Which game?
Does it have magnets?

So I removed the wires and tested the BR, it tested as good. In attract mode, I measured the AC voltage at the BR at 29V and the DC voltage at 35V. My understanding is that it should be 25.5VAC and about 28VDC.

It's Scorpion

That's fine, transformers are a relatively imprecise item so it's normal for them to not be spot on.

The instruction booklet calls for a 15A SB fuse for F4 on the power supply.
That would mean the before the bridge rectifier will also have to be 15A SB.
I think it's rather high, but logical.
An 8A fuse would get hot during game play and will eventualy blow at one point.
Nothing wroung, just too low for 4 flippers.

Sorry to butt back in but on my stellar wars with the missing transformer. I got new transformer in, new bridge rectifiers, voltages all test good at power supply output. I have 4.9 volts coming out and if I plug the mpu and/or driver board in that drops down to about .5 volts

Ok I found my first issue and fixed it, weak solder joint on the 12v on power supply. I fixed that and now TP1 on mpu has 12v and 9 has 5v as required. The top led cane on on the mpu.

I took the driver board off and soldered on a new 40 pin plug and touched up solder on male side. Reconnected and now both leds come on with nothing on score displays. I don’t have any batteries in yet

Did you replace both sides of the 40 pin? Leaving the old, round pins on the male side isn't good.

You need to reflow solder or replace each and every header pin on every board.

When you have the game on and there is nothing on the score displays, look at different angles into the displays to see if there is any orange glow at all. If not, CAREFULLY measure the high voltage supplies to the displays.

So before I changed to 40 pin, I would only have the top led, if I cycled the power switch fast, the displays did come one for a bit then off, and the led changed to the bottom one. Now both leds come on. I did reflow solder on all of the male pins

Both LEDs on indicated a CMOS failure. But until you replace the male pins of the 40 pin, you are chasing a ghost.

Reflowing Solder on them is not good enough

Ok, when I first power on the game both leds flash then go off, no displays. If I cycle the power switch both leds come on and stay on. No displays.

I removed the driver board from the mpu but left the board plugged in just pulled away from mpu and the relay on the driver board clicked and all the solenoids on the playfield energized for a second then off

This chip on the driver board also looks like it has been resoldered and not a very good job of it

1CF86E5A-CBE8-4140-836C-C4BA804C8C49 (resized).jpeg

Gonna have to send my boards off... I noticed the rom chips heating up

You don't need to cut any existing cabinet wires to install fuses

I think he is referring to the dual bridge board that a lot of people use. You do need to chop off the ends of the wires for that.

Nice to see someone make one with the .250" terminals to match what is on the original bridge.

That should go right in place of the original bridge and looks like a good solution. I usually just install a standard fuse holder nearby, plug one of the wires from the transformer into that, then make a short jumper with .250 terminal to plug into the original bridge. In-expensive and accomplishes the same thing.

One thing to watch out for is many games have those connections soldered after they were plugged in. You have to heat them up with the iron to melt the solder in order to pull them off.

I've added the fuses on PinBot, Blackout, and soon FirePower.

It looks like a nice option and I prefer not hacking up the original wiring. These look like an easy drop in replacement.

No need to hack the wiring, you simply move the wire from the bridge to the fuse and add a short jumper wire from the fuse to bridge.

IMHO this is a mandatory upgrade as detailed by Williams and should never be undone, machines were catching fire. All machines made after a certain point came with the "upgrade" from the factory.

I say "upgrade" as it should have been on the machine day one.

This is a modification that "Should" have been designed into the game originally. It is a safety design that is built into any circuit with short condition possibility that has high amperage. Worrying about if it is OEM is not a consideration here. Just needs to be done.

On top of that it is an easy modification that requires no design change per-se.

Totally agree but it really doesn’t take much extra effort at all to make it looks like it belongs. These new bridge modules look like a nice clean easy way to do so. I’d use these.

Yes, it is a clean design. The only issue with this is normally the terminals to the BR's are soldered. Removing soldered terminals like these is not an easy task. With that said it is not hard to cut the wires and put new terminals on.

Still a must do update either way.

They weren't soldered from the factory. If they are soldered you just put your soldering iron on the lug and pull with your free hand.

...and stand back when the solder flies!

If they were not soldered then it is super easy.

I added fuses to the bridges in Grand Lizard and the terminals were soldered. I don't know about system the older systems. I still need to add fuses to Road Kings.

Fwiw, you may want to consider replacing the bridges at the same time you install the fuses. They're cheap enough, and it'll save you the trouble of replacing them down the road if they're the original 40 year old bridges.

I can personally attest to the effectiveness of those added rectifier fuses. I installed mine in my BK over 10 years ago, and about 3-4 years ago the coils stopped working...just in time for our annual Halloween party, literally an hour before the party began. Found the rectifier fuse blown due to the original rectifier going bad. Can't say for certain it would have started a fire, but it certainly *could* have it the fuses weren't there.

Also, the spade terminals were soldered onto the rectifier lugs on my game. It appeared factory, but i can't say for sure.

My were soldered as well, not uncommon in my experience from the factory

Where did you see that Williams suggested this mod? I can't find any evidence they suggested it. On top of that, they didn't add a fuse in front of bridges until all the bridges were moved onto power boards, sometime in the middle of the system 11 era in the late 80s. Early sys 11 still had no fuses on the offboard bridges.

Not saying it isn't a mandatory upgrade, it is for sure especially considering the low cost and high protection it provides.

Was in pdf form a few years ago, scan of the original technical service bulletin.

I have read it as well in a service bulletin.

Working on a Vids Guide to upgrade my power supply of my William's Blackout.

A few questions came up related to finding the right parts online so links appreciated:

1. What is the part numbers to the two bridge rectifiers in the backbox? I've got my fuse holder but Thought I might replace them in addition to adding the fuses.

2. What is a good replacement for the fuse holders on these System 6 boards. I'm only finding ones for PCBs with two small prongs that attach to the PCB. My power supply looks like they are pressed into the slot then soldiered?

3. What spacing/style are the pins the wiring harnesses connect to (9 Pin, 12 pin, 6 pin and 15 pin) I see various sizes and "square pin" options. So I'm confused? I've only just always re soldier them but noticed my 15 pin has some bent pins so decided I just want to replace all.

The one and only https://www.greatplainselectronics.com/

You can't go wrong with Ed G-P-E

What parts specifically are the items mentioned in the questions I think was what the question was he had.

Also GPE is often out of stock on things in my experience.

You can also check
Arrow.com
Digikey.com

And a couple more I can't recall at the moment.
If Ed doesn't have what I need my next stop is digikey.com

Fuse clips: https://www.greatplainselectronics.com/proddetail.asp?prod=1A1907-03
Bridge Rectifier: https://www.greatplainselectronics.com/proddetail.asp?prod=GBPC3504L
.156 (3.96mm) pitch header pins (cut to size): https://www.greatplainselectronics.com/proddetail.asp?prod=26-48-1245

I don't really like the look of the cut to size header pins so I order specific size KK Series connectors from Mouser but that is much more expensive and no better (only cosmetic).

It seems that the style used on the boards isn't available anymore. The closest you can get is one with two vertical lugs

Thanks

I'm trying to help a friend replace his blown transistor. However the previous owner overheated the transistor leg holes and now the 3 metal rings are gone (where the transistor legs should be soldered). So now the solder won't stick/attach to the transistor holes. What's the best way to fix this? Jumper the legs? Is there a rivet or something similar to replace the metal around the holes?

Yes. But....

Delicate work and you have to have the right tools including a really good soldering pencil and high quality solder. This video....

...is not exactly as you describe the condition of your board, but should give you an idea. If you've never done it before you should get some help from someone who has the tools. Your Weller gun will not do this job.

OTOH, Vid may have some better suggestions. He always does.

///Rich

Interesting, thank you
I'll have to check Great Plains and see if they have any of these eyelets.

Recently I’ve run into an odd issue on a System 3 MPU in a Williams Hot Tip machine. The board is extremely clean and recently had a new 40-pin connector set and new DIP sockets installed.

The board doesn’t always boot. If I shut off the game and turn it back on it usually just comes up an plays normally without issues.

Read about the factory mod to the reset section of the MPU to remove c27, r30, and r40. Then add a 10k resistor. This board already has this mod done and appears factory.

Any other known reset mods for the System 3 boards or items to check?

If you've done all of that, I'm assuming you already proofed out the power supply?(check 5v output, reflow header pins as needed and maybe recap it)

I completely went through the driver and power supply as well. I'm going to go back over all the boards on the bench again just to be sure and will check the resistors and transistors in the reset circuit in case any are bad. I typically don't have to touch those but don't want to assume they are ok since it isn't consistent when booting.

After that I will probably try my spare power supply and driver to see if that happens to clear things up. May pop in a different 6800 CPU since that is an AMI brand and I've run into issue with their PIA chips. Seems odd that it is just the initial booting of the machine. Once it is up it runs fine.

I did install a Weebly NVRAM module in it and could try going back to a regular 5101 RAM to see if that makes a difference.

Also curious if anyone has tried to do bypass some of the bus drivers like the change in the later System 6 boards and if that applies and would be a good thing to do on the earlier boards like the system 3-4

It's looking like it may be just a flaky AMI 6800 CPU chip. Swapped it out and it seems better. Need to do additional tests tomorrow evening.

I witnessed first hand the non fused bridge rectifier wire melt down on a Williams shuffle. Replaced and it is working now. I will definately take the time to upgrade my games and alert some locals that they should do the same as well.

Just wanted to thank Vid again for this awesome guide!

I have been dipping my toe into the early William's solid state pool and while familiar with Data East, William's has just enough of their own quirks that this guide has been invaluable reference. My Blackout and Space Shuttle are just humming along thanks to what has been gone over here.

I was playing Laser Ball today and I double flipped and the game froze. Reading Pinwiki I see two different pieces of advice, but I'm not quite sure what it is referring to when it says "rebuild the solenoid power circuit" in 6.13.7. That is the lower info with the blue tick mark.

The upper info is from 6.7, and I can do that too, but need to know what to check/replace for the solenoid power circuit.

Reset (resized).jpg