Like many of you out there, I am restoring my BK which I got nearly two years ago. Thank you to all of you that contributed instructions, pictures and videos!

My restoration of the cabinet went OK, but not great. I have decided to go with vinyl, but I have not been able to find any vinyl kits for the BK, so I created my own, in two flavors: the original set, and a modified one. I still need to complete the coin door, but here is a preview. Hopefully going to my local printer on Wednesday.

Original - BK Right Cabinet Vector Art (resized).png

Modified - BK Right Cabinet Vector Art (resized).png

Original - BK L&R Head Vector Art (resized).png

Modified - BK L&R Head Vector Art (resized).png

Thanks! The area you are referring to is for reference. I use inkspace, and these items are on a unique layer which I make invisible when sending the file to the printer. I intend to make this artwork available to the forum members once I have completed a successful print and installation.

Completed the front artwork (original and modified), and going to the printers tomorrow.

Schwaggs You bet: happy to help. Will post the files soon.

Modified - BK Front Art (resized).png

Original - BK Front Art (resized).png

Any idea why the previous owner jumpered the left and right switch grounds?

These two wires are connected to the driver board at 2J12-1 and 2J12-2.

Thx.

Jumpered Lt & Rt Sw Grounds (resized).jpg

Hi vec-tor,

Thank you for your reply. Here are some answers:

1. Maybe to make better contact to ground?
- Although I saw someone refer them to as a "ground", they are in-fact independent of one another, and not connected to the main ground. They are more like a "return" line perhaps?

2. Maybe one wire has a male or female connector bad on the intermediate connectors in the back box?
- Good thinking. I used my multi-meter to do a continuity check of each wire through the connectors, all the way to the 2J12-1 and 2J12-2 pins on the board, and both wires are good.

Maybe the issue is that the flipper relay is broken?

Is this flipper replay generally considered to be reliable?

After more searching, I also found this thread where the topic of bypassing these pins is discussed:
https://pinside.com/pinball/forum/topic/system-7-black-knight-flipper-problem#post-4070915
Mod from previous owner (resized).png

Thanks Schwaggs for the explanation. That helps. Will return the wiring to original, and investigate/fix root cause.

Printers had to reprint the vinyls because:
1. One image did not transfer properly from the PDF (they admitted that they had to fix it); and
2. The vinyl was super-glossy even though I had asked for an egg shell Sheen

My Lessons Learned in regards to the printing & application process:

1. Make sure that you ask for a top clear layer on top of the vinyl print - it makes the vinyl thicker and protects the print from scratches

2. Ask for scrap pieces of vinyl from the print shop. It was nice to be able to practice without the stress of ruining the final print!

3. Get a roller! Even the "soft" applicator the vinyl print shop gave me tended to make scratches. I put some velcro on one side of the applicator, and even then it was not foolproof.

4. Wet vs dry. Material was 3M Controltac for which I paid more ($284 before taxes), but I was told that it the longevity is much better. This material has channels to allow the air to exit ("air egress" feature). However, no matter what I did (with the practice pieces), I would still get the occasional air bubble. The 3M instructions said to avoid the wet method because there is no means for the water to dry if any of it gets trapped, However, the print shop highly recommended the wet method anyway. Since my cabinet had a layer of clear, and it was fairly flat, I went ahead, and used the "wet" method, using a light mist of water (with 2 drops of detergent per liter). Procedure was easy: the roller allowed me to fully push out any trapped water, and after 24 hours, I can attest that the vinyl has adhered to the cabinet very well and it was fully flat with no bubbles. Generally speaking, I used the procedure from Australia shown on youtube here (except I used far less water). Trimming just shy of the corner worked well.

5. I did not need to use an assistant. Separating the film was easy, and I used a trimmed piece of underlay to grab the end, and keep the end stiffso that the corners would not fold.

6. I used the triangles at bottom of each print to align the pieces with the cabinet, and it all lined up well.

7. I did not remove the rails, and simply trimmed around them. Worked well.

8. Total time to apply the vinyl: 5 hours. This excludes removing/re-installing the legs, and playing with the practice pieces of vinyl.

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I can vouch for CPR in regards to the quality of the print on the backglass, the rounded corners, as well as their customer service on an issue on my purchase which they are fixing by sending a replacement unit. Furthermore, they tell me that it is an official/licensed/approved design that is based on a NOS glass. Finally, their shipping box is flawless in regards to protecting the glass during shipment.

Out of curiosity on the Mayfair (NOS 2nd printing) vs CPR, does anyone know if the horse is dark grey or blue?

- My original BK black glass (early unit w/ transformer in the head) - horse (and knight) are very dark, and the horse color is dark grey
- My CPR replacement - the knight is much brighter (looks good) but the horse is a dark blue except for where the bulb is under the left hoof (bright blue);
- Mayfair replacement - is ???

Also, I am curious on how "new" the Mayfair units are in regards to scratches/damage since it sounds like they are over 20 years old.

BK_Glass (resized).jpg

Thank you both for the excellent feedback. Definitely concur that the design of this backglass is spectacular.

Hi Draegermeister. Were you able to located the BK HardTop you were looking for?

Quick question. BK has three 23-750 coils (#6, #7 & #8), yet all of these coils in my BK are 23-850s.

The 23-750 coil seems to be "out-of-stock" almost everywhere.

What is best practice?

1. Ignore and continue as is? or
2. Take the coil apart and remove 100 windings?

Thanks!

Thank you. Sounds sensible.

Hi Tomass,

Probably more than what you want to spend, but you can have my old backglass for $99 plus shipping.

You can view it in ther classified section here:
https://pinside.com/pinball/market/classifieds/ad/86821

Oh wow... What a difference! Glad to hear it got there safe and sound.

Shout out to CPR(i.e. Classic Playfields - https://classicplayfields.com/) for their awesome customer service.

I had purchased a new BK backglass back in May, and eventually, I figured something was not quite right. It seemed like some of the artwork was just plain missing.

Bird (resized).png
Missing Black Highlight (resized).png

I sent a note to CPR to ask for help with the problem, and this is the very professional response that I got:

Thank you for bringing this to us. I know exactly what those glass problems are, as a couple printed wrong on a day back in the spring, and got sat aside. Somehow, both eventually later got grabbed and shipped to customers. This wasn't known until a little bit later, when we discovered the bunk prints were missing.

We were wondering where those glasses had went. One guy spoke up many months ago and we had exchanged his. Yours looks to be thankfully found, now we can deal with it.

The raster server that runs the press had stepped the gold layer ahead one in the layers... making the glass look the way it does, mainly because the gold layer ended up covering a whole bunch of the blackline layer.

Now for the odd part... I need you to destroy the bunk glass you have. Be safe, but being tempered the glass should break easily. Wrap in a sheet, snap the edge with a hammer. The glass is tempered, so it should "pop" into a million pieces... thus best being in a sheet (or hefty garbage bag). Then I need you to forward in a couple pictures to the web site address: [email protected] The reason for this is because our Bally/Williams licensing rules enforce the destruction of repro pieces that are too erroneous to allow out there in the wild.

So story short, pop the one we sent you, and a new one will be on it's way to replace it.

So yes, even though it broke my heart, I destroyed the backglass as they asked.

20190929_165855 (resized).jpg

Within a few days, I received the new and corrected backglass with all of the correct artwork. I can also confirm that the mirror finish is perfect!

Again: huge kudos to CPR. You guys rock!

Final Install with liftbar 01 (resized).jpg

It's been tried, and it is a waste of time. Even with a light, none of the light makes it through the plastic. If you are talking about the knight looking towards the left: don't waste your time.

Just played a BK tonight at a local bar which, as it turned out, had that light, and it did nothing.

additional edit:
----------------
Here is a post that shows all of the extra lights that can be added on the right side of the playfield, both lower and upper playfields. You can be the judge yourself.

https://pinside.com/pinball/forum/topic/black-knight-clubmembers-only/page/20#post-4341589

Wow: that looks spectacular!

Do you have the specifics of your installation? (parts and location of your installation) - if available.

Yes - having the same desire as well.

Congratulations! And welcome to the club.

Same here: centered and early system 6 PS.

Totally agree on variations from game to game.

Stenciling aside, I am seeing variations on the playfield as well, with various locations for screw holes resulting in the ramp sides in different locations. My BK had the left side of the left ramp moved inboard about 1/4 in compared to other machines resulting in a ball drain every single time. I moved it after inspection of pics from other machines and playing two other machines at local bars. Sigh.

Left Ramp Guide - Before and After (resized).jpg

Here's mine: 1/4" thick foam seal with sticky back. It prevents fly-throughs 99% of the time, so yours is better. Just using what I have around the house.

20200101_163958 (853x480) (resized).jpg

I very much like the original "jeweled" look of the inserts on my BK, but some inserts have faded, particularly the blue one. I have done an LED conversion using the dimmest "retro" LEDs from Comet (and a few non-ghosting for the problem bulbs). Unfortunately, they all have white domes, which appear very white through the inserts.

I have had success using 10mm gel boot caps (for car instrument panels) which you can get for different colours from ebay: ebay.com link: 10 qty RED 10mm T10 168 192 light bulb color caps covers Toyota Honda Import

In summary: Green and Blue worked great, but the Red ones hardly make a difference. I only concentrated on the inserts close to the player. The ones on the upper playfield are too far to be visible.

And obviously, this is only a problem in moderately bright rooms.
Sample Boots (resized).jpgSample Boots - Green (resized).jpgBlue LED w and wo boot (resized).jpgGreen LED w boot (resized).jpgRed LED w and wo boot (resized).jpgRed boots installed (resized).jpg

Good eye!

So, perhaps I should have mentioned that although the caps are white, the LED itself is colored. So, I am using blue on all blue arrows, dropdown target timers and the bonus lights (X2, X3, X4, X5). What the boot does is make the white cap less visible from the top when unlit, but when they are lit, they look nearly identical to without the boot. Maybe a touch darker/richer.

In regards to the purple hue of your X2 and X5: I am guessing that it is just the way they faded, but that they were originally blue. I have noticed on older Black Knights, that they do have a slight purple fade to them (including my machine), but generally, I feel like all 4 are typically blue, but we do know that there has been variations over time.

Scanned from a playfield. You could convert to line art using Inkscape.

Good luck!

Magna_Save (resized).png

Hi,

The 10's digits on my credit/match display are blank (instead of showing zeros) and then start flashing/blinking.

Any ideas which component might be the culprit?

Thanks!

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Thank you @Schwaggs: that was it. Had not thought of reseating connectors because I completed the restoration project 8 months ago, but yes: rock solid now!

Been enjoying my hardtop. Frankly: you can't go wrong: smooth, fast, long life and gorgeous vibrant graphics quality. Graphics quality wise, here are the three items that "bug" me:

- The strip in front of the targets on the lower playfield are transparent to show the wood, which is correct, but the same strips are white in the upper playfield (argh)
- The white "errors" in both outer lanes were not fixed. I was upset at first, but they matched my original PF
- The triangular lights are slightly smaller than original (to allow for variation from PF to PF), but frankly that bothers me the least.

In retrospect, and in the big scheme of things, those are minor distractions to a superior product.

_Capture1 (resized).JPG

_Capture2 (resized).JPG

Congratulations! I know how good that feels: it took me 36 years! I was unable to beat the default score at the arcade back in the 80's, and it is only after I bought a well worn BK, restored it, that a year later, I finally got past the 2.5M default as well (on 3 balls of course). My next goal is to roll it over, but I am not even close. The good news is that I have been able to refine my strategy, which makes a difference in my consistency.

Another of my goals is to light up and win the "special", which so far, is proving to be an impossible task to do in 30 seconds.

My strategies (in order of priority) - some of which are obvious (sorry):

• Keep both magna-saves activated
• Once both magna-saves are lit, then prioritize multi-balls
• In multi-ball, maximize the 3x points by leveraging the high-value two inner lanes (lit spinner and lit mystery)
• Don't be shy or slow to use the magna-saves to capture a ball, get 5 bonus points, and to return the ball to the upper playfield
• Keep at least one ball locked in the upper-field when on my last ball (leverage the outer-lane "last chance" feature)

Any other tips?

I had (almost) the same problem, in that my settings would disappear after 1-2 days after installing fresh batteries. I found that the batteries were draining very quickly, and eventually I replaced two diodes that are designed to ensure the batteries only power the settings RAM when the power is off. The diodes I replaced are: D18 (1N5817) and D17 (1N4148), although it turns out in my case that only D17 was bad. Good luck!

The "SPECIAL" light has always been mystery to me on how it works exactly. It is not mentioned in the instruction card, and the manual was not completely clear to me, but as it turns out, is accurate upon re-reading it.

Here is a bullet point summary:

• The "Special" light will never light up as part of a single player game. It is only a feature of a multi-player game.

• At the end of the multi-player game, the person with the highest score gets a timed "bonus ball"
• Timer is set to a default of 30 seconds.
• You get all three balls and magna-saves are available continuously (yay)
• You do not get triple-scoring, and the Mystery & spinner are disabled (boo)
• During those 30 seconds, hit all four drop target banks once, which lights the "Special"
• Once lit, activate the Special by sending a ball through the turnaround. The "extra ball" will be lit (which was confusing - I was hoping to get a regular extra ball, but... no)
• Continue playing until the timer reaches zero
• The Special will reward you with another "bonus ball" 30 second session

I'll say this: it's hard to activate while under the pressure of the countdown, but with practice, it does get easier. What I did to practice:

• Go into the settings (#34), and set the timer to 99 seconds (yup, it's cheating)
• Start a 2 player game
• Drain the balls as quickly to get to the end of the game
• Practice the "bonus ball" session
• Rinse and repeat until you get the hang of it
• Bring the timer down to 60 seconds, practice some more, and then back to the 30 second default
</lu>

Ultimately, a nice additional little challenge that I had not taken advantage of until now (and the extra points are a nice bonus)

Thank you for sharing. Much more elegant solution than what I had in mind!

Correct: it is not an error code. It simply means you automatically entered "diagnostics mode", straight to "game status (2500) which is the ID of the game (#Black Knight) and Test No.4

There are a lot of 3rd party manuals out there that provide troubleshooting instructions for the Williams System 6 & 7 pinballs out there, but one of my favorite ones is the official Williams manual which you can download from here: http://blackknightpinball.co.uk/wp/manuals-instructions/flipper-manual

In this manual, you might find this Diagnostic Flow Chart useful that clearly shows a battery problem to be the reason why your machine would enter diagnostic mode from power on.

I had the same problem as you. I would install new batteries, and it would work for a while, but then it would start in 2500/4 again, and the batteries were dead. The problem was that two blocking diodes that ensure that the batteries only power the RAM has failed, which was causing the batteries to try to power the entire board, and they would drain very quickly.

I replaced diodes D18 (1N5817) and D17 (1N4148), and this particular problem went away (it's been a year now).

In your case:
1. Turn your BK off
2. Check that you have good battery voltage (as close to the RAM as you can, or from the pins on the chip itself)
3. temporarily remove the batteries
4. use a multimeter to test the diodes.
5. If the diodes are good then the RAM itself is suspect.

In regard to the drop targets and the machine seemingly confused about multiball, I agree with frenchmarky: start with cleaning all of your leaf switches. DO NOT USE SANDPAPER Use a business card, and drag it in between the contacts with light pressure from your finger. You can also use alcohol.

Diagnostic Flow Chart (resized).png

Looking at your pics, your power supply connector 3J8 for the general illumination is messed up. It looks like a previous owner solved a bad connection/overheat issue by soldering the wires straight to the board, which is definitely not a good practice.

First step is to determine if you get good/correct power from the power supply board. Hopefully you have the schematics diagrams for your machine.

1. Make sure that all fuses have correct values (sometimes, previous owners make mistakes)
2. Disconnect all output connectors (3J3, 3J4, 3J5, 3J6, 3J7) and only keep 3J1, 3J2 and 3J9 connected
3. Remove Fuse F7 (since you cannot disconnect 3J8 which is hard wired)
4. Power on the machine
5. Measure your output DC voltages (be careful: the voltages for the displays are 100 volts)
6. Make sure that the +5V is not less than +5V
7. Power OFF
8. If all the DC voltages checked out, then continue with Option No. 1 below

Option No.1 - bare minimum - requires some soldering skills

1. Remove the power supply board (desolder the two wires from the 3J8 hack)
2. Reflow every connector pin to ensure good continuity
3. Replace header 3J8 with a new header
4. Buy the connector for 3J8 and rebuild it (i.e. repin the wires)
5. Re-install the power supply board (with the fuses) and connect 3J1, 3J2 and 3J9
6. Power ON
7. Recheck the output voltages and now you can also check the 6.3VAC Gen Illumination circuit
8. Power OFF
9. Plug in all the output connectors (3J3, 3J4, 3J5, 3J6, 3J7)
10. Power ON**

Option No.2 - Cadillac option - takes a lot more time, is more thorough, but a lot safer

1. Remove the power supply board (desolder the two wires from the 3J8 hack)
2. *Replace all capacitors (there are kits you can buy ready-made)
3. *Upgrade all the connectors to the four-sided pins, and replace all mating connectors by re-pinning them with the 3-sided trifurcon pins
4. *Perform the 91V mod for the display power output (91V instead of 100V will extend the life of your plasma display)
5. *Separately from the power supply, add two additional rectifier fuses that Williams should have included in the first place for the +18VDC and +28VDC circuits
6. Re-install the power supply board (with the fuses) and connect 3J1 and 3J2
7. Power ON
8. Recheck the output voltages, and now you can also check the 6.3VAC Gen Illumination circuit
9. Power OFF
10. Plug in all the connectors (3J3, 3J4, 3J5, 3J6, 3J7)
11. Power ON**

Notes:
* Vid has created a "bulletproofing" post on pinside which is a great resource for what you are asking (and a lot more) that covers these topics.
https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6

**In regard to powering the whole machine on for the first time, I would check all other aspect of your machines for evidence of problems first.

If this sounds like a bit much for you in terms of complexity and work, I would rely on your hubby's "guy" if he is capable/knowledgeable. The alternative is what I did: hours of research on pinside, reviewing the diagrams, purchasing the needed parts, getting good at soldering (lots of youtube videos out there)

Good luck, and congrats on your BK! One of the best pins out there.

IGNORE THIS >> It is the "Advance" button inside the coin door.

Correction: it is the side button on the MPU board, close to the LEDs. There are two switches. It will be the lower one

Diag button location (resized).png

Diagnostic Switch (resized).png

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Looks like Marcos Specialities may have what you need. They have a spinner, the top bracket, and then you can buy the sticker. I can't check the dimensions for you as I am gone on a business trip, but maybe someone else might?

Here is the spinner I found
https://www.marcospecialties.com/pinball-parts/04-10062

Good luck.

Totally agree: I can recommend the hard top. Possibly more work to remove, sand/flatten and re-bond all the jeweled inserts (which frankly look better for that game than starburst), and despite a few minor alignment issues, the end result is spectacular. Not everyone likes the hardtop, but it worked for me and I am still happy with it two years later: zero wear and zero issues.

Ah yes - the old "fly-through" problem. Very common. There are a couple of ways to fix this, but I found that the simplest is the recommended foam block taped to the top of the 3 ball area, or to the side. Mine is on the side, and 1% of the balls still fly through, so I think the top mounted one is probably better. I actually like my 1% fly-through solution as a reminder that this is a feature of the game. For the "top" installation, the foam block is mounted either to the plastic or the to metal plate. The advantage of the side mounted one is you test and adjust the location before putting the plastic back, and I prefer to have taped to metal instead of plastic.

Going by memory - I just used 1/4" thick foam with tape pre-applied to one side. Lowes or Home Depot should have that in stock.

Here is a pic of my installation.

20200101_163958 (853x480) (resized).jpg

Thanks Mike - great response and I appreciate the explanation. And yes, you are right, there are bad suppliers and bad customers. I can personally vouch for CPR and your awesome customer service as you fixed the printing error in my BK backglass by shipping a brand new fixed one. Your communication was prompt, excellent, and your customer service top notch!

Count me in for a BK2000 playfield if you ever decide to make one!

And I miss Halifax - it's been too long since my last visit there.

Same here: my piece is broken too (stupid classic mistake on my part of raising the field without removing the balls).

I do not know of this piece being sold by itself unfortunately. Maybe it is time to ask one of manufacturers that sell the entire kit: is there anybody else need this piece only?

Although I am not a big fan of making mods to an original game, I did choose to incorporate a couple of mods which to me enhanced the game tastefully, and since I had committed to a hard top anyway, I had already strayed from what a purist would accept. With that, you might want to consider the following:

1. Adding a light on the top field in between the two ramps so that the plastic is evenly lit;
2. Painting the rails semi-gloss black - to me, that had the nicest impact
3. Adding a strip of bright LEDs under the knight on the upper field on the RHS - results there are mixed because the plastic is not very translucent so a regular bulb won't be sufficient, and the right side of the knight is partly covered by a rail, so that part remains dark. Still, I like it better that way.
4. Adding a light on the upper playfield, to the right of the right-most ramp, behind the 90 deg plastic. There is a hole there, so I was able to place a socket easily, but I had to be careful with clearance so that the ball can still travel through the trough.

I am gone on a business trip this week, so I can't post pictures today, but I could next week if you want or care, and others have done these mods too, so there are other pics available on google.

Good luck! Your resto is coming together nicely.

Nice work! You've given me some ideas as you used LED strips where I used the existing sockets which means I still have occasional socket reliability issues. And yes, the strips are very bright which I fixed by cutting off the LED strip rather than a pot - using a pot is a more elegant & tweakable solution.

Are you sure you chose the right one to let go?

This is a fix to the two green 2X/3X hyperactive (AKA "strobing") flashing bonus lights when doing an LED upgrade to the Black Knight pinball. The BK original code assumes a filament light bulb and when the light is "ON", the code will strobe the light bulbs at high voltage/frequency and will rely on the latency of the filament for the bulb to continue to appear turned on. The LED responds instantaneous to the ON/OFF pulses, thus creating the strobing effect.

I reached out to Jess Askey (http://gamearchive.askey.org/General/Collectors/Jess_Askey/) to find out if we could make a code change to the ROM, and that is not easily done. He also provided a great technical explanation:

So, the purpose of strobing the lamps is that with the old style filament lamps, they have residual output even after they turn off because the filament is cooling down from white hot to yellow hot and then dim. In those olden days of the 1980’s and even all the way up to recent years, the CPU and Input/Output of those hardware systems was limited. Given that you have 64 lamps in a game, that would mean that you would need 64 outputs to put a lamp on or off….. using a Matrix along with the properties of incandescent lamps to hold brightness due to the filament cooling, they were able to use the matrix to strobe the lamp and only have 8-outputs crossed with another 8-outputs… so only a total of 16 outputs… that is a factor of 4 less outputs required and in those olden days, it worked lovely. What you have of course is that only 8-lamps may be on at a time using a strobing matrix…. So it does 8 lamps at a time through the matrix and turns them on for that time period… then it moves onto the other 7 groups of 8 lamps…. Again, only 8 lamps may be on at a time and by design, you can only have a lamp on 1/7th of the time. You would think that they would be pretty dim then, however, what they did was up the voltage on those lamps so that when they were on, they turned on extra bright so the residual light was even higher and the strobing effect basically dissapeared.

With LED’s that does not work as you already know. The trick is, how can you keep an LED on while the others groups of 8 lamps are being attended too… well, unfortunately you cant. However, the there is a trick here… how can you give an LED ‘residual’ and ‘lasting’ illumination after it has lost its voltage supply? You need a capacitor, that would allow the voltage to slowly fade away and keep the LED on while the CPU is attending to the other lights. The challenge there is that you would also need a diode in line with the Lamp so that stored voltage from the capacitor did not affect the rest of the matrix, that introduces a new issue of a 0.6V drop across the diode… however, LED’s don’t need the full 6.3V so that is less of an issue.

Armed with that information, I tested various capacitors to find the right value that would turn the LED on steady during the strobing sequence, and would turn off the LED fairly quickly during the OFF portion of the sequence. I did not add an additional diode, and despite that, there was no effect on any of the other lights. I did my capacitor testing on the x3 bulb, and had an old filament bulb on the 2X location so I could compare the two side-by-side to get a faithful reproduction of the original characteristics.

In summary, the strobe inputs are spikes of 0 to 18V, but thanks to the capacitors, the 2x/3x bonus LEDs are now oscillating between 4 to 6v instead which allowed them to stay steadily on instead of strobing.

Before and after oscilloscope screenshots

Note that the capacitor value will likely change depending on which LEDs you use, and what is their minimum voltage where they remain on. I used alligator clips with various capacitors as a temporary solution until I found something that worked well (in my case, 470 uF). The LEDs that I use are the "retro" LEDs from Comet.

And here is how the capacitors are wired, but the fine print applies: i.e. "use this information at your risk".

modified wiring diagram

installation of caps

For solenoids, I use the information located here: https://www.pinballmedic.net/coilchart.html#top

Below is a link to my Excel spreadsheet of mostly the electronic/electrical parts for the Black Knight that you might find useful. It includes part numbers for Great Plain, Mouser and DigiKey and some purchase links, as well as some of my notes. I try to list the original part numbers, and alternate parts when available. Unfortunately, it does not include leaf switches.
https://www.rgbmod.org/Download/Black%20Knight%20Parts%20List.xlsx

Some day, I will convert that spreadsheet to a parts database.

Your pics of the inserts look very similar to my HT. I would describe it as a haze, fairly even over entire insert. If yours are localized smudges, then that would be no bueno.

In my case, once rebuilt and in the playroom, and without the extra lighting of the shop, they looked fine, and the colored LEDs more than made up for the fading of the jeweled inserts.

I used the retro LEDs so that they are not too bright, and I noticed that new LEDs also have colored tops on the LEDs which will help further.

Good luck, and keep your posts coming. It brings back memories.

I agree. Start with the ribbon cable and associated connectors. Does it show 11 on all displays, or just player 1?

Yay!

I recreated the cabinet side art, both the original design, and a more modern version. You can take a look at them at the following posts:

Post #1: https://pinside.com/pinball/forum/topic/black-knight-clubmembers-only/page/41#post-5188519
Post #2: https://pinside.com/pinball/forum/topic/black-knight-clubmembers-only/page/41#post-5207492

If you are interested in the art files, just PM me.