out? Mine doesn't come back out fully on it's own and you have to manually push the trigger mechanism you squeeze to launch the ball out in order to get the trigger to unpull. This is problematic in modes like "Battle Simulation". Does anybody know an easy way to fix this? If it involves opening the phaser up, how/where do I find a proper bit to open it?

Thanks!

Loving the game!

I had the same problem a few ago. I unbolted the "phaser" shooter handle from the cab and took the handle apart. Mine had some old grease or oil that I cleaned of the rod and springs I then relubed everything with some very light oil where there was metal on metal contact and kept it away from the switch. Reassembled and it works great! Did not do much for my high scores though

If I’m understanding the problem correctly, you’re pulling the trigger on the gun to launch a ball up the playfield or to fire a cannon, and the trigger doesn’t spring back for the next shot? I had that happen on mine a couple months ago. The small spring inside the gun was broken. Just had to remove the gun from the cabinet and open it up to find the issue (in this case the broken spring). The gun is easy to remove, take apart, put back together, and re-attach to the cabinet. I’m an accountant with no mechanical skill and was able to do it. .

Only requires the correct size nut driver or screwdriver to remove the gun from the cabinet and then take the gun apart. Once you open the gun to check what’s going on with yours you’ll see it’s a pretty simple mechanism. I ordered a replacement spring online from Planetary Pinball. It was called a friction spring and was labeled as being for STTNG. Hope this helps.

Just to clarify, you were able to remove and disassemble the gun with only screwdrivers and hex drivers? There was no need to remove the screws that take a weird nut on the side of the phaser?

You do have to remove the four T10 secure torx screws (sometimes called security star) holding the two halves together.

ALL of the parts for the gun handle:

A-14747 gun handle assy 1
21-6688-L handle-gun 1
21-6688-R handle-gun 1
10-304 spring-friction 1
A-14712 bushing fire pin assy 1
02-4550 collar 1
02-4551 bushing 1
02-4558 pin firing 1
A-14694 trigger assy 1
02-4545 hub-trigger 1
02-4546 fastner-button head 1
02-4547 "fastner-button head 1/2""" 3
4702-00014-00B lw 1/4-20internal tooth-black 4
4702-00013-00B lw #10 internal tooth-black 4
4010-01174-06 ms 10-32x3/8 t-r bttn head 4
4006-01003-06 ms 6-32X3/8 p-ph-s 2
4700-00129-00B fw .203x.468x.030 black 4
02-4588 tubing-spring stop 1

is it normal On start-up and first game, to cycle all 6 balls before allowing a game to start. If not what is the most likely cause?

No, it should stage 3 balls, one in each of the three VUKs. likely cause ... subway diverter or opto malfunction.

They are mounted under the playfield right where an actual inlane switch would be.

Sweet. Thanks for the info!

In order to fix the spring, all I needed was the 3/8 (I think) nut driver and a screwdriver. I was at work when I responded earlier, but I just got home and saw your question so I re-created my work to check myself. I took a few pictures to show it also. First, remove the 4 nuts & bolts that are holding the gun on the cabinet. Then you'll see a round piece held in by two screws. When you unscrew them and remove that piece, you get access to the cylinder (probably not the right technical name for it though) that the trigger pushes forward to fire. The cylinder has a spacer type piece on it along with the spring that pushes it back to fire again. If your issue is just with one of those pieces then you can get at it with the nut driver & screwdriver. If there's a deeper issue then you need to have the security tool to open the gun in half. I don't have that tool and I found my issue was the broken spring so I didn't have to try to open the gun assembly into it's halves. I don't know what else might be in there other than the trigger. Might be worth opening it up just this far to check the spring and cylinder to see if those are the problem though. Here are pics I just snapped as I took it apart so you can see what you can get at without the security tool:

STTNG Gun 1 (resized).jpg

STTNG Gun 2 (resized).jpg

STTNG Gun 3 (resized).jpg

STTNG Gun 4 (resized).jpg

Should an opto be replaced if it’s an orangish/brown color?

Lots of stuff going on here. It’s not launching any balls at all right now. Any ideas? (I removed the electrical tape being used to insulate the twisted wires)

It looks like my J120/121 are both toast too.

995BBD00-3CF2-4D32-B037-BC2C0089FA9D (resized).jpeg

2CDDEAA6-1118-4210-96DC-1CAD30264EE1 (resized).jpeg

B578A090-E1D6-4C6B-AA30-B7C26CAAB148 (resized).jpeg

That soldering and wire hack work...

J120/121 are GI power, and those need to be redone with new headers/connectors, they're burnt, but not your ball launch issue.

The wiring to your eject coil and trough opto board is suspect AF, I would redo it all correctly... but at minimum, flow solder on all the wire connections and make sure it's actually wired properly. The white/yellow wire running to that coil doesn't look well connected.

Yeah, I know, it’s terrible. It’s just 4 more things on a long list of things.

Can anyone recommend someone that can solder new headers to the board? Also noticed this U13 chip has some heat marks behind it.

Not even sure where to start on the wiring.

836D2A94-0005-44DC-BA89-5CE74FF60BAB (resized).jpeg

FEE58931-E2AE-463D-8A42-01F1289FA636 (resized).jpeg

I can help you out with the headers. Shoot me a PM if you'd like.

Looks like someone ripped out a thru hole and tore a run on this repair, sad on such a good looking board ... at least they cleaned the board afterwards.

If you are looking for a board guy, I always recommend me

Thanks! I used your pictures as a guide for fixing mine. I didn't have the correct spring but found that one out of a G2 inkgel pin, cut it in half with snippers, and it works just fine. I may or may not replace mine with the "correct" part next time I make an order but it got the game up and playing again. Cleaning the firing mechanism on this thing felt oddly like scraping the carbon off of a M-16.
Blaster (resized).jpg

Cue flashback sequence..

M-16 firing pin... This one's clean.

M-16 (resized).png

Thanks! It worked.

So, what does the LED do on the board?

I just flicked it and the light came on, then off. But my right one (which works), it currently red.

Assuming you have the original boards, the LED turn on whenever a metal object is detected in the sensors field.

Depends where it's located, if its hard to get at and you currently have access to it, you should replace it; however if it's easy to get to and its working...leave it alone. I have many optos like this in my machine that have been working fine for years after my restoration.

Went through the various flipper tests today. The left flipper doesn’t move during the “hold” test. What could be the cause?

It seems to work fine besides the hold test.

Hodl coil might not have enough oomph to move the flipper. Can it hold it up if you manually move it?

I'm finalizing fixing up my machine and am down to the last 2 issues... ball ejector and flipper strength.

1. Does anyone have any issues with the ball eject shooting the ball into the shooter lane not always throwing the ball to the top?

I am in the process of fixing the last few items on my machine and the ball eject does not always shoot the ball all the way into the shooter lane, causing the ball to repeatedly try to go into the shooter lane and stop play for a while. The funny thing is that it works 90% of the time, but when it fails it fails repeatedly stopping play. The machine came with a replacement ball ejector VUK new in the bag, but I don't want to use it if it's a simple fix like bending something. If there is something else I should do let me know, otherwise I'll just replace the whole coil.

2. How hard is it to shoot the warp ramp on the left? The ball doesn't always go up all the way. I have a rebuild kit but am hesitant to install it unless it really needs it as I've never done one and don't want to break anything. Should the ball go up the ramp all the way more than 50% of the time or is that pretty normal.

Thanks and loving the machine.

I’m not sure about the ramp question, but I’ve had to adjust my VUK. First the ball would very often come out and bounce straight off the far wall and go back down the hole to the VUK. There’s a metal side tab/guide at the hole opening and I bent it slightly so the ball would get deflected a bit toward the front of the machine. That kept it from bouncing back down the hole. The trade off has been that, like what you’re experiencing, there are times now when it hits that tab enough to prevent it from coming out on the first (or even second) attempt. I’m going to try making another slight adjustment to bend it the other direction and see if I can find the happy medium.

Just curious... what did you use to bend the tab with. Mine is a pretty stout piece of metal.

Thanks!

I just used pliers. It wasn’t the easiest to bend but I was able to get it enough. It only took a very little bit of bend on the edge of it to make a difference. Yours could be different depending on where and how the ball is hitting as it’s kicked up. Might be worth taking a slow motion video of it so you can get a good look at how you might need to adjust yours.

The coil mounting holes in the original VUK were oval (slotted) so that the positioning can be adjusted, if firing too hard, move it down a little and if too weak move it up a little. there is only a little wiggle room here, but after a couple position adjustments mine works flawlessly (original coil).

Rebuilding a flipper is one of the easiest things to do, I would just do it; you dont even have to desolder the coil, just let it hang by the wires.

My father is in town today; and the damn STNG wouldn't work. I've done no debug yet...
The game resets withing 5mins... and the flippers reset the game in milliseconds of flipping either flipper.
My gut tells me that one of the power supplies is low. If anyone has any quick thought; I'm open to it.

Any chance your line voltage into the game is low, STTNG definitely does not like it if it is! Otherwise yes, I would suspect you have a power supply issue.

Quick fix: slap a Khar power fix board in it

Shotgun fix: Test/replace BRs and replace caps on the power driver board.

Spend a lot of time fix: follow PinWiki steps for game resets.

FWIW, my STTNG went all kinda stupid resets, weak, blah, weirdness. I had already done one failed BR, tested them all, still good, so I just replaced the 5 big caps. It plays like a new game. LEDs are bright, flippers are awesome powerful I can actually hit ramps now...plays like a new game. But be skilled with board rework or you risk pulling the through holes when removing the caps and having to solder stitch fix them.

The line voltage could be low; but the reality it is the same location it's been in for over a decade.
I'll methodically go thru the game checking for ripple and DC voltage on the game before moving on to more shot gunny type things.
IIRC; I don't think I've had to do any power supply work on this game so it's really due.