(Topic ID: 329180)

Stern Monopoly - coil 26 keeps cycling, will not finish power on

By caseyj374

1 year ago


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  • 14 posts
  • 3 Pinsiders participating
  • Latest reply 70 days ago by caseyj374
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#1 1 year ago

I have a Stern Monopoly pin that just started during gameplay having one of the coils cycling. Turned off the pin, restarted it, and now wont start after the cpu screen, (goes to blank screen), and the coil keeps cycling for # 26 (electric company). The following has been tested/replaced:

- New coil
- New switch
- New switch that is in line with that coil
- New diodes for both

Here's video of it happening:

Anyone ran into this before / any thoughts?

#2 1 year ago

The suspect thing is not so much the coil activating, it's that the game doesn't come on.

Here is the link to the Pinwiki article about Stern Whitestar CPU's that don't boot:

https://pinwiki.com/wiki/index.php/Sega/Stern_White_Star_Repair#Power_Problems

Battery acid (alkaline) is the usual cause of these machines having problems, so open your backbox and look very carefully at the batteries and the board around the batteries for any hint of creeping battery acid (alkaline) damage.

Then look at your LED's for power (the front door has a little white 'nub' switch that you'll need to pull out in order to get all your power LED's. Make sure you have all your LED's lit up for all your voltages.

The ribbon cable between the CPU and the power board can be a source of problems, so shut off your game and re-seat it.

Let us know about the battery acid (alkaline) possibility, and we'll be able to help you further.

#3 1 year ago
Quoted from PinRetail:

The suspect thing is not so much the coil activating, it's that the game doesn't come on.
Here is the link to the Pinwiki article about Stern Whitestar CPU's that don't boot:
https://pinwiki.com/wiki/index.php/Sega/Stern_White_Star_Repair#Power_Problems
Battery acid (alkaline) is the usual cause of these machines having problems, so open your backbox and look very carefully at the batteries and the board around the batteries for any hint of creeping battery acid (alkaline) damage.
Then look at your LED's for power (the front door has a little white 'nub' switch that you'll need to pull out in order to get all your power LED's. Make sure you have all your LED's lit up for all your voltages.
The ribbon cable between the CPU and the power board can be a source of problems, so shut off your game and re-seat it.
Let us know about the battery acid (alkaline) possibility, and we'll be able to help you further.

Thank you for the reply - this is a rottendog board, that has the coin-sized lithium battery. I replaced the battery, but it was fine, and nothing leaking from it. The rottendog board came in the system when I bought it.

I did reseat the ribbon cable, thinking that would cause it as well.

I next thought it would be a switch thats stuck and possibly burnt a transistor, but When I do a switch test, looking at the switch matrix grid, it shows every switch on line 2 as being open (Pg DR4 in the manual).

Also something to keep in mind that I am an IT guy - I can fix computer hardware, but when it comes to this.. i'm not an electrical person. I had someone helping me that has worked on pin's in the past, thats how we were able to check switches, replace switches, etc. but then he gave up and couldn't figure out where to go next.

#4 1 year ago

To help you further, can you tell me just a bit more about what is happening?

When you turn the game on it goes to display version, then game ID (the cpu has booted to show the first screen) and then the game goes blank display. This is shown on the video. (Thanks for the video!)

Does the display stay blank, or does the game eventually go into attract?

At this point, can you go into the menu by pressing the menu buttons?

And in the menu, can you go to diagnostics, technician alerts?

What is the game telling you is the problem in the technician alerts?

A couple of things:

When a transistor for a coil is shorted (or the coil shorts and shorts out the transistor) it will pull in, with a fairly loud hum. If you hear that when you power on a pinball, shut power off, and fix the problem before you have a burnt coil wrapper, or burnt boards.

A coil tap, tap, tap as the pinball first activates is the CPU thinking that a ball is stuck (because it sees some problem with a switch) and it's activating the coil associated with that switch to try to get the ball clear. The switch status will be visible in the test menu.

If the game is 'crazy' and it's doing something irrational, like, the switch is NOT thinking that a ball is stuck, but it's activating the coil as if it was... well, the first thing I do is a factory restore (just in case, this isn't the problem in 49 out of 50 situations, but it's easy to do...)

Then I suspect some switch is still the problem. I make sure the balls are all registering in the trough, and that the game HAS all the balls it needs. I go through the ball trough test. I replace the LED's on the optical switch boards in trough (because it's such a common point of failure, and all games this age I suspect the LED's are no longer as strong as they need to be... this doesn't solve my problem, but any time I've got a problem with games of this age it's something I'll do...)

So, the game has all it's balls, you don't have a trough problem, you don't have a switch problem. The switch related to the coil that is being activated by the game is working perfectly.

Is the coil getting power because of a short circuit from somewhere other than it's driver transistor? Like, the wire for the coil return is connected to a flash lamp circuit, and when the flash lamp is flashing the coil is activating? (Very unlikely in this level of technology, but it was something to look for in the System 11 Williams games). A quick look at the wiring to the coil, just to eliminate any weird short circuits is something I'd do... but I really doubt I'd find anything.

In theory, you could have a board problem chip failure doing this, but I've never seen anything like this on a whitestar board.

Let us know what you find... particularly if the game stays on a blank screen and never goes to attract mode.

Thanks!

1 week later
#5 1 year ago
Quoted from PinRetail:

To help you further, can you tell me just a bit more about what is happening?
When you turn the game on it goes to display version, then game ID (the cpu has booted to show the first screen) and then the game goes blank display. This is shown on the video. (Thanks for the video!)
Does the display stay blank, or does the game eventually go into attract?
At this point, can you go into the menu by pressing the menu buttons?
And in the menu, can you go to diagnostics, technician alerts?
What is the game telling you is the problem in the technician alerts?
A couple of things:
When a transistor for a coil is shorted (or the coil shorts and shorts out the transistor) it will pull in, with a fairly loud hum. If you hear that when you power on a pinball, shut power off, and fix the problem before you have a burnt coil wrapper, or burnt boards.
A coil tap, tap, tap as the pinball first activates is the CPU thinking that a ball is stuck (because it sees some problem with a switch) and it's activating the coil associated with that switch to try to get the ball clear. The switch status will be visible in the test menu.
If the game is 'crazy' and it's doing something irrational, like, the switch is NOT thinking that a ball is stuck, but it's activating the coil as if it was... well, the first thing I do is a factory restore (just in case, this isn't the problem in 49 out of 50 situations, but it's easy to do...)
Then I suspect some switch is still the problem. I make sure the balls are all registering in the trough, and that the game HAS all the balls it needs. I go through the ball trough test. I replace the LED's on the optical switch boards in trough (because it's such a common point of failure, and all games this age I suspect the LED's are no longer as strong as they need to be... this doesn't solve my problem, but any time I've got a problem with games of this age it's something I'll do...)
So, the game has all it's balls, you don't have a trough problem, you don't have a switch problem. The switch related to the coil that is being activated by the game is working perfectly.
Is the coil getting power because of a short circuit from somewhere other than it's driver transistor? Like, the wire for the coil return is connected to a flash lamp circuit, and when the flash lamp is flashing the coil is activating? (Very unlikely in this level of technology, but it was something to look for in the System 11 Williams games). A quick look at the wiring to the coil, just to eliminate any weird short circuits is something I'd do... but I really doubt I'd find anything.
In theory, you could have a board problem chip failure doing this, but I've never seen anything like this on a whitestar board.
Let us know what you find... particularly if the game stays on a blank screen and never goes to attract mode.
Thanks!

Thank you for the message - sorry for the delay, I was trying a few different things and went as far as to replace the CPU and Display chips (as checking the CPU chip, it was so brittle that the legs just fell off). So now, when I fire up the pin after replacing those and checking wiring to the coil, I get the same result, however, now the big red light in front of free parking is now flashing on top of the coil still firing. And, I now get an error stating that there is a coil malfunction for the coil that is firing. (Coil #26)

I also forgot to mention that this is not an original whitestar board - the original board has been replaced with a rottendog board. I ran the switch test mode and it is showing the trough switches are working as expected, optos are working as expected, and still giving me that the whole line across the same #26 is having issues. So I haven't progressed much (except for now the red light is flashing). Yes, the game stays on a blank screen except now I get the error about the coil malfunction.

I have not reset the settings to default yet, I'll go try that now. (I'm assuming because I replaced the CPU chips that it would clear those settings anyway, but maybe not).

#6 1 year ago

Also, I do not hear a hum when firing the game up. I just did the factory reset, and didn't give me much difference. However, running the switch test, I'm now showing a bit different switch open popping up than before. I've attached the switch matrix test, (the LED screen is fine, i think its how i was taking the photo)- but the boxes on the left (going vertical) were not lit up like that before changing out the CPU/Display roms.

IMG_6117 (resized).jpgIMG_6117 (resized).jpg
1 week later
#7 1 year ago

Bump for more eyes

1 month later
#8 1 year ago

Bumping again....

#9 1 year ago

Thank you for the picture of the switch test.

The entire Row2 is showing as a solid block. That means that the game thinks that all those switches are activated.

The switches involved on Row 2 are:

4th coin slot on the front door
Railroad Ramp Switch
Middle Top Lane (B) Switch
Electric Company Switch
Bank Opto 2
Lower Right Pop Bumper Switch
Upper Right Pop Bumper Switch
Left Return Lane

These are all connected to the White-Red wire.

They are connected to the CPU on Connector 7, pin 8.

Coil #26 is the Electric Company, so it would be expected behavior, if the Electric Company Switch was saying it was activated, for the coil to activate to clear the ball it thinks is resting on the switch. So that solves the mystery of Coil #26 popping all the time.

The question I'd like answered, is, do we have a board problem.

So, go into switch test, and pull Connector 7 at the top of the board towards the right corner. If the line of switches stays on, the problem is the board.

If the line of switches goes off, then something is wrong somewhere on the White/Red wire. This would likely be the wire touching something that it shouldn't. If the problem is the White/Red wire, go to every switch mentioned above, and carefully look to see if there is anything obvious. Follow the White/Red wire, and see if it's pinched, or some switch terminals are mangled and touching.

Let us know what you find, and don't worry about the weird red light right now, once the switches are working properly you can look into further problems.

1 month later
#10 11 months ago
Quoted from PinRetail:

Thank you for the picture of the switch test.
The entire Row2 is showing as a solid block. That means that the game thinks that all those switches are activated.
The switches involved on Row 2 are:
4th coin slot on the front door
Railroad Ramp Switch
Middle Top Lane (B) Switch
Electric Company Switch
Bank Opto 2
Lower Right Pop Bumper Switch
Upper Right Pop Bumper Switch
Left Return Lane
These are all connected to the White-Red wire.
They are connected to the CPU on Connector 7, pin 8.
Coil #26 is the Electric Company, so it would be expected behavior, if the Electric Company Switch was saying it was activated, for the coil to activate to clear the ball it thinks is resting on the switch. So that solves the mystery of Coil #26 popping all the time.
The question I'd like answered, is, do we have a board problem.
So, go into switch test, and pull Connector 7 at the top of the board towards the right corner. If the line of switches stays on, the problem is the board.
If the line of switches goes off, then something is wrong somewhere on the White/Red wire. This would likely be the wire touching something that it shouldn't. If the problem is the White/Red wire, go to every switch mentioned above, and carefully look to see if there is anything obvious. Follow the White/Red wire, and see if it's pinched, or some switch terminals are mangled and touching.
Let us know what you find, and don't worry about the weird red light right now, once the switches are working properly you can look into further problems.

Thank you for this!! I'll be checking this next - so here's an update - I purchased a new rottendog board, brand new and upon swapping the board, it started working. However, it lasted about 5 power on and power off's then it went exactly back to what it was doing. It seems as if something is being blown on the MPU in those times - I played it a good couple hours, turned it off, gf turned it on and it started right back doing it again. I put the original board back in, and still same issue so its blowing something on the board now.

Does that make any sense at all? I now wonder if it is something with the driver board sending too much power back onto the MPU?

1 month later
#11 10 months ago
Quoted from PinRetail:

Thank you for the picture of the switch test.
The entire Row2 is showing as a solid block. That means that the game thinks that all those switches are activated.
The switches involved on Row 2 are:
4th coin slot on the front door
Railroad Ramp Switch
Middle Top Lane (B) Switch
Electric Company Switch
Bank Opto 2
Lower Right Pop Bumper Switch
Upper Right Pop Bumper Switch
Left Return Lane
These are all connected to the White-Red wire.
They are connected to the CPU on Connector 7, pin 8.
Coil #26 is the Electric Company, so it would be expected behavior, if the Electric Company Switch was saying it was activated, for the coil to activate to clear the ball it thinks is resting on the switch. So that solves the mystery of Coil #26 popping all the time.
The question I'd like answered, is, do we have a board problem.
So, go into switch test, and pull Connector 7 at the top of the board towards the right corner. If the line of switches stays on, the problem is the board.
If the line of switches goes off, then something is wrong somewhere on the White/Red wire. This would likely be the wire touching something that it shouldn't. If the problem is the White/Red wire, go to every switch mentioned above, and carefully look to see if there is anything obvious. Follow the White/Red wire, and see if it's pinched, or some switch terminals are mangled and touching.
Let us know what you find, and don't worry about the weird red light right now, once the switches are working properly you can look into further problems.

I pulled connector 7 at the top of the board and the line of switches stays on. It appears to follow the board, I purchased a new board and put it in, and gave me the same thing after 5 or so power on/power off cycles. Should I be looking at a new power board next?

4 weeks later
#12 9 months ago

Bumping to see if anyone has suggestions.

#13 9 months ago

Inspect the switch wires carefully along their entire length, could be it shorted to a higher voltage source and that is frying something.

6 months later
#14 70 days ago
Quoted from dr_nybble:

Inspect the switch wires carefully along their entire length, could be it shorted to a higher voltage source and that is frying something.

I inspected them all the way through, and I do not see anything causing a short. There was a ground strap that was unhooked from a speaker that was pushed down inside the cabinet, so I reattached that to the speaker (the owner before me did a speaker mod), but I didn't see that it was touching anything when it was unhooked. I bought a new power driver board but have not put that in yet, after reading farther that I'm concerned that it wont fix the problem. I havent had much time lately to work on this and now I have some time to try and get this fixed. Any other thoughts?

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