(Topic ID: 164495)

Switch Matrix Problem


By jrawlinson_2000

3 years ago



Topic Stats

  • 16 posts
  • 9 Pinsiders participating
  • Latest reply 3 years ago by jrawlinson_2000
  • Topic is favorited by 2 Pinsiders

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IMG_20160722_070346_(resized).jpg
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IMG_20160719_174411_(resized).jpg
jd_(resized).jpg

#1 3 years ago

I am trying to track down a switch matrix issue on a JD, before I burn it as firewood!

Having researched switch matrix issues, I have managed to draw a rectangle around the ‘rouge’ switches and I think it’s a diode issue, but tracking it down has been thus far been impossible.

What is happening; is when SW18 3 Bank Targets is hit it also activates the SW14 Tilt-bob, also when the SW38 Subway Enter 2 is activated it triggers the SW34 Inside Right Return. Thus making the rectangle on the matrix.

So I have replaced a diode on the first of the three SW18 3 Bank Targets (others tested fine so did not do these), the diode on SW34 Inside Right Return & SW38 Subway Enter 2.
All of the diodes taken out tested fine, so they clearly were not the issue.

Looking over other switches all diodes look to be on the correct way round, added to this I have tested a number in place and the appear fine.

I have put in a known working coin door interface to eliminate the tilt diode and other coin door and front buttons.

SW58 Drop Target ‘E’ is flaky as it flickers on and off, so I plan to reflow the solder. But I did simply disconnect the connector to that board and still had the switch problem.

Some switches in column 1 and row 4 are optos, do these have diodes if so where and how do I test them?

Any other suggestions as to what to do, test or how to work through this issue, its driving me mad!

Cheers

Julian

jd_(resized).jpg

#2 3 years ago

Start by making sure you don't have a board problem, un plug all the switches to the mpu not sure which ones, you'll have to check manual. and then run switch test, all switch's should read as open. optic boards are opposite, they read closed until activated.

#3 3 years ago

what other switches are closed when you get 14 and 34 being triggered by the other ones? (pic of the switch test screen?)

#4 3 years ago

Still stumped on this problem.

I have disconnected the switches going into the MPU and made the connections using a jump wire and the 'faulty' ones work just fine so its not the MPU, here is an image with the connectors off;

IMG_20160719_174411_(resized).jpg

Here is the issue with one of the two faulty switches, you can see the lower left matrix switch come on the 3 bank target and the tilt-bob half way up on the same column.

#5 3 years ago

There are no diodes for the optos, but there is an LM339 which can go bad and cause random problems. Remove the row and column connectors from the opto board(s) and see if the problem goes away.

#6 3 years ago

During some more fault finding, I used the multimeter in diode / continuity test to see if the row wires were good between switches in row 4 (white & Yellow).

What I found was strange as I would have thought I should get full continuity on the white & yellow wire on all switches and molex connectors going into opto boards and JUDGE opto board in that row, most I did but a few I got .516 which would indicate a diode reading!

Does this indicate a green & white wire on a switch in that row is connected wrongly?

#7 3 years ago

OK a further update;

If I disconnected the J1 connector on the coin interface board and the switch errors do not happen, but plug it back in and I get the two switches firing.

I've tried to narrow it down further with no luck, as disconnecting the other coin interface connectors one-by-one leaving J1 connected the error still happens, so I dont think its a front or side cabinet switch issue like fire, start or supergame.

One thing I did notice is if I plug in J1 from the bottom of the connector so only the lower pins make connection the fault does not happen until almost the last 1 or 2 (top) pins are connected and this is where I notice switch 25 (always closed) kicks in and its when this switch is active I get the issue.

Again I have tried another coin door board and still get the same issue.

All points to this now but I've taken a working one from another JD and get the same issue.

What is switch 24 for? This is in the same row as the 2 erroneous switches that are being triggered.

Any suggestions?

#8 3 years ago

Switch 24 is used so the cpu knows it has 12v power. One thing I did notice is when you have everything plugged in switch 28 shows closed and it's not used.

#9 3 years ago

Can u post a photo of the wiring to the 3 bank targets?

#10 3 years ago

Photo of 3 bank target.

IMG_20160722_210149_(resized).jpg

#11 3 years ago
Quoted from jrawlinson_2000:

OK a further update;
If I disconnected the J1 connector on the coin interface board and the switch errors do not happen, but plug it back in and I get the two switches firing.
I've tried to narrow it down further with no luck, as disconnecting the other coin interface connectors one-by-one leaving J1 connected the error still happens, so I dont think its a front or side cabinet switch issue like fire, start or supergame.
One thing I did notice is if I plug in J1 from the bottom of the connector so only the lower pins make connection the fault does not happen until almost the last 1 or 2 (top) pins are connected and this is where I notice switch 25 (always closed) kicks in and its when this switch is active I get the issue.
Again I have tried another coin door board and still get the same issue.
All points to this now but I've taken a working one from another JD and get the same issue.
What is switch 24 for? This is in the same row as the 2 erroneous switches that are being triggered.
Any suggestions?

It sounds like you narrowed down your problem to switches located after the coin door board. Check the slam tilt switch on the back of the coin door, check the wiring to your plumb bob tilt, and check the wiring and diode on the slam tilt on the bottom of the cab.

#12 3 years ago

Can you check all opto's on the balltrough.
In the video they are all OFF, that would be normal if the balls are located in the trough, but the 'Top Trough' is not ON as well.
Maybe something wrong here. Try disconnect the trough-receiver-board and do same test again.

Quoted from jrawlinson_2000:

What I found was strange as I would have thought I should get full continuity on the white & yellow wire on all switches and molex connectors going into opto boards

Check switches with the Wht-Yel wire 34 and 44, maybe wired wrong.

#13 3 years ago

Sorted!

I posted the issue on a UK pinball forum (www.pinballinfo.co.uk), and a chap said he had had exactly the same issue a while back and it turned out to be 2 molex connectors under the playfield near the deadworld (so lower left) that were incorrectly connected (i.e. swapped over).

http://www.pinballinfo.com/community/threads/judge-dredd-2-switches-firing-at-the-same-time.33824/

You will see in the photo the 2 molex that were plugged into the wrong connectors, simply swapping over these 2 and the switch matrix is fully working.

IMG_20160722_070346_(resized).jpg

#14 3 years ago

So, how did these get reversed? It would have helped if you had started off by giving a better background of this. It is more helpful to say what the history of the machine was before it started to fail. I was going on the assumption that it was working fine and now it doesn't for some reason. AND that you didn't touch anything or change anything before this happened. Bottom line is when troubleshooting it's good to spell out every possible detail BEFORE as well as after. You probably could have saved yourself some time and stress. Just a thought. Glad you got it solved.

#15 3 years ago
Quoted from Catch86:

So, how did these get reversed? It would have helped if you had started off by giving a better background of this. It is more helpful to say what the history of the machine was before it started to fail. I was going on the assumption that it was working fine and now it doesn't for some reason. AND that you didn't touch anything or change anything before this happened. Bottom line is when troubleshooting it's good to spell out every possible detail BEFORE as well as after. You probably could have saved yourself some time and stress. Just a thought. Glad you got it solved.

This is pretty common, and I can relate to the frustration. If it isn't made clear in the beginning I will often ask such questions as "Was it working and suddenly failed, or did you recently aquire the machine?" Sometimes you need to pry out information, not everyone has the troubleshooting mindset.

#16 3 years ago

The machine was 'new' to me and came with this issue.

Just glad someone else had the exact same issue so knew what the problem was, as it would have taken a while to track it down otherwise.

Apparently its common on Judge Dredd as working on Dead World means when its put back together its easy to get these 2 swapped over.

Updating so others may be able to find the solution if they get a machine with this issue.

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