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More switch matrix woes (Data East Jurassic Park)
- Thread starter lozzauk
- Start date
Edited because I've done a bit of digging myself.
Our Data East Jurassic Park when the T rex is down is triggering a switch matrix problem.
T rex up
T rex down
Right scoop trough
Right VUK
Not used
I noticed that there's a gap on switch 59 on column 8.
This lines up with trough 3 which is disconnected because the tab is broken off (which is a separate problem but one I know how to fix but need a new part) I can't help but think this isn't a coincidence!
I'm suspecting a short in column 2 because these switches are normally closed as the machine has 6 balls installed.
Machine is at my girlfriends so won't be able to check but does this seem likely that I've got a short on one of the trough switches? (they are far too easy to knock on this game!) Maybe trough switch 2 as per my messy diagram. I think this would be why it only happens when T rex is down?
Obviously it's all theory until I'm back by the machine.
Doesn't seem to make sense that manually operating the t rex bottom switch manually it seemed to function but perhaps I was mistaken and I need to go back to the active switch test. It's difficult to activate that switch and look at the screen at the same time.
What's the best way to confirm my theory? Test without the balls installed? Desolder the common from switch 2 in the trough? (Some of the switches feel like the plastic has gone brittle so I wouldn't be surprised if they're failing internally...?)
Also what's the part code for the roller switches in the trough? 180-5119?
Our Data East Jurassic Park when the T rex is down is triggering a switch matrix problem.
T rex up
T rex down
Right scoop trough
Right VUK
Not used
I noticed that there's a gap on switch 59 on column 8.
This lines up with trough 3 which is disconnected because the tab is broken off (which is a separate problem but one I know how to fix but need a new part) I can't help but think this isn't a coincidence!
I'm suspecting a short in column 2 because these switches are normally closed as the machine has 6 balls installed.
Machine is at my girlfriends so won't be able to check but does this seem likely that I've got a short on one of the trough switches? (they are far too easy to knock on this game!) Maybe trough switch 2 as per my messy diagram. I think this would be why it only happens when T rex is down?
Obviously it's all theory until I'm back by the machine.
Doesn't seem to make sense that manually operating the t rex bottom switch manually it seemed to function but perhaps I was mistaken and I need to go back to the active switch test. It's difficult to activate that switch and look at the screen at the same time.
What's the best way to confirm my theory? Test without the balls installed? Desolder the common from switch 2 in the trough? (Some of the switches feel like the plastic has gone brittle so I wouldn't be surprised if they're failing internally...?)
Also what's the part code for the roller switches in the trough? 180-5119?
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Asiapinball
Site Supporter
I have always taken the view that you should fix all known problems first. I would focus on the issues you have with switch 3.
There is an incredibly useful write up here which should give you all the pointers you need to diagnose.
It's unlikely you will have multiple switch failures at the same time. Switch matrix problems usually end up being one shorted wire or component be it a diode switch transistor etc.
There is an incredibly useful write up here which should give you all the pointers you need to diagnose.
It's unlikely you will have multiple switch failures at the same time. Switch matrix problems usually end up being one shorted wire or component be it a diode switch transistor etc.
Thanks. I'm really just trying to avoid ordering a part and then finding I should have thought of something else first. I have some basics like diodes, rubbers etc but not much in the way of switches.
I know I need to replace trough switch 3 and the machine is not going to be playable until I do so.
I suspect I need to replace trough switch 2 as well (or least check round it that it's not shorted) since it's the only way I can see that when T rex is at the bottom all of column 8 triggers (where there's a corresponding switch on row 3 closed) and about 3 of these switches just feel like the plastic is ready to crumble.
What would you recommend? Replace trough switch 2 and 3 and go from there?
I know I need to replace trough switch 3 and the machine is not going to be playable until I do so.
I suspect I need to replace trough switch 2 as well (or least check round it that it's not shorted) since it's the only way I can see that when T rex is at the bottom all of column 8 triggers (where there's a corresponding switch on row 3 closed) and about 3 of these switches just feel like the plastic is ready to crumble.
What would you recommend? Replace trough switch 2 and 3 and go from there?
Asiapinball
Site Supporter
Pinball Lamp or Switch Matrix Troubleshooting -
Your pinball switch matrix acting up - Multiple switches turning on when only one should - Hit one switch and four go off? This is how to fix it.
homepinballrepair.com
This is the website.
Asiapinball
Site Supporter
Read up on the website link first. You can probably work out what the issue is from there. You seem to be keen to work it out logically. The guide will help. You should be able to test the switches and diodes with a dmm but you will need to desolder diodes. Some data east have connectors on the green wire so you can just pull them off which is really helpful for testing.
Asiapinball
Site Supporter
This video is old but good.
Thanks for the links.
That video is particularly good and actually explains it in the way that isn't a total headscratcher for someone like me who knows just enough about electronics to be dangerous.
Based on those I think I probably do have a short across trough switch 2. I'll have a look (probably Friday) and update the thread. And of course I need to replace switch 3, that's a given.
Sadly the trough switches are all soldered onto metal that's even cheaper feeling than the original fuse holders did
That video is particularly good and actually explains it in the way that isn't a total headscratcher for someone like me who knows just enough about electronics to be dangerous.
Based on those I think I probably do have a short across trough switch 2. I'll have a look (probably Friday) and update the thread. And of course I need to replace switch 3, that's a given.
Sadly the trough switches are all soldered onto metal that's even cheaper feeling than the original fuse holders did
Asiapinball
Site Supporter
I would be checking the diodes on switch 58 and switch 10 first.
Asiapinball
Site Supporter
Looks like you got to that conclusion yourself about a minute before I posted. 
I had to play part of the video twice but it makes sense. The trough switches are my least favourite part of underneath the playfield. They seem unnecessary vulnerable to being knocked (and these look like they have been in their time, but it's been reliable...!)Looks like you got to that conclusion yourself about a minute before I posted.
Appreciate the help and patience with a relative newb like me. I'll be sure to update the thread when it's fixed. I confirmed the part code in the manual at least.
Have a good evening.
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Asiapinball
Site Supporter
The old style trough switches always get beaten up the worst. It was no wonder that there was a shift to optos. I find it incredible that the trough switches of the 1990s have lasted so long but quality was generally better back then particularly the cherry brand switches.
The diode for trough switch 2 (switch 10) was just about touching the ball trough. Thus shorting row 2, onto column 2 and every closed switch on column 2 that was also closed reporting erroneous closures for the column 8 once t rex down (row 2) was triggered.
The same would have almost certainly have happened if I triggered another switch on row 2 on another column.
The short was almost impossible to see even when I was looking only at this switch.
Cleared that and only fault now is pinball missing so will replace trough switch 3 and the game will be up and running again. Should be an easy fix once I get the part.
Thanks for the help and also helping me get a grasp of the switch matrix.
Asiapinball
Site Supporter
Dm me your address and.i will pop the switch you need in the post. Used but good working order.
Thanks. Would be much appreciated but entirely up to you.
