(Topic ID: 246986)

Eight Ball Freezes


By Pin_Bob

6 days ago



Topic Stats

  • 6 posts
  • 4 Pinsiders participating
  • Latest reply 3 days ago by barakandl
  • Topic is favorited by 1 Pinsider

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#1 6 days ago

Hi Everyone!

I have a 1977 Bally Eight Ball that I just bought. It was missing the MPU when I bought it and appeared to have been sitting around for many years. I purchased an AllTek ultimate MPU and I installed it according to the instructions. The game will turn on and I can enter the self diagnostics mode with no problems. I was able to get all the feature lamps fixed and I ran it through the solenoid tests. All solenoids work with the exception of the knocker and one chime. The coils on these two are bad and the wires have been cut. I have ordered the coils and transistors for these. I ran the stuck switch test and it shows that switch #2 is stuck. I inspected the switch and it is not out of adjustment. I removed the wires to that switch and the machine still shows that switch is stuck. Figuring this would not stop the game from running (?) I finished the game adjustments and book keeping and attempted to start the game. The intro chimes play fine, the flippers work (switches held closed) but when it gets to about the point where the ball ejects, some spotted lamps light just as the relay on the solenoid driver clicks and the game freezes and the flippers fall. From this point the general illumination lights are lit, some feature lamps are lit (spotted) but nothing else seems to work. Points cannot be scored and solenoids will not work. I try to enter self diagnostics from here but that will not work either. I turn the game off and back on and I get back to where I was with attract mode working (racked balls light up in sequence as normal) but as soon as I try to start a game it freezes again. While frozen, I checked the voltages at all test points on the power supply and solenoid driver and they all seem to be fine. I can also enter self diagnostic mode again.

The switch that diagnostics shows as stuck (#2) has a diode and also a cap across it (I do not see it on the playfield diagram). I was wondering if this switch problem could have something to do with the game freezing?

I did plug the MPU into another game and it works fine in that game. I also tried the memory clear feature but that did not change anything.

Any ideas?

I have also ordered all the pins and connectors to replace all the female connectors going to every board. I have also reflowed the header pins on the solenoid driver board but not the power supply board yet.

Bob

#2 5 days ago

The switch problem might be tilting the game. Does the tilt light come on?

The capacitors on the switches do fail and cause a stuck closed symptom. If the switch is open but the test mode is showing it closed cut one end of the capacitor loose and see if it clears. There is usually a capacitor near the plumb bob tilt or roll ball tilt in the cabinet.

A limitation of the switch test is that it will only show the lowest switch number that is closed. So if a switch matrix problem is making the CPU read switches 2,10,18,26,34 as closed switch test will only tell you 2 is closed because it is the lowest switch number.

#3 5 days ago

Since you removed the switch #2 from the test by disconnecting the row/column wire the problem probably lies on another switch in the same row or column that has a faulty diode. Start by removing the coin door connector as that easily removes a bunch of possibly troublesome switches.

Mike V

#4 5 days ago

First thing to do, if you havn't already, is to obtain the manual and schematics. Armed with the manual you can identify and examine switch 2, which is the upper left target.
Next I would narrow the problem down to a wiring problem by putting the game into switch test and disconnecting J2 and J3 from the MPU. If the stuck switch error clears the problem is in the wiring and your looking for a short. If the error does not clear you have a board or power problem.

The freeze issue sounds unusual as it's typically an old MPU problem. Alteks seem to be very reliable, just for giggles, did you double check the game setting on the board and make sure it's configured for the right game?

I recommend start by trouble shooting the stuck switch error. Maybe there is a short and its messing with the PIA chips??
Also check the power test points on the MPU. If your 5v and 43v are bad the game would do weird things. If you get stuck and the filter caps on the SD board are original I would recommend replacing them and reflowing all the solder connections on the SD board.

Good luck. Let us know.

#5 4 days ago

First of all I want to thank everyone who replied here. I am fairly new to pinside and what a great group of people with willingness to help. BarakandI, I failed to remember that when troubleshooting any problem always look at the obvious first. Yes, the tilt plumb bob was off the hook and shorting out causing the game to freeze. I had the backglass off so I never saw the tilt light come on. My bad.......

On the switch error, I clipped the cap off and now the error is gone and the switch works fine. Should I replace that cap or just leave it off? The game seems to now play fine.

On a side note and off topic for this sub group, the playfield paint is in good general condition but the surface looks rough. I have not cleaned or waxed it yet. All the rubbers need replacing so I was going to strip everything off of it and maybe clear coat it. What are the thoughts and/or suggestions in regards to sealing and old playfield?

#6 3 days ago
Quoted from Pin_Bob:

First of all I want to thank everyone who replied here. I am fairly new to pinside and what a great group of people with willingness to help. BarakandI, I failed to remember that when troubleshooting any problem always look at the obvious first. Yes, the tilt plumb bob was off the hook and shorting out causing the game to freeze. I had the backglass off so I never saw the tilt light come on. My bad.......
On the switch error, I clipped the cap off and now the error is gone and the switch works fine. Should I replace that cap or just leave it off? The game seems to now play fine.

It will work without the cap but switch may not register/score fast quick hits. If you think it's playing fine without you can leave it off.

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