If I power cycle it and start a new game, I can double flip before plunging the ball and it will lock up and kill the displays.

don't mean to hijack your thread @vid1900.

the solenoid power circuit is 25.5VAC from the transformer going to BR2 mounted on the ground plane and it being converted to the 28VDC for the solenoids, not much to it.
i believe in that text marked with blue they are referring to the logic circuit, which is covered in this thread post #80

Thanks, I will follow that and get the parts suggested.

Another vid1900 appreciation post.

Picked up a Gorgar that would turn on, but nothing would work. Rebuilt according to this guide, and BAM, now all I gotta do is adjust some switches.

Thank you!

So I rebuilt the power supply board caps and played a few games fine. Today I turned it on, added some credits and walked away for a while. Came back to this. It froze with zero gameplay. Is that a clue to anything?

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Is there a section of the forum that shows how to test 5 volts at the mpu, system 6?

Nice to have you back Vid

Here are the voltage based test points on the CPU board. Meter on DC. Black lead on ground. Red on the 5V or 12V test point.

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Thanks Schwaggs, that helps. I was scared to ask.

I do not know if this has already been discussed, but I would like to do it.
Sometimes transistors (Tips122, 2n2222a) circuits and other components, as already discussed, wear out over time, note that if you put a new Tip122 and a new 2n2222a, it will make the coils or things that are activated with them, take more force.
Besides in my opinion it looks more beautiful like this with new components (I have only changed the ones that my machine uses, I see it unnecessary to change the ones that it does not use)

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What, what, sorry I couldn't resist it. Some times one will introduce more problems than if they had left working components alone. Ymmv but mass replacement can end in disaster.

Wish this would be updated to include the master display board on system 7. What is weird is I have segments out on some of the numbers, not all of them. In other words, 5 is missing the middle segment but 6 isn't. Would be great if a tutorial on hunting down these issues would be on here. Pinwiki doesn't really discuss this to any extent.

This would be a killer addition to this thread. Looking forward to it if someone can oblige.

That is extremely odd, and is certainly a function of the display board itself. Definitely something to do with the BCD conversion. Can you post a video with the issue running the built-in displays test?

Also, if you have a chip programmer and a spare 2532 chip (or a Pincoder Adapter: https://pincoder.ca) can you run the Pincoder 05-displays test and post a video of that as well? That test splits things up a little more, digit wise, and may show other interesting results.. Thanks!

I can drop pictures here but can not drop video.

Took apart a system 7 the other day, examined a lot of the connectors and found two with damaged wires. The 3 wire connector seems easy enough (repin the connector although idk what pins to use) but the IDC is a little out of my comfort zone. These wires loop back around to the harness (GI maybe?), and one side of one of the wires is damaged. How can I fix this? Should I take out the wire and splice in a new one?

I'm new to pinball, should I be replacing every single connector in the back box? Or can I leave them alone?

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The old 'switch matrix zero ohm resistor' thing...

If I read things right, Williams first changed the column resistors from 1K to 330 ohm during Sys 4; rows were 1K. Then when Sys 7 started (Black Knight) they changed both the columns AND rows to zero ohm resistors, W1-W16. Then they quickly (apparently) decided to put the 1K row resistors back in where W1-8 were and W9-W16 remained zero ohms, R204-R211.

Seems like most BKs have a back box label mentioning how R196-R211 must be zero ohm. My BKs label does but my game's original board only has zero ohm columns. But I did find a pic of one BK label that specified only R204-R211. Every Sys 7 game instruction manual and press flyer I dug up that mentions the driver board changes only note the columns being zero ohm. Talk about confusing.

Vid recommends zero ohm on both columns and rows, and some original boards are that way. But if the above is indeed what Wms did, what is the reason for doing zero ohms on the rows if Wms made this change but then undid it? Maybe some issue was occurring because of zero ohms on both columns and rows vs. just the columns (?)

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Hope Im not hijacking this thread, and I do realize it's YEARS old, but I'll try anyways.....

First, many thanks to vid1900 for starting this thread, extremely helpful and a good read.....

I am a new owner of a Black Knight. It's the version with the transformer in the cabinet, not the backbox, but of course it was plagued by the power supply issues with the burned connectors and janky wiring. I have read through a great deal of this thread and have done the modification of the AC input for the bridge rectifiers...I have also replaced the bridge rectifiers with new ones just to be safe.....

I have also repinned the GI connector with new, and put new pin headers on the power supply.... Also installed new AC input connector on the board and repinned a new AC input cable connector.

My next question relates to the GI output and fusing the separate lines....I have included a picture of what the machine looked like when I got it and now how it looks after the new fuse blocks....

Statement 1: I have changed all incandescent lamps to 2SMD LED's from Comet Pinball

Question 1: am I doing this right?

Question 2: I understand that the GI fuse was a 20A fast acting fuse, should the separate lines to the individual lighting circuits be fast acting or slow blow?

Question 3: I currently have 5A slow blow fuses for the individual LED lighting circuits. I understand from reading the post that I should do a better job of sizing the fuses correctly. ( I will be taking current readings from each separate lighting circuit and sizing accordingly....) this is especially relevant to my situation as I have added spotlights on my playfield, upper and lower, as well as some comet matrix lighting strips for additional GI.

Statement: 2 I reveiwed this document for some help with fuse sizing and will be sizing my fuses to be 135% of my FLA (full load amps) on EACH circuit.....
https://uk.trgcomponents.com/uploads/media/FuseSelectionGuide_RevA_01.pdf

Question 4: again, am I doing this right? Please respond with any suggestions and/or feedback, it is all welcome, and appreciated.

Thanks!!
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Slow blow fuses are only needed if you have coils or motors in the circuit. Fast acting is what you need for lighting only. And I would not oversize a slow blow fuse ever. Not sure where you got the 135% FLA thing?? Maybe for fast acting fuses only?? As long as you don't exceed the fuse ratings in the manual, you will be fine. Separating the circuits will require measuring the current. You sound like you're doing things correctly.

The link in my first post showed where I got that information on the 135% of full load amps, I'll quote that document below....Im just going off of my research, so of course my research information could be incorrect as well.....

Also, thanks for the info on the fast acting vs. slow blow, I'll change all of the lighting circuit fuses to fast acting and re-label accordingly once I have had a chance to size them per my current measurements.

"What is the normal operating current of the circuit?
In order to select the right amperage of the fuse, you first need to know the full-load
steady-state current of the circuit at an ambient temperature of 25º C (68º F). Once the
current value is determined, then a fuse rating should be selected as to be 135% of this
value (taken to the next standard value).
For example, if the normal steady-state current is calculated to be 10 amps, then a 15A
fuse rating should be selected [10 amps x 135% = 13.5 amps, the next larger standard
size is 15A].
It is important to note that if the fuse is intended to be used in an environment with
possibly very high or low ambient temperatures, then the nominal fuse current would
need to be sized significantly higher or lower (see ambient temperature below). "

A small amount of apples to oranges but still a fair comparison, IMO:

When Williams ditched the single 20A fuse on the power supply for the GI circuit, and branched it into 4 separate fuses, they went with 5A SB. Not FB.

I've had a bit of trouble pawing through online PDF's for proof, but my Pinbot for example, has a factory-installed label on the board mounting plate next to the GI fuse holder very clearly stating 5A SB for each position. From this, I have modeled my 4 fuse modifications on earlier games to use 5A SB's.

Richard

I suppose it was to prevent nuisance failures (commercial use). For home use, fast acting would be fine. Less chance you're going to blow something up line. I learned that slow blow fuses do NOT always spare the IC chips up line on a solenoid circuit with MOSFET drivers (newer boards).

Exactly what I have found from my research....

Although, Im sure Williams did not expect or plan that we all would be changing our incandescent lamps for LED's 40 years down the road, but here we are......

Im guessing that could/would warrant a change or adjustment to the fuse values and type for safety reasons.....

Im probably diving in too deep with this and overthinking it, but I guess it comes down to the question of which is more suited for LED's

Fast acting (AGC), or Slow Blow (MDL)

Im sure there will be multiple opinions......

Regardless.....I did some current measuring on each of the 4 separate GI circuits last night and here are my findings. Keep in mind, this is for my machine, which has a few modifications/additions to the GI lighting, so your's may be more or less depending on what you have done...

I checked each circuit while playing a normal game and observed the meter amperage reading going slightly up/down at times..readings are averaged....

Insert Board Circuit #1 (Backbox) - 700mA

Insert Board Circuit #2 (Backbox) - 730mA

Playfield - 1.6A

Cabinet (Coin Door) - 180mA

Interesting point. But, not all of us are swapping to LED's. My games are all still loaded with incandescent bulbs, original type displays, original type boards, etc. Not really interested in changing them. But that's me!

Richard

Great point, yes, sorry, I should not have made that statement/assumption.....

some will still be using incandescent.....

Thanks.

I’m in that group for most of my machines except for all the bulbs behind the backglass which I have swapped out for non-ultrabright frosted LEDs on many games. Stay with a shade of white to avoid color bombing.

I guess it is good to think about reducing the fuse size if you’ve really reduced the load. Just want to make sure the fuse is the weakest link. Don’t want any wires or traces burning up on the boards.

I can’t recall hearing of any LEDs failing shorted but on these older Williams have had to replace lots of lamp sockets. Many of those loosen up and cause shorts. Smaller fuse soul just open sooner if that occurs.

As long as the fuse pops before the wiring it really doesn't matter incandescent or not. I tend to gravitate towards smaller fuses in home environment though.

Operators I'm sure have different criteria in regards to fusing.

Operator replacement lifetime fuse.

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That is just like the fuse that was in one of the holders in my Asteroids Deluxe monitor board when I bought it. Luckily the 1N400x fuse downstream acted as the secondary fuse protecting the rest.

May as well buy the full collection!
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** I use the audio/visual auto alerts mostly.

Love it!

Hope to never find one of these in a pinball machine.

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What a great source of information here! Thanks Vid for all the guides!

I'm fixing up my parents old Scorpion pin and am having some troubles. Anyone here have some suggestions?

I replaced all of the caps and reflowed most of the connectors on the board. I added fuses at the bridge rectifiers and swapped the tip42 transistors with the ones Vid recommended as well as swapped the connected resistors with 0-ohm ones. I was going to buy a new 40 pin interconnect but decided to just go ahead and buy the new mpu/driver combo from rottendog - https://www.pinballlife.com/rottendog-williams-system-3-to-6-mpudriver-combo-board.html I'd rather not give myself too many headaches as this is the first pin i've tried to service.

Before the board gets here I wanted to make sure the power board was up and running and i've gotten a few strange readings. 3j2 and 3j3 should read 28v but i'm getting ~40vdc from the backbox. 3j1 should read 18v but i'm getting 22v. Does this sound like a faulty bridge rectifier? What else should I probe to find the culprit of the bad voltage readings? When I plugged it in for the first time to see what it did, the solenoid fuse blew and I don't get any of the GI lights running. After swapping the fuse with a new one, it blew again shortly after trying to boot so I'd hate to damage the new board when it comes in the mail.

Any ideas?

Nope both are completely normal the voltage tends to read high. Bad bridge would blow one of those new fuses you just installed.

Solenoid fuse likely blowing because there's a shorted transistor on the driver board.

Copy! I'll go do another once over of the driver board. I am just worried about pushing too much power into the new board when it arrives and blowing something else

I got the new MPU/Driver combo board from rottendog today. Plugged it in and BAM it works! How exciting! I'm sure the problem with the old board had something to do with the ic's. Now I get to do the fun stuff like rebuilding some flippers and cleaning contacts for switches. Does anyone here have any good diagrams for the wiring in the cabinet? I've noticed a few loose wires and am having trouble finding their homes.

So I've been working on a TriZone (system 6) and troubleshooting why it will not boot.

I have no LED activity at all. I've confirmed a good 5V at test point 9, as well as a good 5V on pins 8 & 35 on the CPU chip (IC1). I moved onto the chip that drives the LEDs, IC2. I can manually light the LEDs by applying 5V, so I know they are good. Does IC2 do anything else besides drive the LEDs? Would it prevent the game from booting?

There is no battery damage on the boards, and I currently have no batteries in it. I know on System 4 boards that I have worked on, they were able to run without batteries. I also have the original ROM and PROM chips in it. Are those known to fail? I'm leaning towards buying a new set of ROM chips but I really want to avoid just shotgunning parts at this point.

Things I've done:
-Confirmed 5V and 12V sources are good
-Replaced all Scanbe sockets
-Re-flowed all connectors on MPU and driver board
-Double checked that the ROM and PROM chips were in the correct locations
-Using an O-scope, i confirmed that I have activity on all legs of the CPU, PIA, RAM, ROM, and PROM chips, as well as activity across the 40 pin connector.
-Using an O-scope, checked the test points on the MPU against the test point readouts in the schematics. (Those are all good).

You are correct about the batteries. They're only needed to retain settings and scores when the game is shut off.

It may help to download the Pincoder software for free (The first 6 tests will help you narrow things down):

https://pincoder.ca

and go through the documentation for each of the tests to get a better understanding of what's going on. There are ROM images also that you can use to run the tests if you have a few chips and chip programmer. If not, you can purchase an adapter that comes preloaded with Pincoder ROMs for all Williams system 3, 4, 6, 6a, and 7 pinball machines.

You can find the adapter at the top of the menu on the website, and also here:

https://pincoder.ca/index.php/2020/07/10/adapter-2020-06-23-0506/

Sell your old boards online!

Did you replace the 40-pin connector on both boards? If it has never been replaced that really needs to be done to ensure it is reliable.

As far as not booting are any of the PIA chips, processor, or 5101 chips AMI brand? Those have high failure rates. If so I would start with the 5101 chip then the PIA chips. If I run into an early board set with those I’ll pull them all out to test and then put in sockets.

Just fixed a non booting machine due to a bad AMI 6821 on the driver.

Thanks for the advice. 40-pin connector is done. I'll double check the PIA, processor, and 5101 chips to see if the AMI brand. Good to know to start with the 5101 if it is an AMI. I'm also going to buy some new 2716 Eprom chips, a burner, and just burn new roms. There have been other times I've needed roms and I really just need to bite the bullet and buy a burner. I'll use it again for sure. Any experience with the $60 LAQIYA TL866Ⅱ burner on Amazon? It seems well rated.

Check the 5101 no matter what brand it is. The CPU and PIA are suspect if AMI brand.

The TL866II is a handy unit and well worth the price. The logic chip test function works good and shows what pins have failed on a chip if just a single gate is bad so you know what part failed. Has trouble with some open collector chips so it may flag those bad when they are not. I use a different tester on those.

In regards to EPROM chips that programmer works well for reading most EPROM chips and to verify against know images. As far as programming replacement chips it depends. Some of the newer low voltage EPROM chips and programmable devices are ok. However chips like the 2716 no and would not trust it to properly program those or any older device that needs 21V or 25V. There are mods that are supposed to help but I just use an older programmer for those early devices.

So that TL866II is a good device that I like and use but you have to understand and work within its limits.

What do I need to look for a replacement AMI Processor and PIA chips?
Mike

Best ones would be the replacement 6821 chips from Western Design Center available from Great Plains Electronics. Too many fakes of the Motorola chips to recommend a source for those.

My 5V went south on Blackout last night, bummer! Have a EZ board on order.

Mouser still has LM323K in stock.. for $68!