(Topic ID: 207343)

Black Knight, what ails thee? Diagnostic switches, game start issues


By solarvalue

2 years ago



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  • 20 posts
  • 8 Pinsiders participating
  • Latest reply 2 years ago by steveopdx
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#1 2 years ago

Hi All,

I've got some issues with Black Knight.

It boots up into attract mode and I can add credits but it won't start a game. Nothing happens when I press the diagnostic switches.

There is continuity from the blue and green wires on the coin door diagnostic switches to the connector in the head.

With 1J4 disconnected, I have tried momentarily grounding 1J4 Pin 3 to 1J4 Pin 2 which gets the machine into the display test, I can then cycle through the display numbers by repeating this. I also have tried momentarily connecting 1J4 Pin 3 to 1J4 Pin 4 but nothing happens. Does this mean there is a cold solder joint at 1J4 pin 4?

Are there any other tests I could try to narrow it down?

#2 2 years ago

Bad 40-pin connector between the CPU and driver. All sorts of open/cold solder joints at the .156" connectors. A great place to start is this thread:

https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6

#3 2 years ago

Just to let everyone know, this game was working before and the boards have all been gone through and tested not too long ago, so they should be mostly good.

Is it possible to remove the MPU without removing the driver board from the game? I mean, can you just undo the top two screws on the MPU and wiggle it out from the interconnect or do you have to take both boards out before separating them?

#4 2 years ago
Quoted from solarvalue:

Just to let everyone know, this game was working before and the boards have all been gone through and tested not too long ago, so they should be mostly good.
Is it possible to remove the MPU without removing the driver board from the game? I mean, can you just undo the top two screws on the MPU and wiggle it out from the interconnect or do you have to take both boards out before separating them?

The MPU sits in a u-shaped channel behind the driver board. You will have to at least remove the screws holding both boards, then you could separate the MPU and remove it.

The issue sounds to me like one of the chips for the switch matrix lines on the upper right corner of the driver board is bad.

#5 2 years ago

I bet it's not "seeing" all 3 balls. Go to switch test and check/clean all the trough switches.

Edit: didn't see the door switch not working part.

#6 2 years ago
Quoted from dothedoo:

The MPU sits in a u-shaped channel behind the driver board. You will have to at least remove the screws holding both boards, then you could separate the MPU and remove it.

Ok, thanks, I'll try that.

#7 2 years ago

Hmm...this problem miraculously fixed itself. The switches are back now, we'll see if it lasts. I'm going to start a new thread with the next problem. Thanks to all who contributed.

#8 2 years ago

The switches in the upper trough often need adjusting. If there are balls there at the start of a new game that could be culprit.

#9 2 years ago

OK, this problem is back: game boots into test mode, will go into attract mode if I flip the switch on and off quickly. Diagnostic switches do not work, game will not start.

Any other ideas or tips on how to remove the CPU board?

#10 2 years ago

If the game is booting into audits, you have a bad battery or bad RAM on the CPU board.

Reflow the solder on the diagnostic switch connector on the CPU board or replace the header pins entirely. If that's been done, replace the IDC connector with a new crimp on style connector.

#11 2 years ago
Quoted from Schwaggs:

If the game is booting into audits, you have a bad battery or bad RAM on the CPU board.

I've changed the battery, where is the RAM on the CPU?

#12 2 years ago

It's to the left of the 2 PIA chips positioned on the right side of the cpu board. I screen capped an image of the cpu board and drew an arrow pointing to the 5101 RAM chip. You may want to replace it with an NVRAM chip so you can eliminate batteries entirely.

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#13 2 years ago
Quoted from solarvalue:

I've changed the battery, where is the RAM on the CPU?

Did you carefully inspect the battery socket to make sure the contacts are not corroded? With the game off, measure the voltage between pin 8 and 22 on the RAM chip to make sure you have 4.5 to 5V

#14 2 years ago
Quoted from Schwaggs:

Did you carefully inspect the battery socket to make sure the contacts are not corroded?

Yep, the board has a cell-type battery socket and battery and the socket is relatively new.

I'll check those voltages and report back.

#15 2 years ago
Quoted from Schwaggs:

With the game off, measure the voltage between pin 8 and 22 on the RAM chip to make sure you have 4.5 to 5V

How are the pins numbered? The one with the green dot is pin number 1 and then you count anti-clockwise, right? If so, I've got 2.6V. Does that mean the chip is bad?

#16 2 years ago

Well, it seems that everything is working again. It may be that the RAM chip was a bit loose in its socket. We'll see if it lasts.

#17 2 years ago

OK, so it didn't last. The game started playing up again. I replaced the RAM chip with a new one from Great Plains Electronics. Everything works now, even the diagnostic switches which I was surprised about.

One thing to note is that I bought 5 x 5101s from Great Plains. When I put the first one in, the game wouldn't boot at all, so some of these chips might be bad.

#18 2 years ago
Quoted from solarvalue:

One thing to note is that I bought 5 x 5101s from Great Plains. When I put the first one in, the game wouldn't boot at all, so some of these chips might be bad.

These chips are VERY static sensitive. If not careful handling them they can easily be damaged.

#19 2 years ago
Quoted from solarvalue:

OK, so it didn't last. The game started playing up again. I replaced the RAM chip with a new one from Great Plains Electronics. Everything works now, even the diagnostic switches which I was surprised about.
One thing to note is that I bought 5 x 5101s from Great Plains. When I put the first one in, the game wouldn't boot at all, so some of these chips might be bad.

You might have a bad socket there. Old single wipe sockets don't last forever.

3 weeks later
#20 2 years ago

I have a Black Knight with the exact same problem.
Not sure if my fix will work for you but see if it does.
I was working on my Black Knight and had a ball in the shooter channel so I took it out and put it in my pocket. Turned on the machine and the symptoms were just like yours.
Realized I had the 3rd ball in my pocket and put it in back in the drain hole. Turned it on and everything started working. I had no idea the game does a check for 3 balls when it turns on. There might be 2 in the upper deck ball lock and 1 at the bottom. Whatever the combination there has to be 3 balls in the machine at all times or it won't start a game. It will do everything short of letting you hit the Start button.
I also was given extra balls with my Flash game so I put one in the Black Knight. Turns out it was a smaller size and thr kicker would not stop trying to eject the ball into the shooter channel. I had to turn the game off and physically remove the ball.
Also don't add more than 1 ball to Flash. It freaks out if there is more than 1 and will keep trying to add a ball to the shooter channel.
Hope that helps!

P.S. - Your backglass looks amazing!

20180129_204526 (resized).jpg

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