As usual Zaza is giving sound advice. Since you are blowing the 18V fuse, you are not only missing the 18V for the lamps (LED6), you are also missing your regulated 12V DC (LED 1) to the MPU since it is developed from the 18V DC; because of this it's pointless to do any work on the lamp or switch matrix. Additionally, the missing 12VR is needed by the MPU for your dedicated ground switches on the coin door, and would be why they are not working.

Edit: Circuit added so you can see where this information comes from.

18V (resized).png

Ok, I'll say it "I'll take a stab at it" ... I'm confident that you will get it fully operational. If you have to have order a a new BR1, take advantage of this time to evaluate the condition of your cannons and your three diverters; 2 are in the subway and one for the Delta ramp. All 5 of these parts were greased when the game was first assembled and this grease is likely hardened, you will want to remove all of the old grease from these parts and apply a thin coat of grease to them, I use Super Lube on mine. https://www.amazon.com/Super-Lube-21030-Synthetic-Grease/dp/B000XBH9HI

This is NOT an issue.

The checks Zaza had you do is to look for shorted bridge rectifier diodes, it seems you are reading 0.00V to ground on two readings, this is what you would also read if you put your meter leads together. I personally prefer to take resistance measurements but either way you check them gets you to the same place, you have confirmed that BR1 has two shorted bridge diodes and needs to be replace.

IMG_1889 (resized).JPG
IMG_1891 (resized).JPG

Depending on your soldering skills and equipment you can opt to replace it yourself, or have someone else replace it for you. Fair warning...things can go South really fast if the board is damaged when replacing this component, let me know how you handle the board repair. This bridge rectifier is going to be difficult to do since you basically have to remove both BR1 and BR2 at the same time by desoldering all 8 leads in order to remove the heatsink, and you would replace both of them at the same time.

I believe that is the case, without having a working 12V to the processor, it is likely reading a low on all switches and has no idea where any any of the balls are.

I the more I thought about your OEM power board, the more I felt I needed to add more information on this...it's very unlikely that BR1 and BR2 can be successfully replaced without a desoldering station, attempting to replace these with a hand operated extractor will likely result in board damage. You have several options available to you, there is likely going to be repair facilities in your area where you can get this board repaired, there are also several reputable people on this site that do fantastic work.

Let me see what happens when I pull that fuse from my machine...

Awesome! You should do fine then.

I don't believe any of these coils (other than flippers) have diodes on them so it should not matter.

Ok so on your game spazing out ... This is hard to define, without knowing exactly what the machine is doing, like I mentioned before, it will be looking for balls since you essentially have no switch matrix; it will go through a ball locate program and fire coils turn on the cannons ... etc.

Very true, the software should be smart enough to realize that all the rows are bad and give you the "check F114 and F115 message"

As a rule of thumb, the first priority in any troubleshooting is to get your power supply voltages taken care of first, and then look into any other alarms. Since you know your BR1 is bad, let's get it squared away before delving in too deep on any other issues.

I hate seeing stuff like that, It's hard to tell with all the flux residue but it doesn't look like they pulled off any of the pads. They should have did BR1 at the same time, if they did you probably wouldn't be where you are now

I don't recommend that as you could end up inducing new problems into the mix. If you really want to do that I would suggest waiting until the machine is fully working, that way should there be a new problem introduced, you can limit it to what was just touched instead of not knowing if it existed before you messed with it.

Good call, the concern here is you have no idea how hot the heat sink got before BR1 failed and this heat could have degraded BR2 since they share the same heatsink.

While you are away replacing your BR's I did a little testing for you (this is one of my favorite things to do) I simulated a blown F114 as well as row 1 ground short. While F114 was removed, I was not able to see the ground short on row 1, as soon as the processor 12VR was restored by replacing F114 the ground short showed up.
IMG_1892 (resized).JPG
This ground short will prevent any further diagnostics but also makes me curious as to why you are not seeing the blown F114 F115 fuse message; after restoring your 12VR, please post a good picture of the bottom half of your MPU board, so I can see the board and connectors, then I'd like you to remove the row and column connectors to the playfield and turn the machine on, with no information coming back to the processor, it should tell you to check fuse F114 and F115 since it will not be receiving any information back from the switches, you may want to keep the coin door open so you dont have to listen to the continuous firing of coils.

ohhhh....I just watched the video. I now know what you man by freaking out, the missing 12VR will not cause the problems from your video.

The thing I'm not seeing here is as far as I can tell there is no message to check F114 and F115 even with a blown F114 ... maybe I'm just assuming that this message didn't show up and reading too much into whats not there...

If you are concerned with it, then go for it, since you have done this to your friends without any problems I have to assume you are technically competent to do so.

After you get this put back in, can you post pictures of the connections for your MPU, aux driver, and fliptronics boards?

Any chance you can toss your MPU in his machine to verify its operating properly?

I'm curious and have to ask, have you already tried swapping your STTNG MPU with your IJ? The reason I'm asking is that the MPU in your picture is from an IJ, not that this is going to matter.

not necessary ... purely curiosity on my part. Both of the MPU's (STTNG & IJ) are electronically the same, the only difference is U6, the game specific EPROM, and the Williams Part number decal.

Again, this is hard to answer and is dependent on the skill and equipment of the tech. Would I replace a 20 year old buldging electrolytic? Sure I would, but I have the right equipment to pull the caps and while the part was out, if I had even the slightest concern about the board, I would install a solid copper eyelet in the thru-holes making this connection virtually unbreakable down the road

I do agree with this and cautioned the OP that I would be hesitant to replace these until I knew I had a working machine as you could insert additional problems into the mix.

I try not to be directive in my assistance and prefer to simply provide advice and guidance towards the repair and leave the final decisions to the OPs, after all it's their machine and ultimately their decision to make.

Yes.

1021 (resized).JPG

Yes, but, and it's a big butt. The switch on the right is not the correct switch, the switch should have three connections and a diode; if you simply connect the yellow wire to that switch itself will work fine, BUT you will induce a switch matrix problem in the game.

The switch matrix can be difficult to explain, this article does a good job of explaining it:
http://pinballrehab.com/1-articles/solid-state-repair/repair-guides/146-switch-matrix-theory-and-troubleshooting

Essentially what will end up happening is that when the any other column with a closed switch in row 1 (White-Brown) is pulsed by the MPU (driven low) AND your time switch is closed, you will also drive column 8 low, this low going signal will then pull all other rows with a closed switch in Column 8 low and be read as a closure of the corresponding switch in the active row.

Ok, I don't even understand what I just wrote.

I'm going to give a slightly different example using your matrix, and change the switch without the diode from the Time Switch to the RIFT Switch; what will happen is that whenever column 2 is pulsed (solid green line in diagram), row 2 will be pulled low since the coin door is closed (green dashed line); now lets say your ball hits both the time and rift targets at the same time (this happens a lot) the missing diode will allow the low row signal at switch 82 to drive column 8 low and pull row 1 low due to the closed Time Switch 81. Since row 1 is now low during column 2 time, the MPU reads this as closure of the Slam Tilt switch 21 and your game resets.

STTNG Switch Matrix error (resized).jpg

I like seeing things are progressing well, I was actually wondering if your ground shorts were attributed to broken wires or bent switch contacts, looks like a couple of them probably were.

While you have the upper playfield taken apart, I like to suggest you give a little TLC to your Left Outer Loop optos (switch 44), It's likely these have never been cleaned due to their inaccessibility. I like to recommend just replacing this set since they are very important to the game (WARP ADVANCE) and the last thing you want is to have to rip half the game apart to replace them later.

375 (resized).JPG

Since I know there are several folks following this thread, and with how confusing the switch matrix can be I'm going to add some images to show what would happens with no diode in your TIME switch.

For the test setup I went ahead and jumpered out the TIME switch diode with a pair of mini grabbers. IMO, everyone should have these https://www.amazon.com/Elenco-Electronics-TL-21-Minigrabber-Test/dp/B0002JJU50/ref=sr_1_1

IMG_1895 (resized).JPG

Next I broke out my oscilloscope and set it up to monitor:
CH1 - Column 1
CH2 - Column 8
CH3 - Row 1
Ch4 - Row 2

This monitoring was done on my STTNG with all balls removed, in this state ALL optical switches will read as closed.

IMG_1898a (resized).jpg

Now lets take a peek at what the matrix looks like...In the image below you can see the timing pulse of both columns 1 (yellow) and 8 (teal) this is what a your normal column pulses should look like; these are normally a high going signals (10-12V) and get pulled low when the column is active, during this short period of time (<.000050 seconds) the CPU is reading all 8 rows and looking for low going signals, any low seen on the rows will signify a switch closure of the switch in the active column. As you can see in the image below, both rows 1 and 2 are high during both column 1 and column 8 times since there are no switches closed in either column. The numbers you see in the circles represent the switch numbers the CPU will read as active.

Normal (resized).png

Now, let's see what happens when I hit the TIME switch on the playfield!

Bad Diode (resized).png

WHOA! You can see the closure of TIME switch #81 on row 1, but look what just happened to our column 2 trigger pulses, we essentially enabled all the switches in columns 3, 4, and 6 to pull their corresponding row low at the wrong time! The reason for this is because every closed switch in row 1 will now drive its corresponding column low due to the failure of the diode in column 8, but only when the switch with the failed blocking diode is closed, this is what can make diagnosis of this problem so hard to troubleshoot.

Yep, that's the one right there

Its not to bad, the worst part is you have to pull the three Vuk's as they sit on top of it, they all have thier own molex connector, so they should come right off, getting at the screws can be the toughest part. The entire subway assembly will then come out as one assembly, it also has its own molex connectors so no soldering involved. My subway had a fiberglass repair done to it when I purchased the game, and it seemed solid enough.

oh, yeah those are the right switches, all you have to do is solder the yellow wire onto the Green-Grey pair, this will bring over the column signal to the other switch. WPC used solid yellow wires as jumpers all over, you will see lots of them on the GI circuits.

I think that's just the lighting or the flash making the stripes look violet in color, wire colors can be difficult to read in pictures.

You may want to look into Hallmark replacements, they look much better and are relatively inexpensive.

ebay.com link: HALLMARK 1994 KLINGON BIRD OF PREY STAR TREK THE NEXT GENERATION TNG ORNAMENT

ebay.com link: 1994 Hallmark Star Trek KLINGON BIRD OF PREY Ornament Next Generation NIB

Thanks Dj, much appreciated. I plan to continue the assistance until your game 100%

A little strange yes, what is happening here is that Williams didn't rewrite the diagnostic code for the switch matrix to include a ninth column of switches in the matrix, the switch column to the right of the 8th column are actually your flipper grounded switches (switch optos, E.O.S) just like they would be for any other game of this generation. This is all fine as they added the game specific menus to test these switches.

This would also be my assumption; however, the switches on the wires here are a little odd. In your second picture (home Switch) you show the row is white-black, this actually corresponds to none of the row wires, but is correct.

What was done here is the cannons were built as assemblies with meaning they they have a molex connector to disconnect them from the switch and solenoid harnesses, even though there is a left and right cannon assembly, the actual wiring harness for both assemblies is exactly the same, this makes them interchangeable.

Speculation: I imagine its also cheaper to purchase 30,000 of harness X then it would 15,000 harness X and 15,000 harness Y.

Where you will be able to tell if its wired properly is at the connector for the switch harness, you have one pin for the column and 1 for each of the 2 rows.

Cannon Connector 2 (resized).jpg

Kind of a trick question ... keep in mind that both the left and right cannons work exactly the same.

When the cannon is aligned with wire ramp both switches should read closed, the home because this is its home point, and the mark because the cannon is in a non-firing position.

The Home switch has a very narrow close range which should be very close to top-of-stroke for the actuator arm, but not so close as the momentum will carry it past home when the motor drive is turned off. Should you align this dead perfect to top of stroke, the cannon will park perfectly, but during play it will always cycle out and back before the cannon will load.

The Mark switch has a broad range and should be open whenever the cannon has rotated into a safe firing position, alignment of this switch (or a small bend in the bracket that holds it) can cause issues by enabling the cannon to late to make your shot. So if you pull your trigger in the perfect spot and it doesn't fire, this is a possible issue.

That sure sounds backwards to me...they may have replaced the wire harness connector and reversed the pins. If this is the case, and if you have a pin extractor, it's a very easy fix. According to the matrix, the center connector wires for the switch harness side should be white-red (Left) and White-Blue (Right), while the end wires will be White-Violet (Left) and White-Green (Right).

Left Connector:

Left Cannon (resized).jpg

Yikes, these are high voltage connectors >170VDC anode to cathode and are NOT interlocked by the coin door ... you really should never touch them with the power on.

That being said $#!+ happens ... let's just call it a learning experience. This is usually not a hard repair, but depends on what actually blew; the first thing that comes to mind is blown rectifier which is an easy fix. Fortunately there is an outstanding article on PinWIKI for troubleshooting this problem if you want to tackle it yourself. http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Display_problems. You can probably just hop to the power issues section if you want to make some quick checks. http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Testing_DMD_Controller_Power so we can see whats missing.

Optional: So the high voltage section of your Display Board is shot? Just pull out both the fuses and toss them in the box with your old plasma display and install the ColorDMD! This is the single best upgrade you can make to your STTNG, and since its powered by 12VDC you wont need that power sucking, heat generating section of the display board any longer. Please see http://shop.colordmd.com/colordmd-replacement-display-for-star-trek-the-next-generation-pinball-machine/ for more information

Please take a look at the Can you see any physical damage to the board around the lower right side? you are going to test these similar to the way you checked the power board BR.

All checks with power off. You can limit your checks if you know what voltage you are missing; BR1 for +62V or BR2 for -125V

BR1
J605-1 to ground, J605-1 to C4 +
J605-2 to ground, J605-2 to C4 +

BR2
J605-3 to ground, J605-3 to C7 -
J605-5 to ground, J605-5 to C7 -

DMD Power (resized).jpg

does it, or anything else looked burned? If not, I would measure the voltage on both sides of the resistor as a starting point.

$5 for the repair kit, it pains me to say it but at that cost it's not a bad way to go for the price. I've actually done this before, since the machine was down anyway, I figured what the hell, I'll just replace it all and troubleshoot it later if it doesn't work...it worked. I would stick to the 62V side only though since the other voltages look good.

It's coming along nice! I see you got your delta ramp protector, bumper caps, and new bands installed; your playfield appears to be in really nice shape, this could be a side benefit of buying a non-operational machine I'm sure you you cant wait to play it, and I'm looking forward to hear how that goes.

There is another possibility I touched on near the start of this topic that can also cause this issue, although the problem I'm about to describe normally shows up as a continuous cycling of balls at the end of a game.

If the subway diverters still have the original factory grease on them, this grease will now be hardened and applying additional friction to the diverter shaft, rather than reducing it. If this happens, the spring release may not have the required energy needed to fully operate the diverter and leave it in a position that will actually catch a ball between the diverter arm and subway side wall causing you to have a lost ball. Later during your play, another ball comes down the subway striking the first and forcing the diverter open enough to allow both balls to pass to the VUK, the VUK would then send not one, but both balls back into play as the game knows how many balls should be in the lock.

This is easy enough to check for, just manually turn the subway diverters and then leg go, if they don't snap right back to their full de-energized positions, then you will need to address this.

Interestingly enough, when I power on my game both cannons cycle; however on a game reset, like leaving the maintenance menus, only the left cannon cycles; but, on a slam tilt reset, only the right cannon cycles.

Try not to beat yourself up to bad over it, the game is looking great!

There could be a loose connection causing issues with the optos; intermittent problems can be tough to lock down, but one thing you can try for the mission start/ball search problem is to open the door when the ball search happens, read all the Switches from switch test to try and figure out which one is having the issue.

Nope, yours are correct, I had one of the switch numbers listed wrong and went back and corrected it

All I did to mine was took it apart and cleaned it real good and it was much happier after that. It seems like there was some kind of greasy gunk in mine, all I did was clean it real good and put it back. I have no pictures of it apart

I also get a lot of air balls off mine as well, but as I recall this title was known for that, especially on the Beta Ramp targets, couple that with having a clean and waxed play field, and it's even harder to avoid, I just decided to accept it.

That's a fairly close estimate, I would charge $50 just to look at it plus parts/labor to fix it, my guess is you would be in for more than the cost of the Rottendog board no matter who fixes it. Just the nature of the beast these days.

Glad to hear you are nearly 100%. It will be nice to have a spare when you get you get your original board back.