Hey Folks! I finally found a STTNG of my very own - I'm amazed at the complexity of this game, I've only worked on 1 EM before this.

It needs a good shop job. That said, the video / dmd is off; anyone have any ideas what it could be? The dots on the display are moving according to animations, but they're all piled towards the bottom of the DMD. I've reseated the ribbon connector and the power connector to the DMD, no change. Where should I check/focus next? Thanks!

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Thanks Tranquilize, I tried your ideas, physically tweaking things didn't show change. I checked the voltages at the DMD, the 5v and 12v were good.

Since I wasn't getting much progress I punted further investigation until I could talk to some friends about lending their DMD.

As part of going through and cleaning up the machine (it was so dusty!) I'm very happy to report that I pulled the batteries from the board to test their voltages. No leaking. I guess the system was in some sort of bad/corrupted memory state, the display started working after I replaced the batteries. Ran through the tests, replaced a pile of light bulbs.

Game is running, couple of things to do: Neutral Zone hole is worn, so finding a Cliffy for that, the left cannon is not finding home, and the top left corner is dark that I can't see much of what's going on (I'm wondering if there's a burnt bulb I missed there or it's just dark).

Alas, it did not last. The display ran fine for a few hours, and then went scrambled towards the bottom again. Friend of mine has lent me a TZ DMD to swap in and rule out if it's the DMD or something else. It seems whatever is supposed to drive the Y position of the pixels is failing to do so, so the dots are all rendered in a stack at the bottom. I took a short video clip of it, I'll post shortly.

Update on my display issue - I replaced the DMD with one from a friend's Twilight Zone pin. Worked. Looking over the babcock branded display that was in there, it seems like a section of the board north of the power connectors was cooked. Should I be concerned for the currently working one?

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Thank you again for the good advice. The color display will be an upgrade I'll look for in the new year.
For now, I've gotta shop all the rubbers out, figure out how to clean out dust from the habit trails underneath, and fix the left cannon error (it's not the switches, and it's not a dirty opto, so I'm guessing something with the wiring or a cold joint).

Maybe I'm using the wrong nomenclature, but aren't the optos the infrared emitter and receiver that let the game know a ball is in the cannon?

I finally got into it last night, unscrewed the cannon shell and found the receiver side had a broken off wire (orange). Re-soldered it on and that seems to have restored function. Interestingly enough, the receiver PCB doesn't have a through hole for that wire.

Worked through a few loose bulbs that weren't working, and replaced a majority of the rubber bumpers, it's amazing how much better the game plays now.

Discovered a few of the plastics are cracked and warped, but going to leave it as is for now.

I noticed the Romulan ship light/strobe isn't working, how does one test that light (and the red flasher in the back right corner, as well?)

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The Romulan Warbird 'Flasher' under the green dome isn't working. I put it into test (and close the door) and everything else on the board is lighting up. Obviously thought the bulb was burnt, but it's not - I traded the bulb with the one behind the 'Return to Duty' flasher and it worked fine. I unscrewed the connector, was a little tarnished but cleaning it out did no change. Tested with the voltmeter (AC, 20VAC setting) but I was not able to get a solid voltage reading, was floating/bumping between 0.5vac and 2.3vac unsteady. I traced the wire (green+white and red+white) to a molex connector, tested voltage there as well, same results. I do have continuity from the molex through the wires and bulb.

I guess next step would be to trace these red+green wires to see where they are connected, but does anyone have an idea what could be going on?

Thanks!

Got to test this just now, confirmed, Right Ramp Flasher (SOL 42), aka the red flasher in the right side, works.
I have to move some stuff around to get into the backboard, but I'll try the ribbon cable flip first to see if its a data problem or a transistor issue...
Is there a particular variant of TIP102 I should be shopping for if I need to replace it?

Thanks for the hints!

Ok, I did the ribbon cable flip (on both sides), but that didn't make the Romulan flasher light. I flipped it back (red stripe on ribbon should always be on pin 1), and then it did, but the Right Ramp Flasher didn't work. Seems like the ribbon cable is marginal. I pressed down on the ribbon terminals with some pliers, and gave a very gentle squeeze to the pins on both boards to improve contact. After that, both flashers are working!

One remaining issue I have. Neither the left or right bank switches (Ferengi Jackpot and Klingon Assistance, respectively) are registering closed ever. Service menu resports top, middle, bottom haven't been triggered in a while.

I've looked underneath the switches seem to make contact, so I'm guessing it's something upstream.

That was it, broken Green Black at the switch for the drop target. Detached upstream, still worked for the other two switches in that row. I think all known issues are resolved now - at some point I'll need to clean up the subway system.

Thanks @pin_guy !

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My STTNG has had a non-working Romulan flasher for a while. I replaced the ribbon cable, but that made it work for a little and then it stopped again. This past weekend I performed the tie back mod to the 8-driver board using Zaza's method (resistor array + 10k) as mentioned on Pinkwiki (http://pinwiki.com/wiki/index.php?title=Star_Trek:_The_Next_Generation). I looked over the ribbon cable pin connectors with the magnifying glass but they all look good so I didn't touch them up.

The Romulan flasher is now working consistently. I noticed there's a toasted spot in the middle of the board, so I'm wondering if the transistor is running hot/going bad. I'm not looking at a gift horse in the mouth, but would the tie down help a flaky transistor that drives the flasher stay functional?

I'm thinking the smart idea is to probably let it be until it fails again.

STTNG-DriverBoard-Back-TieDownInstall (resized).jpg

Got a newbie question regarding the General Illumination (GI) on STTNG. I'm looking to replace the poor melted Klingon Bird of Prey with the Hallmark ornament. It seems like the GI wiring can support the new KBOP lights directly (in my brief testing). I did measure the AC voltage at the sockets and its coming in around 3.6VAC with the bulbs in, and 4.0VAX with the bulbs out. I thought it was supposed to be 6.3VAC? Is this normal or am I measuring it wrong?

Yep, that's what I did, it's ~3.6VAC instead of the 6.3 I was expecting.

Problem #1 - *new item* the left cannon loads up a ball, you press the trigger, the audio effect for the cannon sounds off, but the ball isn't ejected... for another second and a half, by which time of course you've missed your target. Consistently intermittent, sometimes it'll actually behave as expected. Any suggestions where to start? This was the cannon that had the leads that had to resoldered.

Problem #2 - My Romulan flasher is also not working (again). Bulb isn't the problem. I'm thinking transistor on the 8 driver board? The tieback modification (resistor array) seems to have helped it for a bit but now nothing.

#1 was a detached soldered purple wire at the top of the coil. Thinking as it rotated the wire would touch eventually and trigger the coil to eject the ball. Fixed.

#2 was interesting, I decided to give the wires a firmness test, and that seems to have connected whatever was loose. Romulan Flasher is back in business. Funny enough, now I have spare TIP102s and the transistors if I ever do have an issue.

Thanks for the assists as always, this thread is amazing.

I had read about Rikers Poker Night game (you can enable it in the diagnostic menus) but only learned yesterday how to activate it. Basically, when you get the holodeck mode (video mode; aka shuttle through the caverns game), you are prompted to take the 25M or try the video mode. The hidden Riker's poker night is accessed through there, you basically hold the phaser trigger and the right flipper button to get into it. You're given a poker hand, then you select a card left and right flippers, then trigger to discard. Both to finish your hand.

I only won 1 time out of 4 games I played. You get points for beating Riker and then for the type of hand you have (4 of a Kind netted ~ 45M points).

STTNG is my favorite right now, so many levels of challenge.

Anyone using NiHM rechargeable batteries in this role besides me? Any reason I shouldn't?

Hey folks... past few weeks my STTNG developed a habit of resetting during a game. I went through the backboard, pushed down on the connectors, replaced the batteries while it was on, and it seems like that helped, played a few games, no problem.

Over the past couple of days, I moved the game and the problem is back, and seemingly worse - you start a game and it resets, and it continues to reset, never coming back. I unplugged it for the moment. I'll check voltages, but what else should I look for?

The reset doesn't seem to happen at any particular action in the game, it just seems random...

This is a great pointer and I'll follow up with this. I did lift the playfield, measured voltage at the tap to be 113.6 on, 115.1 with the power off. Unplugged and replugged the connectors to the transformers. Played a bit, and then it went on its reset rampage. I'll report back when I verify as per instructions.

Voltage at TP2 (test point 2) on the Power Driver Board is 4.98vdc. (for ground I went to the plane screw cause I couldn't find the ground TP).

Voltage at the CPU board (ROM Pin 32) is measuring 4.93vdc. I did re-seat the connectors, the voltage at the CPU is now 4.95vdc. Given the difference it seems like I need to re-pin the connectors between these boards.

Where does one source 'trifurcon' connectors to re-pin the connectors?

STTNG-PowerDriverBoard-TP2-voltage (resized).jpg

I'd seen the reference to the 'Z connector' and was wondering what the heck it was, I was also looking at these connectors/wires and wondered if this hack in the middle of the grey cables was original. So much learning.

Hey folks, I did replace the 7 pin connector with a trifurcon (I've not had good luck with IDC previously) to the CPU board. I've not replaced anything else. It's gotten much better, but I'm occasionally still running into resets. I read that some folks take the Z connector out of the equation and straight wire it, as it was something they used in factory but doesn't really have an operating need. Thoughts on what I should try next?

"Leave it alone!"

Ok, so where else should I debug this intermittent reset issue.

PinGuy my apologies, I didn't mean to imply anything negative with the 'leave it alone' - it sounds like you don't recommend removing the z-connect and wiring those directly as a 'fix' for random resets - leave it factory is what I read.

I'm willing to try anything on your guidance. My next step would probably be to remove and inspect the CPU board if those pins have a cold solder or something.

Follow up, all the easy stuff didn't help - Repinning the connector, no improvement. Modification of removing the Z connector between the power and cpu boards. Came out nice and tidy, soldered and heat shrinked. That too didn't help. Resets coming more often, and the voltage is at 4.7vdc on the cpu. Machine will stay on if I disable the high voltage by opening the front door.

I ordered up the Bridge Rectifier/cap kit from Marco. Watched a few videos on folks replacing them; aside from the hint of replacing the BR that share the heat sink by mounting them on heatsink before soldering, any other suggestions on avoiding pitfalls?

Another thing I discovered - seems like there is some screws that cut through the playfield (I'm guessing humidity and expansion/shrinkage in heat?). they're behind the flippers but what would you do to fix this?

STTNG-PLayfieldScrewsThrough (resized).jpg

(Self Resolved).
My Bridge Rectifier kit came from Marco (I was surprised how fast).

Most of the original capacitors were out of spec on my ESR, the 'worst' was measuring 9202uF. Closest one was 13000uF- they're supposed to be 15000uF

The capacitors have thick hook like legs, so my desoldering gun didn't really work with it. I did lift a trace on C30 capacitor when it popped out before I had removed all the solder. I was able to solder to the remaining trace, run the wire through the whole and wrap it on the capacitor leg. Tested ok. See pics for how I resolved it.

The rest of the repair went as planned. The voltages are much better, 5.01vdc at TP2 and the CPU board is coming in at 4.97vdc at the chip leg.

Board powered on, all LEDs are lit, game booted, game on, BUT...

The playfield lights are not working - general illumination is, but 'The Final Frontier', 'Shoot Again' and the mission lights are not working.

Any hints as to where I made a mistake?

Update - figured out my loss of play field lamps was due to a lack of 18vdc. The C7 top positive trace must have lifted as well as there was no continuity from TP8 (18vdc) to the positive posts of C7 (but there was to C6). I added a jumper wire on the back between the + posts of C7 and C6 and that resolved it.

Test Point voltages in the Power Driver Board, in case someone asks:
TP1 - 13.45vdc
TP2 - 5.02vdc
TP3 - 11.89vdc
TP6 - 71.1vdc
TP7 - 21.1vdc
TP8 - 0.03vdc (is this right?) Update - no this is not right. When working is now 14-17vdc

PowerDriverBoard-C30TraceLifted (resized).jpgPowerDriverBoard-Tracerepair1 (resized).jpgPowerDriverBoard-C30TraceRepair2 (resized).jpg

Always a fun adventure with STTNG - it's now complaining about 'CHECK SWITCH F4 - L. FLIPPER BUTTON'. Flipper is working fine, however, selecting items by pressing left button does not trigger it (Command Decision, Shuttle Craft through tunnels video mode - won't turn left).

I cleaned the optos on the left side with alcohol+qtip, but no fix. I did notice one of the resistors on the board got extremely warm to the touch. Do I have a fried opto and need to replace it? Is there something else I should check first?

Thanks as always!

Thanks for the suggestion! I did swap them - I found out that both boards have to be plugged in for either side to work - they cleverly used the same board for both sides, just mounted inversely. The busted board didn't trigger the bottom flipper when plugged into the right side. Ordered a replacement opto board (16$) to quickly get it back working, and I found the opto part itself for 6$ (so I can try to repair and keep a spare board if it peters out again).

Thanks for the suggestion.

Got a question on setup, perhaps this is a newb question - I had noticed that I was getting a frustrating number of right side drains. Left-right/side to side wise, I'm spot on 0 degrees. I don't have a bubble on my game, but I hear you should generally have the playfield at an angle of 6.5 degrees.

My iPhone has the Measure app that uses the accelerometers to figure out angles. I placed it flat on the playfield right where the flippers are. I was at 3 degrees. After adjusting the front levelers all the way up and the rears as far down as possible I got it to 5 degrees. My garage slopes outwards, STTNG is facing up hill so I'm guessing that's what I'm working against.

What process do you go through to set this? Thanks!

Is this something thats actually admitted by Marco or just YMMV going forward?

Hi folks, I continue on my multi-year dialing-in of my STTNG. Previous posts mentioned I rebuilt the power board, replaced ribbon cables, cleaned out the troughs, replaced a broken left flipper opto, and set the playfield angle to 6.5 degrees among other things.

The game plays, but feel the flippers are weak - right top side I can rarely/barely make it up the Delta ramp and left orbit is lazy; left flipper has difficulty getting into mission start. I did rebuild these (coil sleeves, links, the usual from the kit), even though they seemed to be ok, and it didn't make a difference. Read through a few threads, did some preliminary info gathering and wondering what else I should try.

The coils are 11629s, I didn't replace these but they do seem to have been replaced at some point (they look new). The 50V test point is coming in at 69.2VDC. Voltage at both bottom coils are ~43vdc when triggered at rest (is that low?). I checked the EOS switches but it didn't seem off (and weird that would affect all three flippers).

What else should I check?

STTNG-FlipperCoils (resized).jpg

Yes, replaced Bridge Rectifiers and clip-caps on the Power Driver board.

I checked 12vdc at the power driver board and it was ok. Didn't check Wall voltage and will do so next time I'm near the machine.

I pulled the Fliptronic II board itself out to measure the diodes in the bridge rectifier there -
across the two ac inputs it's open.
AC input to + is 0.530
AC input to - is 0.523

Since a diode reading between .4 and .6 is ok, guessing the rectifier is fine, even though its mounted bent. (see pic).

Fusess checked out ok as well. What else could be causing weak flippers?

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Into the Fliptronics, for the wire at Fliptronics J901 is measuring 51.8VAC; this is fed from J104 at the power board, the voltage there is 52.0VAC. Not too much drop across the IDCs.

At the test wall plug inside the machine I'm getting 116VAC (this is my wall voltage).

More info - the 13.1VDC was measured at Power Board TP1, which led me to think 12VDC is fine - I think it's not because...
I looked into the 5VDC and 12VDC into the Fliptronics (J904-1 and J904-2 respectively), they're reading 4.99VDC and 11.89VDC respectively.

I didn't realize the other 12V line is off TP3, which is kinda low in alignment with what I'm seeing at the Fliptronics board - 11.89VDC. The power board was rebuilt with new bridge rectifiers and snap on caps. What else would I need to look at for this to come up some?

Want to say thanks for the guidance and help provided so far. You've been great!

I used the Marco Power Board rebuild which had these parts, nothing else changed:
KBPC3504W(5 pieces) BR1, BR2, BR3, BR4, BR5
C15KM25VR capacitors (5 pieces) C5, C6, C&, C11
C100M200VR capacitor (1 piece) C8

The STTNG is stock incandescent, before the power board rebuild I had a lot of reset problems that have since gone away.

Q2 is the LM7812 12vdc voltage regulator - might consider replacing that with the PSU3-12? Would I keep the heatsink and related capacitors?

Attached the diagram, which caps should I take a look at? Pinwiki says C6 and C7 smooth out the unregulated 12v, replaced when I rebuilt the power board. I've got a ESR tester that can give me an idea of what may be off...
Williams-A-12697-1-WPCPowerDriverAssembly (resized).jpg

Hey folks, I did some work on the boards to deal with the weak regulated 12vdc. Originally was wondering why the flippers didn't feel snappy enough, led to investigating the 12vdc, and when I put a multimeter on TP3 it would hover at 11.89 and drop lower while the game was in attract.

On the Power board I replaced Q2, the 12v voltage regulator with monkfe 's suggestion: https://www.ezsbc.com/product/psu3-12/ - little more expensive but solid.

On the Fliptronics II, I replaced C1, added C2 (mine was missing), and also replaced the bridge rectifier even though it tested ok [maybe unnecessary].

After this work, the reg 12vdc is steady with barely a drop to 12.98vdc, and the game is more responsive - I was even able to get back on the high score table.

Thank you monkfe for your help!

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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!

In test switch mode pressing the flipper buttons registers the full sequence for flipper. I didn't try touching the coils but I will the next time I've got the game on. The weakness appears on maybe a second or third shot, first one after a bit usually works well. Perhaps promising...

Just as an update - I checked and cleaned the flipper optos, and additionally replaced the remaining original one with a new one ( so now both flipper opto boards are gulf repros and there are 2 black diverters). This did not make a difference.

I refurbished just the top right flipper, as that's the one that was really hard to make it up the delta ramp. As you may know the flipper kits do not include the bushings, so those got ordered and I replaced that one and checked everything else was clean and good. No drastic improvement on performance. I went through and refurbished the bottom pair too including coil sleeve, EOS, pawl, bushing. Not much improvement there either.

I also replaced the trough board as the infra LEDs on there were looking tired and there was signs of previous repairs - this was a long shot because the original board was working appropriately. No change on flippers either.

Noticed the coils are FL11629 on right side flippers, FL-17636 on left. They all feel weak so I'm thinking the coil difference is probably not it.

Any other ideas?

My STTNG is working, but I've got weird glitches during games, for example, random sounds as if something was triggering (like the Klingon Assistance target sounds), and one time we ended up with a multi ball without having triggered such a mission. I've tried banging and shaking to see if its a switch issue but it appears not. I've also seen inconsistent power from the flippers on occasion, but at this point I'm chalking it up to me being an inconsistent player. One of the other posts on this thread made me wonder if I was having other issues, and so I booted the game up, went to test and snapped this picture. The matrix doesn't look like it should, but I haven't debugged what yet.

I've done a bit of work on this one; power board has had regulator and caps replaced. Voltages check ok now (they were low before, leading to resets). Both flipper opto boards have been replaced with repros. I replaced the 7 LED trough opto board because the original one was crispy and had some bodged repairs on it.

What could be going on? Maybe the emitter side of the trough board?

I will say, even glitchy, I really enjoy playing this game (even though I'm terrible at it!).

Thanks.

Edit - Comparing to which switches are supposed to be closed, switches 36, 37, 41, 64, 65, 66 are open when they shouldn't be.

36 - Under L. Gun Sw 1
37 - Under R. Gun Sw 1
41 - Under L. Lock Sw 1
64 - Trough L.R. 4
65 - Trough L.R. 5
66 - Trough L.R. 6

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Neat Star Blade arcade machine next to the STTNG! I've not seen one of these in person since 1994. That fresnel lens is crazy for the visuals.

The Romulan ship is definitely in a different spot, it should be on top of the green flasher. Get the Klingon Bird Of Prey Hallmark, its got great detail to replace the original. You can also do the Romulan Warbird Hallmark as it looks a bit better. There is some excellent threads on how to make these mods.

Hello experts... hoping you can help me with this one. STTNG has been working well, and after sitting idle powered on (hours) it went bananas, continuously firing the balls up, to the point of getting them stuck in the launcher. Switch test showed there was no balls registering for the trough. I figured the trough board (the emitter, easy one to swap out) finally went and replaced it with a spare I had, and we were back in business.

A day later, it went bananas again, firing balls and ejecting from cannons and VUK and Borg ship. I thought it was weird that both on my boards died so figured something was off upstream. I checked the voltages at the Test Points on the PDB, all look solid good 12v, 14+v and 5v steady - the PDB was rebuilt a few years ago and has been solid, fuses look good. I checked the voltage at the trough board, and the 12v is extremely low, ~2volts - that's Weird. I disconnected it, measured 12v at the receiver trough board, similar, very low. Disconnected that, still low. Read a bunch of links and posts trying to figure out what'd be causing this, run into a post about the opto board under the playfield as an occasional source of issues - this was the only board I've not interacted with on my game yet; thinking maybe I've got a bum LM399 I pull that board, looks ok, but I'm not sure how to test/validate it. What I did discover is that the 12v line came back to normal at the with all 3 boards disconnected. So I'm stumped as to what to check next.

To Summarize:
Game is ball seeking like crazy.
Test Points on PDB all check out.
12v under the playfield connector voltages are all low, ~2vdc-~4vdc depending if either trough board or the opto board is plugged in.
With no boards connected the voltage on the harness matches what's on PDB, 12vdc.

What should I try next? Thank you!

I've never heard this one before, when does this one get triggered? When you get a 3rd return to duty or is it just random which one of the 3 you get?