MataHari issues

YellowDog

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Donor 2011, 2013
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My MataHari has just started showing some peculiar issues and I would like some advise where to start looking.

It runs fine for about an hour and then the displays start to flicker and it eventually locks up and doesn't do anything. The time does not seem to vary weather it is being played or just sitting idle.

I have rebuilt the +5V power supply (Big Daddy rebuild kit) and that didn't make any difference.

It has the original Bally power supply board but the CPU board was replaced with the Alltek Ultimate CPU board.

Any help would be appreciated.

ken
 
I'll state the obvious and say that something is heating up and causing a problem. You could turn the game off and do the old finger test to see what's hot but some stuff is just going to be hot anyway (like the resistors on the rectifier board. Those will be really hot). So that might not be the best solution. It's worth a try. Just don't burn yourself on anything.

First rule of pinball troubleshooting: check voltages.

I would check the voltages when the problem happens. Start at the rectifier board and check at the test points on the other boards. I've seen this kind of problem happen due to a bad solder joint on a bridge on the rectifier board. Could be something like that.

Have you replaced the filter cap for the +5V? Have you rebuilt the connectors at the rectifier board (does it need it?). What about the other connectors carrying power throughout the game? Any pins look burnt? If it's any of those things you should be able to see the voltage dropping out when the problem happens.

You could also consider disconnecting the displays when the problem is happening (with the game off) and run it without displays to see if the problem re-occurs. A bad display can cause the MPU to lock up.

There are some ideas. That kind of problem could be many things.
 
Thanks for the reply.

I tried checking the voltages (first rule ASAP - Always Start At Power). It was 4.95V cold and 4.94V when it was freaking out. Close enough that it could just be the meter. But since it was the original power supply board, it was worth rebuilding. After rebuilding the voltage was 4.97V.

I looked at all of the connectors and did not see any that looked like they were burning. No discoloration and no warped plastic.

I am not sure disconnecting the displays would help because by the time they are displaying random crap the playfield has stopped responding. I will try it the next time I see the displays flashing randomly. The high voltage section was the next thing I was going to rebuild.

ken
 
If you haven't re-pinned any of the connectors, I'd start looking there. Sometimes it's hard to tell if you have a cracked header joint or a pin inside the connector.
 
When it locks up, does turning it on and off fix the problem for another hour or so?

If you have to wait awhile for the boards to cool, how many flashes are you getting on the mpu?
 
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