90s Williams - Start/Ball Launch not triggering (Demolition Man)

[Jason Catrine]

Hi all,

Looking for a bit of help. The issue is, various switches inside the cabinet are not triggering - Ball Launch, Left Handle Button, Start button and Plumb Bob Tilt.



So from looking in the manual it appears my issue is with the green-brown cable. I've checked the green and brown cable with my muiltimeter and I appear to be getting a reading from all the above mentioned switches (11, 12, 13, 14 in above pic) The issue only appears to affect the green-brown cable in the cabinet switches as when i test the green brown cable on the playfield switches for Left Outlane/Inlane etc then these switches work fine (15, 16, 17 in above pic).

Some background to this:

Paul has very kindly helped me get this far, but I dont want to keep bugging him so decided to write this post and ask the rest of you for suggestions. I've tested the cpu board by jumping from the connectors - eg Ball Launch - placed jumper wire from J207-1 to J209-1 and it triggered the ball launch on the matrix tests.

The CPU board is also a new Pinsound one that I purchased a few months ago. The power driver board has been away getting repaired over the past few months too. When I bought this machine, it was a project - batteries had leaked so I had no idea what worked and what didn't. After I put the new CPU board in the Start and Ball Launch buttons kind of worked - you had to press them a couple of times before they registered, so something was iffy. I then noticed the game was having power issues and resetting for no reason - could be sitting in attract mode and it would bounce. Hence why I sent the power board away.

Like I said, multimeter shows voltage through all of the cables going to the affected switches. Wires all appear to be connected properly (as far as i can see). So my troubleshooting continues and i'm looking for options as to what i can try next. Should add i'm already out my depth here and needed help to get this far so i'm hoping for any other simple things to try first as anything major is probably gonna be outwith my skills.

Thanks,
Jason.

 

[Jason Catrine]

From checking voltage on green/brown cable on ball launch and start button, its around 3-4v and moves to around 11.3v volts when i press the buttons in. Dunno if that helps at all but trying to give as much info as I can - literally clutching at straws,

 

[AlanJ]

Do you have continuity from that wire in the cabinet back to the board in the backbox. If the playfield switches are working but all the cabinet ones are not then I’d suspect it’s not getting there. Does it go through any connectors? If so check those

 

[Paul]

Paul has very kindly helped me get this far, but I dont want to keep bugging him

Very kind of you - I really dont mind though!!

 

[Jason Catrine]

I’ll need to try and see if i can cobble something together to try and get the leads on my multimeter long enough to reach from the start button back to the connector in the backbox.

Would the fact I’m getting power down to the end of the cable at the start button end not prove my cable is ok?

 

[Paul]

I’ll need to try and see if i can cobble something together to try and get the leads on my multimeter long enough to reach from the start button back to the connector in the backbox

Disconnect both ends of the pair. Make sure that you have the same pair at the top as at the bottom. Put a short on between the pair at one end, then measure both at the other....

 

[Jason Catrine]

Have i done this right? Connected the white and green from ball launch button together with a wire like this….


And then set multimeter to continuity and i cant get probes inside the end of the connectors but I’m touching pin 1 on j209 and j207 connectors like this….

Should that work by probing it there??? I’m using black lead in similar fashion on pin 1 of connector alongside the one in pic - just cant hold them both in place and take a pic at the same time.

Getting 0 on multimeter display doing it this way so wondering if i need to go look for other small cables to push into the end of the connector blocks so i can stick probes onto them, or should how I’m touching that pin1 on the connector block work and its proving I don’t have continuity?

 

[AlanJ]

You’ve proved mpu is working ok by jumping the row and Col to simulate a switch closing and that worked.

It can really only be wiring into the cab.

the manual explains how the switch circuit works. The Col goes low and if a switch is closed then it brings the row low which is recognised as a switch close by the mpu.
If the wiring is faulty on the column is staying high for some reason then you’ll never get a switch registering. Need to check that col wire is strobing low and that the row wires are connecting back to the mpu board ok.

 

[Jason Catrine]

@AlanJ is this message below what you mean? Col green cable is low and then voltage goes up when i press the button

From checking voltage on green/brown cable on ball launch and start button, its around 3-4v and moves to around 11.3v volts when i press the buttons in. Dunno if that helps at all but trying to give as much info as I can - literally clutching at straws,

 

[AlanJ]

Measuring voltages isn’t really telling you anything, because the columns are (or should be) strobing high and low very quickly.

 

[AlanJ]

This explains what’s supposed to be happening.

Do the playfield switches on the same row as the start button work ok in switch test?

 

[Asiapinball]

Your cabinet switches go through j212 on the cpu. The ones you are probing on your pic are the playfield switches. You need to be checking continuity from j212 to the coin door interface board which is located front left wall of cabinet. Then on from the small interface board to the switches themselves. My guess is a loose green wire at the interface board.

 

[Asiapinball]

There should also be continuity between j212 pins and the corresponding ones on j206/7 and j208/9. If you did your cpu board switch tests on j206/7 and j208/9 you may also like to do same on the j212 connector (4 white and 2 green so 8 switches to test) just to make sure board connections to j212 are working.

Edit : j206 or j207 which are in parallel. And j208 or j209 which are in parallel.

 

[Asiapinball]

Interface board connectors j3 which goes to j212 on cpu and j6/7/8/9 each of which go to varios switches.