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?

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?

Ok, thanks, I'll try that.

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.

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?

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

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.

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?

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.

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.