(Topic ID: 246237)

System 11: All comma segments lit on left display. PinLED


By mystman12

9 months ago



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  • 32 posts
  • 10 Pinsiders participating
  • Latest reply 8 months ago by mystman12
  • Topic is favorited by 2 Pinsiders

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#1 9 months ago

This has been an issue with this game ever since I got it. All of the commas are locked on on the left display. I've never really done any board work or anything so I'm not really sure what I should look for. These are Pin LED displays, but I'm not sure if that makes any difference or not. Thanks in advance for any help!

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#2 9 months ago

Is there any way I can swap the two displays to see if the issue is being cause by the display itself or the board? I noticed there's one labeled left and one labeled right, and the right one has another plug on it.

#3 9 months ago

Check for bad connection for the comma signal from the CPU to the display board.

#4 9 months ago

Thanks. I ended up finding the pinout table for the displays in the manual, and it says the comma is board pin #44 and glass pin #80. I'm not sure what that means however... I took the display out to see if I could find a pin with one of those numbers, but I'm not seeing anything that matches the numbers in the manual. Since this isn't an original board I suppose it's possible it doesn't have all the original markings, but honestly I have no idea what it's supposed to look like.

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#5 9 months ago

Those pin numbers are for the glass itself.
You need to trace the wire from the CPU board to the display board.
Actual connectors, pin numbers depend on which game this is for but typical would be CPU J22, pin 26 to display J3, pin 26.
Are you using original ribbon cables? Could be a bad ribbon cable.

#6 9 months ago

What do you mean by "the glass itself"? The only glass I know about is the playfield glass and translite. Sorry if I'm missing something obvious, but I'm a complete noob when it comes to board work.

I found the cable connecting J22 to J3, is there a specific way I should test it? I was able to get continuity between the pin 26 point on the display board and a point on the CPU that traces to pin 26 on J22, so it seems like pin 26 is good on the ribbon cable. As far as I know the ribbon cable is original. Btw, if the ribbon cable was bad, wouldn't both displays have the issue? The same ribbon cable connects to both displays.

Another question, how were you able to determine that pin 26 would be the pin to check when the manual refers to the comma as using board pin #44?

Sorry for all the questions, but thanks for the help!

#7 9 months ago

I’d start by crossing cables to different displays. Then by actually switching cables. This way you can narrow it to one of three things. Before the cable, the cable, or after the cable. In my experience it tends to be before the cable if it’s an entire line on a display. You can use the schematics to narrow it down to a certain pin which should be fairly easy, or you can check each one. But I’d bet the display board itself has a bad solder joint.

Edit: just reread your post and saw it uses one ribbon cable. Still, Same thoughts since it’s a whole line, but my trouble shooting technique is useless.

#8 9 months ago
Quoted from mystman12:

What do you mean by "the glass itself"

The original display was made out of glass, now you have led displays which are plastic.

Quoted from mystman12:

Another question, how were you able to determine that pin 26 would be the pin to check when the manual refers to the comma as using board pin #44?

Look at the pic below.

I would put the display back in and reconnect all the connectors but J-3. Take the ribbon cable that goes from one display to the other and rotate both ends 180 degrees. If this cable is bad the problem will change to some other segment on the display. If it stays the same then you need to contact the manufacture.

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#9 9 months ago
Quoted from GRUMPY:

The original display was made out of glass, now you have led displays which are plastic.

Look at the pic below.
I would put the display back in and reconnect all the connectors but J-3. Take the ribbon cable that goes from one display to the other and rotate both ends 180 degrees. If this cable is bad the problem will change to some other segment on the display. If it stays the same then you need to contact the manufacture.[quoted image]

Thanks for the explanation! I did a 180 on all the display cables and the issue still persists, so that rules out the cable as the cause. I guess the next step would be to determine if the display board or the CPU is the cause of the issue. Unfortunately I don't have any other displays I can try putting in the game in the moment. What should I check from this point?

Edit: I just realized, since the commas are only showing up on one display, does that mean the issue is being caused by the display itself? Like I mentioned earlier, both displays use the same cable (The ribbon cable continues past the plug on the left display and ends at the plug on the right display), but is there any way the issue could be caused by the CPU and *not* light up all the commas on both displays? If not I suppose that does confirm the display itself as the culprit.

#10 9 months ago

Had this happen on my Elvira, the problem is on the MPU.
how much corrosion do you have?

#11 9 months ago

To narrow this down further - need to rule out which board is causing the issue.

The CPU board provides a "DOT" and "COM" signal to the alphanumeric displays.
The DOT = the dot portion of comma, the COM = tail portion of Comma.
As shown in first photo - the tail is lit but the dot is not.
The problem can be at the CPU end or the display end (or could still a bad cable).

Check the CPU board to make sure both DOT and COM are being driven equally.
For starters - check voltage reading at pin 9 of U41 to pin 17 of U41. Best method would be to use a scope to compare both simultaneously but a voltage reading *might* give us a clue.

And as wdennie mentioned - post a photo of the U41 section of the CPU board. That's right in line with the batteries and the mentioned COM and DOT signals pass right under them on it's way to J22.

#12 9 months ago

Here's some photos of U-41. As far as I know there's no corrosion, as the batteries are on an external holder. The chip is dusty, but I don't see any corrosion.

I'll try to measure the voltage later today. Anyone know of a quick guide I can look at so I can make sure I do it properly?

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#13 9 months ago

Looks like there was a bit of corrosion on B2 at the negative end (???). Normally see corrosion at positive end so could be something else. U41 does look clean of corrosion.
Need pix of the SIP resistor/capacitor networks and connector J22 just above the battery holders in photo 1.
If ok -- you'll need to start scoping things out to see where the signal is stopping at.

#14 8 months ago

Here's a couple pics above the battery holder:
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Everything looks alright to me. I guess I'll go ahead and get a logic probe moving forward instead of trying to use my meter.

#15 8 months ago

Yep - you're to that point. Follow the signal from beginning to end and see where it stops (or if it is stuck).

#16 8 months ago

Just got the logic probe set up. I've got no signal coming out of pin 17 on U41. Bad chip?

What I don't understand is, if there's absolutely no signal for the comma, how is the comma segment still working fine for the right display?

#17 8 months ago

I pulled the CPU board out to get a look at the back side, just in case there was anything worth looking at there.

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#18 8 months ago

You really need to pull that battery pack and see what is under there. With this corrosion, there is likely more I would guess.

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#19 8 months ago

Okay, will I have to desolder that in order to remove it? Also, since the signal is failing at U41, which is before anything goes underneath the battery, do I really need to check behind that yet? I'd rather not remove that unless absolutely necessary. Honestly if I got to that point, I'd probably just send the board in for repairs before I did anything myself... Which as of now is looking like what I'll have to do.

Also, I was going through the display test and I noticed a few other issues. The right most period on the left display will not light at all, and the right most period and comma on the right display also will not light. Not sure if that's related, but I figured I should mention it.

#20 8 months ago

Yes you would need to desolder, but it sounds like you are not confident to do that. The corrosion will spread, or at least that is the info I have been told and seems to be the concensus here. I would not leave that board with that on there if it were mine. If you are not getting continuity from u41 to the scr component, you are already going to be sending it off for repair. Anyone who repairs that will pull it off for you.

#21 8 months ago

chrishibler will be happy to look at it for you and get rid of those batteries to install NVRAM. It is a great feeling having a collection of games that are battery free!!

#22 8 months ago

A nice trick I learned from one of my buddies....use a dry paint brush and just brush off the dust off the board. It is real quick and easy.

#23 8 months ago
Quoted from PinballManiac40:

A nice trick I learned from one of my buddies....use a dry paint brush and just brush off the dust off the board. It is real quick and easy.

I just did that a few hours ago... For the second time. I missed a few spots the first time, but this game was so dusty when I got it I don't think I'll ever be able to get it all out.

#24 8 months ago

Sounds like you need a stiffer brush.

#25 8 months ago
Quoted from PinballManiac40:

Sounds like you need a stiffer brush.

#26 8 months ago

You should run the display test and not test the data line in attract or game mode. In test mode each signal will be isolated. You can pause and step the display test by setting the latching switch (the center switch) to "in". Fiddle around with it if you're unsure. Once the test is in "step" mode you can use the "advance" switch to advance. The test will run through the numeric display for all display positions (strobes) then all segments of each individual strobe. Finally it will test each individual segment for all strobes.

You can just let the display test run and if you desire capture a video and upload it. The top "comma" segment is 1J22-26 and the bottom "comma" segment is 1J3-1.

#27 8 months ago
Quoted from DumbAss:

You should run the display test and not test the data line in attract or game mode. In test mode each signal will be isolated. You can pause and step the display test by setting the latching switch (the center switch) to "in". Fiddle around with it if you're unsure. Once the test is in "step" mode you can use the "advance" switch to advance. The test will run through the numeric display for all display positions (strobes) then all segments of each individual strobe. Finally it will test each individual segment for all strobes.
You can just let the display test run and if you desire capture a video and upload it. The top "comma" segment is 1J22-26 and the bottom "comma" segment is 1J3-1.

Oh wow, I didn't realize the commas were controlled by a different cable on each display (I'm assuming by "top" you meant left and by "bottom" you meant right? Mousin' Around has the displays side-by-side instead of stacked). That explains why the issue is only present on the left display.

I don't know if further testing is necessary at this point though. Like I mentioned, my logic probe is getting absolutely no signal on pin 17 of U41 (No lights, no sound), while all of the other pins output something regardless of what state they're supposed to be in. Interestingly it seems like there is continuity between other pins and pin 17 on the chip.

#28 8 months ago
Quoted from mystman12:

Oh wow, I didn't realize the commas were controlled by a different cable on each display (I'm assuming by "top" you meant left and by "bottom" you meant right? Mousin' Around has the displays side-by-side instead of stacked). That explains why the issue is only present on the left display.

I don't have a machine with left/right configuration and I haven't examined which is left and which is right on the bench.

Quoted from mystman12:

I don't know if further testing is necessary at this point though. Like I mentioned, my logic probe is getting absolutely no signal on pin 17 of U41 (No lights, no sound), while all of the other pins output something regardless of what state they're supposed to be in. Interestingly it seems like there is continuity between other pins and pin 17 on the chip.

U41-17 is indeed the "comma" segment for the top (presumably = left) display. If there's absolutely no signal (neither 0V nor +5V) then I don't think it should light up at all but I don't know enough about how the circuit works on the PinLED board that you're using.

Quoted from mystman12:

Okay, will I have to desolder that in order to remove it? Also, since the signal is failing at U41, which is before anything goes underneath the battery, do I really need to check behind that yet? I'd rather not remove that unless absolutely necessary. Honestly if I got to that point, I'd probably just send the board in for repairs before I did anything myself... Which as of now is looking like what I'll have to do.

You should make sure you have the correct continuity from U41-17 to SRC2-9 to 1J22-26. This line runs underneath the battery holder so it is often subjected to alkaline corrosion. You can cut the battery holder off if you don't want to de-solder it. You will need some strong cutters though. If you're going to send the board off for repair make sure the person you choose to do the repair will accept the repair. Often people won't touch a board with the slightest evidence of alkaline corrosion.

Quoted from mystman12:

Also, I was going through the display test and I noticed a few other issues. The right most period on the left display will not light at all, and the right most period and comma on the right display also will not light. Not sure if that's related, but I figured I should mention it.

That never lights up during the digit portion of the test. It should light up in the segment portion of the test for either the strobes or the segments. It has been a while since I focused on that particular portion of the test so I'm doing that from memory. I'm in the process of repairing another System 11B board that has issues with U41 and U25 so once I've got all the correct continuity I'll run the test and verify that what I've written (about the dot and comma for the last strobe) is true.

#29 8 months ago

Following because I (contrary to pinsider above) am a dumbass when it comes to this stuff but enjoy learning.

.... please continue

#30 8 months ago

You don't need to desolder the battery holder.
Just clip it off, being careful to not damage any of the fine traces under it.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#31 8 months ago
Quoted from mystman12:

Also, I was going through the display test and I noticed a few other issues. The right most period on the left display will not light at all, and the right most period and comma on the right display also will not light. Not sure if that's related, but I figured I should mention it.

Quoted from DumbAss:

That never lights up during the digit portion of the test. It should light up in the segment portion of the test for either the strobes or the segments.

I just fixed my U25 issue and I got a board boot. However there's a strobe problem now. Before dealing with that (using the tests to show the problem) ...

I did verify that the software does not appear to illuminate the final display strobe (16) in ANY of the sequence of tests so the dot and comma on that display should never illuminate.

#32 8 months ago

Finally got back to this. There's perfect continuity between pin 17 on U41 and pin 26 on J22, so it's safe to say the trace between the two is good. If anyone still thinks it's worth checking behind the battery holder I'll clip it off, but seeing as there's continuity between those two points I really doubt there's any corrosion back there.

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