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(Topic ID: 115542)

Firepower display issue with one segment


By Spybryon

5 years ago



Topic Stats

  • 33 posts
  • 8 Pinsiders participating
  • Latest reply 5 years ago by barakandl
  • Topic is favorited by 7 Pinsiders

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#1 5 years ago

I am having a problem with the bottom segment on all the displays. In the master display board schematics, it's segment "d".

On player 1, player 2, and the credit / match, the segment is always on. (In the pictures, please keep in mind player 1 and player 2 look the same, in some pics the backglass blocks view)

On player 3 and player 4, the segment is always off.

I am thinking there is something wrong on the master display board? Based on the symptom, is it possible to identify a certain component or bad IC that would cause this?

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#2 5 years ago

With segment issues the first thing you have to do is look at the 10K resistors on the MDB.

For segment D on the P3 & 4 displays that's R11 and for the MDB, P1 and P2 its R4 (though all 10K resistors should be checked).

For your P3 and P4 displays, I'd guess it's a resistor problem. But with the locked on segments on the other three displays, that's more likely a problem with the 7180 at IC9. To confirm, disconnect all the slaves and power the machine on. If the segment is off on the MDB, hook each one of the displays back up one at a time. If the segment locks on with one of the slaves hooked up, you have a bad glass. If the segment is locked on the MDB with nothing hooked to it, it's either a bad glass or a bad 7180. Diagnostic info is on Pinwiki. If it's the 7180, you will be hard pressed to get a replacement.

Edit: Yes you can get a replacement from Arcade Chips - $20:

http://www.arcadechips.com/product_info.php?products_id=79

viperrwk

#3 5 years ago

Thanks Viperrwk!

I did take a look at the master display board. I took a picture, there are some burnt resistors on the far right side of the board!

IMG_20150118_203320 - Copy.jpg

Someone worked on those 2 in the past. I guess they doubled up 2 resistors in parallel in order to use lower wattage resistors?

I checked with a voltmeter and found:

The rightmost pair is reading open.

The second from the right pair, it matches the rest of the resisors to the left.

What should I do next to fix the display? Replace those 2 pairs with correct resistors?

#4 5 years ago

Replace the burnt resistors with the correct 10k 1/2 watt resistors.

If they burn again, you may have a bad IC or glass. Often replacing the resistors fixes the problem.

1 month later
#5 5 years ago

I just replaced R11 and R12 on the master display board with the correct 10k 1/2 watt resistors.

After turning on the game, R11 immediately starts getting hot and smoking. I turned off the game as soon as it started smoking.

R12 is OK and did not overheat.

I was looking at the schematic, and I am wondering if R11 burning up means something is wrong with IC10? What should I check into next?

#6 5 years ago

first you need to look at the displays themselves before you go nuts attacking the MDB chips. Disconnect the two suspect displays and power up. the resistor should not get hot. if it does, disconnect all the displays and power up. still hot? then it's a chip. If not hot, it's a display glass problem. Connect displays one at a time and power up until you find the display that is causing the problem. I find the issue usually is display glass related.

#7 5 years ago

Good idea to narrow down the display causing the problem.

I disconnected player 3 display, and then R11 stopped burning up.

I have the rest of the displays connected now (P1,P2, and P4). On those displays, they work except for segment "d" is stuck on all the time. Segment "d" is the lowest horizontal segment.

#8 5 years ago
Quoted from Spybryon:

Good idea to narrow down the display causing the problem.
I disconnected player 3 display, and then R11 stopped burning up.
I have the rest of the displays connected now (P1,P2, and P4). On those displays, they work except for segment "d" is stuck on all the time. Segment "d" is the lowest horizontal segment.

On every single display or just 3 and 4? R11 is involved with Segment "d", the lowest most horizontal segment for players 3 and 4. The display issue may have damaged the master display board.

How advanced are you in testing? The 4543 chips are decoders. There are four inputs and a bunch of outputs pulsing at logic level (5v) to turn on the displays. Segment "d" output is p12 at both 4543 decoders. With the game in display test, check pulses there and compare them to the other segments. Check the four inputs to the decoders as well for pulsing(open connector if not). If everything looks good there, replace the UDN IC. If you have a dead output replace the 4543 chip (or lift a leg and check again). The UDN chips take the logic level inputs and ramp them up to high voltage to drive the displays. You can do more checking at the high voltage UDN chips, but it is hard to recommend probing around 100v in tight quarters.

#9 5 years ago

Hey display-master barakandl,

Where is that great online reference for displays, that says:
If it's a segment, it's most likely X
If it's fuzzy on all cells it's most likely Y

-mof

#10 5 years ago

This should help understand i think.
Untitled-2.png

#11 5 years ago

You should also move P4 to P3 and see if the problem is still there. It could be a short in the actual display glass, or the circuitry going to that display. Need to figure out which it is.

#12 5 years ago
Quoted from barakandl:

On every single display or just 3 and 4? R11 is involved with Segment "d", the lowest most horizontal segment for players 3 and 4. The display issue may have damaged the master display board.
How advanced are you in testing?

I can probably handle that level of testing assuming it can be done with an oscilloscope.

Segment d is stays lit on every single display including the master. Currently 3 is disconnected.

What I also noticed is, for a second after turning on the game, all displays are normal. Then after a second, segment d comes on and stays on.

There is also a bunch of wires that have been connected between player 3, and 4 wiring harnesses near where it connects to the master display board. This was done before I got the game and I have no idea why it was done. Let me post a picture but I haven't mapped out what was done.

I am thinking of mapping out what those wires are cross connecting to figure out what was done before?

#13 5 years ago
Quoted from johnwartjr:

You should also move P4 to P3 and see if the problem is still there. It could be a short in the actual display glass, or the circuitry going to that display. Need to figure out which it is.

Sure I can try that as well.

#14 5 years ago

OK, took a look at the wiring today. Someone has connected an extra wire from 4J7 pin 2 to 5J1 pin 9 and daisy chained it to 5J2 pin 9, 5J3 pin 9, and 5J4 pin 9.

4J7 pin 2 is +100vdc (input on Master display board)
5J1 pin 9 is Anode keep alive (input on P1 display)

Why would someone hook up this extra connection?

I removed it, and didn't notice any difference.

#15 5 years ago
Quoted from johnwartjr:

You should also move P4 to P3 and see if the problem is still there. It could be a short in the actual display glass, or the circuitry going to that display. Need to figure out which it is.

I plugged P3 display into the master display Player 4 output, and the resistor didn't fry. Also all the resistors were normal temperature after leaving it on a few minutes. So it seems like resistor frying problem is on the master display board itself, on the Player 3 output.

So it seems like I have atleast 2 issues:
1) resistor frys on master display board when a display is plugged in to P3 output.
2) stuck on segment d on every display including credit/match

What should be next step?

#16 5 years ago

I am not sure what's the next step here and looking for any input.

I just unplugged all displays, P1-P4, and the segment "d" is still stuck on the master display board display. Then when I plugged in displays P1,P2,P4 , segment "d" is still stuck on all of those. (I am afraid to plug anything into P3 until resistor stops frying).

I put the game in display test. Using a voltmeter, I checked IC5 and IC8, which are MCI4543 chips.
I can see that pins 9-15 are changing between 0 and 5 volts as the display test progresses.

Any ideas?

#17 5 years ago

If the decoder outputs are correct, moving up and down all the way, time to look at the high voltage side.

The bad display could have fried both UDN chips when you where swapping displays around as a test. You can tell if the high voltage chip is working with your DMM on volts dc. Put the lead on working segments and note how your meter reads. You will get an average number, maybe 60volts or so. Check to see if that one segment pin gives a reading different than all the other segment pins.

Be very careful probing around 100v, i have a hard time recommending doing so. It might be easier/safer to do this at the 10k resistors.

#18 5 years ago

I just tested IC9 and IC10 which are UDN7180 chips.

First, I put the game in display test mode.

On IC9, pin 2 is input and pin 17 is output pin. I can see the input pin 2 cycling between 0 and 5 volts as expected. However the output pin 17 is stuck at -97 volts.

On IC10, it's the same. Input pin 8 is cycling between 0 and 5 volts. Output pin 11 is stuck at -97 volts.

I tested a few of the other output pins on IC10 (which is easier to get to). Those output pins were cycling between -27 volts and -97 volts.

So it seems like the UDN7180 chips are the cause of the problem?

What about the burning resistor at R11? Is it the same root cause, bad 7180 chips?

I know these 7180 chips are hard to come by now. I have some display boards from my Bugs Bunny which are missing the actual display glasses. In my Bugs Bunny, I replaced the displays with new LED boards. I don't know if those chips are good because the display glasses were removed prior to me acquiring the game. Is it worthwhile trying to harvest these UDN7180 chips? I'd probably have to get help from a friend who has a better desoldering tool to get those chips off the board intact.

#19 5 years ago
Quoted from Spybryon:

I just tested IC9 and IC10 which are UDN7180 chips.
First, I put the game in display test mode.
On IC9, pin 2 is input and pin 17 is output pin. I can see the input pin 2 cycling between 0 and 5 volts as expected. However the output pin 17 is stuck at -97 volts.
On IC10, it's the same. Input pin 8 is cycling between 0 and 5 volts. Output pin 11 is stuck at -97 volts.
I tested a few of the other output pins on IC10 (which is easier to get to). Those output pins were cycling between -27 volts and -97 volts.
So it seems like the UDN7180 chips are the cause of the problem?
What about the burning resistor at R11? Is it the same root cause, bad 7180 chips?
I know these 7180 chips are hard to come by now. I have some display boards from my Bugs Bunny which are missing the actual display glasses. In my Bugs Bunny, I replaced the displays with new LED boards. I don't know if those chips are good because the display glasses were removed prior to me acquiring the game. Is it worthwhile trying to harvest these UDN7180 chips? I'd probably have to get help from a friend who has a better desoldering tool to get those chips off the board intact.

The UDN chips are probably bad if the input moves up and down yet the output is stuck at -100. The bad display is probably frying that segment output.

You can test the segment resistors in circuit since they are in series. I think they are 10k. Measure across them and replace as needed. These resistors go OPEN often. 1 watt resistors fit okay, use at least 1/2w.

I would set the offending display aside, maybe give it a good visual check for problems like a solder splash or broken pins.

I buy master display boards at pinball shows specifically for harvesting these high voltage chips off of them. You can get remarks on ebay. I tested a few and the remarks have been working okay for me, use them at your own risk.

Andrew

#20 5 years ago

This is interesting, I just found out there is a set of unused input / output pins on the UDN7180s!

http://www.firepowerpinball.co.uk/2ya/extras/FP-extra-6.html

So I maybe able to fix my problems by using the extra unused pair. I confirmed in the schematics that pin 1 / pin 18 is available.

Quoted from barakandl:

I would set the offending display aside, maybe give it a good visual check for problems like a solder splash or broken pins.

I wish I knew if one of the displays are bad or not. I am going to check out Display 3 closely and buzz it out with a meter for shorts. However it's really strange because R11 was burning up when P3 display was hooked up to P3 output. However, when I moved connector so that P3 display was hooked up to P4 output, no resistors were burning up. That's why I am confused if I have a bad display on my hands or not.

I am thinking, once I clip the output leg of IC10 at pin 11, and see if there is a short to ground or not. If there is, it points to bad display glass, right?

#21 5 years ago
Quoted from Spybryon:

This is interesting, I just found out there is a set of unused input / output pins on the UDN7180s!
http://www.firepowerpinball.co.uk/2ya/extras/FP-extra-6.html
So I maybe able to fix my problems by using the extra unused pair. I confirmed in the schematics that pin 1 / pin 18 is available.

I wish I knew if one of the displays are bad or not. I am going to check out Display 3 closely and buzz it out with a meter for shorts. However it's really strange because R11 was burning up when P3 display was hooked up to P3 output. However, when I moved connector so that P3 display was hooked up to P4 output, no resistors were burning up. That's why I am confused if I have a bad display on my hands or not.
I am thinking, once I clip the output leg of IC10 at pin 11, and see if there is a short to ground or not. If there is, it points to bad display glass, right?

That would require doing one of two things. Cutting and jumping on the master display board or building an adapter board. Both ways i would say it spring for a new $5 IC and wait a week or two if it comes from chiner

Lifting an output leg can confirm the IC is bad.

#22 5 years ago

OK, just got done working on IC9 which is the UDN7180 for Player 1 and Player 2. I had to cut the leg off of the chip on Pin 2 (the input for segment d). Unfortunately, I could not do the same cut on Pin 17 which is the output. I couldn't make the cut because the display glass is in the way. So I went ahead and cut the trace on the back of the board going from Pin 17 to R4. Then I had to make a jumper on the back of the board from Pin 2 over to Pin 1 to start using the unused pair. Next I had to make a jumper from Pin 18 over to R4. After all this, I plugged the master back in.

When I plugged it in, the master is working perfectly! Next I plugged in Player 1 and Player 2. Those are also working correctly in the display test!

So, the next thing to do is the same modification to IC10. First, I want to make sure that Player 3 and Player 4 displays are OK. The reason I need to check these displays is that I am worried about the burning resistor problem at R11. Was it buring up because of bad IC10 or because of a bad slave display?

I am wondering how I can test the display glasses for problems? I want to make sure that I can fix it once and for all.

#23 5 years ago
Quoted from Spybryon:

the master is working perfectly!

Now, you are the master!

Well done, Dr. Frankenstein!
-mof

#24 5 years ago
Quoted from Spybryon:

OK, just got done working on IC9 which is the UDN7180 for Player 1 and Player 2. I had to cut the leg off of the chip on Pin 2 (the input for segment d). Unfortunately, I could not do the same cut on Pin 17 which is the output. I couldn't make the cut because the display glass is in the way. So I went ahead and cut the trace on the back of the board going from Pin 17 to R4. Then I had to make a jumper on the back of the board from Pin 2 over to Pin 1 to start using the unused pair. Next I had to make a jumper from Pin 18 over to R4. After all this, I plugged the master back in.
When I plugged it in, the master is working perfectly! Next I plugged in Player 1 and Player 2. Those are also working correctly in the display test!
So, the next thing to do is the same modification to IC10. First, I want to make sure that Player 3 and Player 4 displays are OK. The reason I need to check these displays is that I am worried about the burning resistor problem at R11. Was it buring up because of bad IC10 or because of a bad slave display?
I am wondering how I can test the display glasses for problems? I want to make sure that I can fix it once and for all.

Nice job making it work!

A bad slave display could kill the UDN chip for sure. See if you can detect and shorts or odd readings around the associated pins on the suspect display glass.

#25 5 years ago
Quoted from barakandl:

Nice job making it work!
A bad slave display could kill the UDN chip for sure. See if you can detect and shorts or odd readings around the associated pins on the suspect display glass.

Thanks!

I just buzzed out all pins on Player 3 display and Player 4 display with meter.

Started on pin 1 and did all pins, so every possible pin combination is covered.

On Player 3 display, between pin 5 and pin 9, it reads around 1400 - 1500 ohms. This corresponds to segment "d" and anode keep alive.

On Player 4 display, all pins, including between pin 5 and pin 9, read infinity.

So I guess Player 3 display is bad and shouldn't be used anymore?

#26 5 years ago

I just finished working on IC10 and cut the bad legs and pryed them up. I pried up leg 8 and leg 11. Then I ran a jumper on the back side of the board from Pin 8 to Pin 1. Ran another jumper wire from Pin 18 to Pin 11. This allows the unused pair of pins to be used on the UDN7180 chip. (Pin 1 and Pin 18 were originally unused on the chip).

While I was at it I replaced the burned R11 with a new one and mounted it slightly off the board for better heat flow.

I am thinking that Player 4 display is bad, so I did not plug it back in. I started a new thread about it here:

https://pinside.com/pinball/forum/topic/this-system-3-6-display-is-definitely-bad-right#post-2313625

I moved my Player 4 display over to Player 3.

Now, Player 3 display is working correctly!

I will post some pictures tomorrow of the jumpers on IC9 and IC10 just for reference.

#27 5 years ago

You are evolving into a display-master!
-mof

#28 5 years ago

Spybyron, forgive me - have a question totally unrelated to your display issue. Couldn't help but notice the back glass on your Firepower - it looks great. Is that the original? A reproduction? Mine is just OK, could use an upgrade & was just curious. Thanks.

#29 5 years ago

Thanks. It is the original one. The backglass is in decent condition. I have seen better though. There's a few scrapes on the back side. Looks like they came from rubbing the cables or displays, not sure how it happened.

#30 5 years ago

That backglass is really nice. Mine is terrible, missing a whole blue wing off of the ship. But I just upgraded to Xpin displays because of my segment issue. I'm not as handy with circuitry as the posters in this thread. Glad you're getting sorted!

#31 5 years ago

Thanks Geocab!

I wonder if you want to try to fix your original displays? If you like working on boards it's not that bad.

As I learned, if you have just one segment out, first thing check your resistors, it could be simple. If not, it maybe the UDN7180 chip. Since there's an extra input / output available you can use that if needed.

Here's a few pictures of the jumpers I did on the back of the master display board, and the displays working. (Not sure when I took the pictures of the displays some segments were invisible to the camera, but could be seen with the eye, it must have to do with the display frequency)
IMG_20150316_201541 - Copy.jpg

IMG_20150316_201514 - Copy.jpgIMG_20150316_201451 - Copy.jpgIMG_20150316_202245 - Copy.jpg

IMG_20150316_202257 - Copy.jpg
#32 5 years ago

I did replace the resistors to no avail and narrowed it down to either the glass on the master or the 7180. At that point I said I'll just deal with it and see if I can get a replacement master display. Finally I got an Xpin replacement set and I'm happy. I did a playfield swap last year so I figured the expense was worth it. Just need a better backglass.

#33 5 years ago
Quoted from Geocab:

I did replace the resistors to no avail and narrowed it down to either the glass on the master or the 7180. At that point I said I'll just deal with it and see if I can get a replacement master display. Finally I got an Xpin replacement set and I'm happy. I did a playfield swap last year so I figured the expense was worth it. Just need a better backglass.

Hit me up if you want to sell the master display and used original glass.

Andrew

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