(Topic ID: 184304)

TECH: No switches working Stern Whitestar (Monopoly)


By schudel5

2 years ago



Topic Stats

  • 12 posts
  • 4 Pinsiders participating
  • Latest reply 2 years ago by schudel5
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#1 2 years ago

I work on games that are located in a barcade that is only closed on Mondays. Anyways they have a Monopoly that has been fine ever since it was put there about 6 months ago. About two weeks ago it started acting up and would not recognize when a ball drained unless you shook the machine a bit. I went last Monday and noticed in switch edge test that the connector for the opto board in the trough was cracked. Reflowed the solder and it worked fine.

Then last weekend get a call that it's not working again; so I figure it's going to be something in the trough. So turn the game on and it says "4-balls missing...searching for balls" when there are all 4 balls in the trough. The game continually fires the lock kicker about 10 times then shows a coil error message and just sits there.

So I go into Portals then select diagnostics but then the coin door switch wont let me go any farther. I can't select the switch test with the buttons as it wont let me advance anymore. I checked all the fuses (I didn't think that was the issue, but tried anyways, and they were fine) and I reseated all the connectors in the backbox.

I head back Wednesday, but the bar will be open and it will be tough to do anything then, other than simple things, until next Monday.

Any ideas what it could be or anything that I'm overlooking?

If I could get into switch edge test it would be easy. If I can't get into switch edge test how can I use a diode test rig to test rows/columns?

#2 2 years ago

Any battery leakage?

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#3 2 years ago

The board is super clean. But next Monday I'll pull the CPU and see underneath what it looks like. Could be something going on that I don't see from the top side.

#4 2 years ago

maybe something is shorted on the switch row with the coin door switches so you cant enter portals? does anything else work (attract sounds with flipper buttons, start button etc)

Also never had it on a whitestar, but on WPC boards Ive shorted eg coil voltages to the switch matrix and fried the isolation chip - may be worth looking into

#5 2 years ago

I can push the button to enter portals, then get into diagnostics but when the screen comes up with switches, coils, flashers, previous, quit, etc. It won't move or select. Using the flipper or start button to move or select doesn't work either. Not being able to enter past that I can't check anything. Without detecting balls in the trough it won't boot up properly. When it finally does, you can't start a game because it starts searching for balls again. I was able to successfully add credits, but that's it.

#6 2 years ago

Replace the RAM. That will get you back to factory settings if there's something in memory causing this. It will also of course take care of it if the RAM is bad.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#7 2 years ago

Good idea. I was thinking of pulling the RAM and game ROMs off the CPU to see if that does anything first. If it doesn't, I will replace the RAM.

#8 2 years ago

Put in new 6264 RAM and same thing.

I can get into Portals then no further past that. The coin door buttons are non-responsive after entering Portals.

#9 2 years ago

Hmmm...my next step would be to swap the CPU ROM and PAL with known good, and/or swap out the CPU, to isolate it to that board or not.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

2 weeks later
#10 2 years ago

Ok. Found Q2 and Q5 were bad on the cpu so replaced those with new 2n3904 transistors. Now with the connectors removed and diode across CN5 and CN7 every switch works when tested.

Put the connectors in and have an issue with one row. The right slingshot registers as right slingshot and start button. The start button registers as start button and right slingshot. The #4 trough opto doesn't register at all. They are all on the same row (white/blue wire).

I'm going to dig into it but one thing I can't find is the diode for the start button. Does anyone know where the diode for the start button is located on Monopoly? It's not on the switch.

#11 2 years ago
Quoted from schudel5:

They are all on the same row (white/blue wire).
I'm going to dig into it but one thing I can't find is the diode for the start button. Does anyone know where the diode for the start button is located on Monopoly? It's not on the switch.

From what I can tell by looking through the manual and the pics I have of the CPU, It looks like the diode is somewhere under connection CN7 on the CPU. D400- D407. It has to be one of those. The manual does not make it very clear but that's where it lead me. The diode is a 1N4148 , it's a signal switching diode.
If I'm wrong hopefully someone will clear it up.

1 week later
#12 2 years ago

So after replacing Q2 and Q5 on the CPU board, all switches worked with the exception of the #4 trough opto. Pulled the trough opto board and found a surface mount 2N3906 at Q2 was bad. Replaced it with thru hole device and the game started up and played!

On ball 3 the game got confused and wouldn't play right. Went into switch edge test and the 2N3906 was bad again. Replaced it again. Played a couple balls and the game got confused again. This time Q5 on the CPU board was bad again. Changed it and played a couple balls when the game started having issues again with Q5 going bad again.

At this point I stopped changing transistors. All voltages are fine. 12V is fine. Power to the game is fine.

What would cause Q2 and Q5 on the CPU (column drive transistors) along with Q2 on the trough opto receiver board to keep going bad? Why just those 3 and nothing else. There are optos on those rows/columns but there are others too in the game. Any advice would be greatly appreciated.

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