Well I guess I could see that with those newer Sterns and JJP, not as likely to need repair especially with home use.

The fix isn't actually covered, but we can in a future episode, because I actually haven't done it. Hah.

Just watched that second video of yours. Dude, mind me asking what you paid for it? It really does look freaking factory new. is it HUO!?

Oh yes, it is 100% HUO, no doubt. The guy purchased it 24 years ago, put it in his basement and it never moved. Only a little over 300 plays total, it is totally mint. He was a nice guy, if he ever reads this - THANKS AGAIN! What an awesome trade for both of us, hope you enjoy the WOZ!

I just played a couple games and the drop target seems to work fine. Hope I didn't wake the family up!

http://www.pinballrevolution.com/threads/13-sttng-tie-back-mod-best-way.3954/

Wow! I guess it is worth a WOZ. It's the mint-est looking STTNG I've ever seen. Very cool, you gotta take some more photos and videos of it so we have good reference material for what a brand new unmodded STTNG looks like.

Yea, I'll have to do that. I don't plan on modding it except for the led lights. I bought the GI board for the backbox led lights and it will come with a bracket to mount it so I don't have to screw anything into the backbox to mount it. I want to attempt to keep this thing flawless.

Thanks for the link! If you get a chance, can you provide a bunch of pics of the tie back mod you did on your STTNG? I am assuming you did it just like they described in that link. So they cut the wire down at the drop target coil and pulled it back up into the backbox then made a plug with that single wire (removing the excess wire first) and plugged it into connector J108 on the PCB board. Seems straightforward. If anyone can provide me links to the 3 items I'd need to do this job, maybe from Marco?

I already have a wire cutter/stripper, but I would also need...

-Crimping Tool
-1pc trifuricon pin
-3 Position 0.156" Molex Connector

I actually haven't done the tie back wire fix yet, it's on my todo list. With the game OFF, I did check the small wire to make sure it's not weakened and is soldered good. Gave it a tug and inspected for frays, etc. Mine is on there nice and solid, so I'm not in too much of a rush.

The tieback mod has been covered many times on Pinside, maybe we should make a specific thread about it so we can easily refer everyone to the thread??? I just did a quick search and there are no decent specific threads on the topic. I'll describe it here and maybe I'll make a specific thread on it when I have time.

If you look at the larger coil on the drop target, you will notice that in addition to the 2 larger power wires (purple with green), there is a smaller purple with green wire. The smaller wire is the tieback. Its purpose is to tie the clamping diodes located on the aux board to coil power. Clamping diodes are sometimes located on the coil itself but in this era machine, they were located on the driver boards. The way the Aux board was wired required the use of this tieback wire. It usually works fine. The problem comes when the wiring frays or a hasty replacement of the coil ends up with a weak solder joint on that coil and the small wire falls off. When this happens, there is no path for the clamping diodes to clamp the EMF created by the magnetic field breaking down in a coil when it it powered off. As the machine continues to run without the clamping circuit, the EMF will soon destroy most if not all the transistors on the Aux board.

The easy, quick fix to reduce the possibility of this happening is to remove all 3 purple with green wires, solder them together and to a short length of 18 gauge wire (a couple inches will do). Do a good job soldering the joint of the 3 wires and the jumper wire. Use heat shrink tubing to insulate the joint. Solder the single end of the jumper wire to the coil lug. This will ensure a solid joint between the 3 wires and avoid having to get all 3 solidly connected to the coil lug (which can be tricky).

.

Thanks, sounds like a good idea.

Same here. Famous last words though eh?

STTNG owners here just plainly rock. You guys rock. I mean it.

Maybe because STTNG forces owners to do things.

I'll put up some videos of my full led install. I have to admit, I was a little nervous picking up a STTNG with my limited repair experience. This probably won't be the last time I fix something on this. I really do need to do that tie back fix though, just for peace of mind.

haha, there's no probably about it. these things do require maintenance from time to time. most likely a few months from now you'll be posting about how the left VUK unexpectedly put a second ball into play during a non-multiball mode ...

Yeah, my old trough opto boards were too finicky, so I ordered and install these from great lakes modular:

**6/15/2016 ORDERED**
Orig Part: A-16927 - 7 Ball Trough LED PCB Assembly
Orig Part: A-16926 - 7 Ball Trough Photo Transistor Assy.
1 - DCS-TBS - Widebody Ball Trough Board Set - $60
If paying by Paypal, please send payments to:
[email protected]

The resistors on the original boards just "cook" and get burnt out. With this new opto tech, no more super-hot resistors. I've been good ever since!

I'm not sure this is any easier or quicker than the method I linked. The things I like pulling the wire up into the backbox is, it removes the PF and coil area from the equation, future owners will easily see the fix has been applied when doing a backbox inspection, and no soldering needed.

Yeah, now I'm paranoid and need to do the fix.

pcprogramer I was looking at your video of the repaired drop target and would like to offer a suggestion.

The current location of the switch insulator pad on your drop target switch seems incorrect as it has no function in its current location. I feel this pad should be on the opposite side of the switch where the switch attaches to a metal plate, this will allow it to offer some protection of a bent lead on the switch shorting to ground; additionally, having this insulator behind the switch will add additional clearance between the drop target and the actuator arm, allowing it to fully clear the drop target rather than dragging on it.

STTNG #9 (resized).jpg

I didn't want to spend $135 for the laser mod so I found a source for lasers cheap. Does anyone know what power source the existing mod uses? I noticed the domes on the cannons flash when in that mode, so tying into those lights won't work. A gi light will mean it is always on. What bulb or power source should I tap into?

Thanks, I'll take a look at that tonight. That metal arm does seem to close to the inside right now.

It taps into the power for the motor rotating the canons. Mine hooks onto the motor lugs directly. When the canons are moving, the lasers are on.

Alright, anyone have a suggestion on how to reduce the voltage to this diode laser. It is rated for 5v. The cannon motor is 12v. It fries the laser. Is there a resistor or something that would knock the current down to 5-6v?

0204170651 (resized).jpg

Yes, the formula for the resistor (R) is:

R= (Vs - Vf) / I

Where R will be the value of the resistor; Vs is the source voltage, 12V in this case; and Vf is the forward voltage of the LED, 5V in your case. So the value of the resistor is going to be 7 / I where I is the current through the laser, this is unknown to me.

If it was 20mA or .02A you would come up with a value of 350 ohms.

To calculate the wattage of the resistor you will to multiply the diodes forward (Vf) times the Current (I) draw the diode. In the example, I used 20mA for I, so the wattage would calculate .1; while you can use a 1/8W resistor, I would use the next higher wattage resistor which would be 1/4 Watt.

If you don't like doing the math, there are plenty of on-line calculators to perform the math for you.
http://www.ohmslawcalculator.com/led-resistor-calculator

**The resistor is hooked up in series with the LED.

edited for standard led current of 20mA ... again, you need to substitute the true current draw of your laser diode for I. If the laser is too bright, increasing the resistor value will reduce the power of the laser.

I would not recommend a resistor. Inductive feed back from the motor may have adverse effects on the laser diode.

That's a valid point Zitt, but I think I would throw caution to the wind on this one...even if you reduce the lasers life expectancy by a factor of 100 it's still going to be good for 1000 hours, and 1000 hours runtime on a STTNG cannon means it will work for generations

Here's a question for you guys.

What is the "proper" position of the "Advance in Rank"/"Command Decision" plastic lamp board under/in front of the Romulan ship? When I look at IPDB photos it seems it is placed in front of the top surface of the Delta Ramp in front of the Romulan ship but there are no mounting holes in the supporting plastic for this location. Mine came "wedged" under the Delta Ramp under the Romulan ship using the mounting holes located toward the back of the supporting plastic piece.

Any ideas or opinions?

You should get a lot of oppinions on this as this piece really never seemed to fit well. When I did my restore, I replaced this plastic as it was bent and scratched from being wedged against the delta ramp.

What I did was pulled out my Dremel and used it to trim the top part of the delta ramp so this piece can mount without hitting the ramp. This in no way decreased the strength of the delta ramp as there is still plenty of material there.

Before:
Before (resized).jpg

After:
IMG_1886 (resized).JPG

Update on my issues with the alpha ramp switch (sw 23) triggering two other switches (33,43) and the game stopping after 5/6 balls in final frontier .

Alpha ramp issue:
The alpha ramp issue doesn't appear to be impacting anything gameplay wise. I realized I had the diode backwards after some screenshots of this switch were provided by a local pin forum. I swapped the diode, but it is still trigerring the other switches. Like I said, nothing seems to be impacted gameplay wise, but any idea what could be causing this? The switches are all on the same row (23,33,43), so it seems like that might be some type of clue.

Final Frontier issue:
I was able to find the issue is with the trough optos 5 and 6 sometimes triggering when the coin door is closed. I was able to wiggle the board some to get them to not be triggered, but it seems very finnicky. Any idea how to alleviate this?

Saber, I just reviewed your original post and am sure you have a switch matrix problem in row. To be honest I didn't see a problem with the diode in your first picture, but its such a tight closeup I had a difficult time discerning the orientation. Please see my post https://pinside.com/pinball/forum/topic/100-sttng-fix-me-challenge-experienced-techs-only/page/2#post-3556239 where I attempt to clarify what you will see when you have a shorted/backwards diode in the matrix.

Thanks Pin_Guy, I think I might just have the wiring on the switch wrong after looking at the picture again. I think the white orange wire needs to be soldered to the other end of the switch. Would this cause the matrix issue?

Would you or someone else be able to provide a picture of your switch for reference? If it's not easily accessible, don't worry about it, kind of a hard switch to get to.

I think I'll try to switch the wiring tomorrow to see if that fixes it otherwise.

Laser diodes are temperamental beasts in general. While developing the Stern Star_Trek Laser upgrade... I think I burnt out 2 or three.

The Operations Manual shows the clear plastic piece (03-8630 Guide, Actuator) on the outside of the switch, and it's positioned upward to prevent the switch lever from being pushed sideways (toward the left side of the cabinet). I don't know why, but it seems to end up positioned downward, maybe because someone thinks it's supposed to shield the wires. When I bought mine it was positioned downward and my switch lever had a lot of lateral play in it just like pcprogramer's switch. The shape of the tab on the drop target tends to push the lever sideways, so I believe this plastic should be placed on the outside of the switch (as shown in the diagram).

The switch was acting flaky. Data would say, "lock is lit" at random times, like when I'd use the flippers before ball launch. I replaced the switch and reused the lever after bending it where it connects to the switch to make it tighter. It's been working well since then.

My left cannon laser stopped working and I noticed there was a transistor soldered and heat shrunk inline with the wires. This transistor would get very hot when the cannon motor was on (when the laser should be on). I'm not sure if this was a problem with the transistor or the laser shorted out. I did accidentally let the cannon rod fire into the laser when I was working on it, so the laser itself may have been damaged. I just ended up removing both lasers. The cannon modes are too easy with the lasers IMHO, but I'm curious about how/why the lasers fail.

I think you hit the nail on the head. The only thing that should be there to protect the wires from shorting is the fish paper sandwiched between the switch and mounting bracket.

delta made (resized).jpg

The lasers are 650nm 5mv 5v

5mA or 5mW?

I'm going to assume 5mW. Since power in Watts (P) is equal to Current (I) multiplied by voltage (V) or P=I*V then the current draw of your laser will be I=P/V or .005 / 5 = .001A (1mA)

Using the calculations listed above you will find that you need to use a 1/8W - 7K ohm resistor. This seems like an excessively large resistor to drive anything, so my power assumption may be incorrect.

Power output 2-5mw

Do you think they have the resistors on ebay?

I think the problem here is that the 5mW power of the laser is going to refer to optical power of the light and wont correlate to the power of needed to drive the laser, I am fairly certain that the laser will not light with a 7K ohm resistor inline with it.

I wonder what ones they use in the mod. It appears all the 12v ones are fairly big. Mine fit perfectly. Oh well.

What I would suggest, is actually measuring the current draw of the laser using a 5V power supply or a battery box with three AA batteries. If you are unsure of how to make this measurement please look here.

https://www.google.com/imgres?imgurl=http://www.cdn.sciencebuddies.org/Files/4808/6/fig7_multimeter-series-measure-current.jpg&imgrefurl=http://www.sciencebuddies.org/science-fair-projects/how-to-use-a-multimeter.shtml&h=451&w=475&tbnid=z-r3WehGGwDK9M:&vet=1&tbnh=160&tbnw=168&docid=O_Y_uNIDYQm2RM&usg=__50FdBwTOnpQ5nZQdQheqXZozPSc=&sa=X&ved=0ahUKEwjAkrHYsfnRAhUS1mMKHYhcBUIQ9QEIHjAA#h=451&imgrc=z-r3WehGGwDK9M:&tbnh=160&tbnw=168&vet=1&w=475

Correct! If you don't know the power consumption (in mW or amperage) the calculation really can't be done. If you have a 5V power source and a meter you can hook it up and measure the current. Does anyone with the laser cannon kits that are sold know how the handle the power conversion or do they use 12V lasers? I'm not usually a proponent of reducing voltage in this fashion because it's wasteful but in this case it may be okay as long as the laser diode doesn't react poorly to the surge current when initially turned on.

I'm glad to know I'm not the only one that thinks the placement of this part is an issue. I thought about cutting the Delta ramp down as you did but was a little afraid to do so. I'm not sure where I'd get a replacement if I mess it up. What type of tool did you use in your Dremel? (stone, router, sanding cylinder??)

Thanks for the reply!

The best thing would be to update the first post in this thread. That way it would be very easy to find, and for new owners would see it
right away.

used a cutting wheel, then wet sanded it by hand to smooth it out.

Star Trek Next Generation is my favorite pinball. Over the years I have restored and repaired countless STTNGs. Every time I sold it, I regretted it. The game I have now is hopefully staying a long time.

I restore, repair and sell pinballs as a hobby. Here is a link to many of my repairs over the years. Hopefully some of them can be useful.

http://purcellvillepinball.com/BallyWilliamsRepairs.html#StarTrek

Here is a photo of the switch matrix with the balls out of the game and the balls in the game. (This has the top drop target down - which it usually is.) I think of this as a backwards "4".

http://purcellvillepinball.com/SwitchMatrix.html

I also document my restorations (when I don't simply flip one). I recently have been taking 300 or more photos during a restoration.

Here is my current baby:
http://purcellvillepinball.com/STTNG2015.html

Here is one I did for a friend while I was concurrently restoring my game above:
http://purcellvillepinball.com/STTNG2015-JV.html

Here is a restoration and photos from 2013:
http://purcellvillepinball.com/STTNG2013-03.html

IMG_6547 (resized).JPG

Happy to say that I switched the white/orange wire around and now it is fixed, no more matrix problems! Only issue now is to figure out how to get the trough optos correct 100% of the time when the door is closed. I have to adjust the opto board sometimes for it to not have the 6th opto triggered, but this is just a minor annoyance.

Thanks for your help pin_guy.

I wonder if something like this would work.
Look at this on eBay ebay.com link: itm

Not really. That is a circuit to drive the bare LED chip. Your laser pen already has that type of circuit in it. You just need a 5V regulator circuit like this one ebay.com link: 5V Out 6V to 12V In AMS1117 5 0 5 0V Step Down Linear Voltage Regulator Module

You could also use a simple 7805 regulator like this (10 of them in this listing) ebay.com link: 10PCS LM7805 L7805 7805 Voltage Regulator IC 5V 1 5A USA Free Shipping

Check the leads on the big blue resistors on the trough opto board. It's a common problem that the heat and vibration cause the metal leads to break. It will still be contacting, but vibrations (like from balls draining, flippers, etc.) will momentarily break the contact to the board and trigger the opto switch.