Hello all,

I just recently bought my first two pinball machines. One of them is Xenon.

Yesterday, the machine began some erratic behavior with the sound. The background music just drops out occasionally. It seems to happen with an event such as a button/drop target activation, a pop-bumper getting hit, etc.

Then random stuff starts happening. It lights up the capture even though I've not yet gone through the sequence, and it will fake a "drain" periodically during play as if the game were over. It then allows me to launch a second pinball even though the other is still in play.

I just bought it and it is under a 30 day warranty. But man, I'd love to know if there is some simple stuff I can check. I've already opened up the backbox and checked connections and re-seated--they seem secure.

Anyway, if this is indicative of a certain part, I'd like to bring that part back instead of the whole machine.

I have a lot of experience with Arcade game repair and I'm not afraid to dig in--so any advice would be appreciated.

Thanks for the help, fellas. I'm going to check for that exit switch problem. At least right now--that seems a likely suspect.

Here is a video of the issue. (Happens a couple of times but most prominently at 1:50)

Doesn't seem to be directly related to the exit switch.

After fiddling with the game for an hour tightening up loose bayonet sockets and checking connections, it is playing solid now.

Since I didn't really find the problem I'm suspecting the caps are warmed up and working properly now and I might just as well go ahead and follow vid1900's Bulletproofing Power Board tips. Also in checking out the boards, I have noticed one other issue with some diodes. So here's what I've got planned so far:

1. The original battery seems to be in place still mounted to the PCB. I'm going to remove it and put a remote battery socket somewhere.

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2. There are three diodes on the Vocalizer board that appear to be getting a little hot. (CR1, CR2 and CR3) I'm not sure how much longer they'll last but the board looks like it's beginning to boil. Somehow I don't think just replacing the diodes will curb the inevitable so I'm going to look around here for ideas on what else could be causing all of that heat there. Of course, if you have an explanation you'd like to share here in the meantime--I'm all ears.

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3. The caps on the solenoid driver board seem to be original. I think I will replace those per the bulletproofing tutorial for sure.

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I had time this weekend to work on Xenon. As was suggested by vid1900, I "bulletproofed" the solenoid board:
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When working on it I noticed that R47 was just completely missing! I checked the manual and it showed that it was supposed to be there so I soldered in a spare 330K Ohm resistor I had laying around...

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I also replaced the three main caps on the sound board:
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I also fixed about half a dozen bad lamps and lamp connections too.

The background sound was still cutting out occasionally, so I read around and found that someone had a similar issue: When the machine had been running awhile, the background sound would stop and they would have to turn off the machine, then wait for it to cool, and then turn it back on to get the background sounds back. For him it turned out to be a bad 6821 PIA chip. I replaced that with no luck.

I noticed when working with the sound board that the pots were relatively unresponsive and "jumpy." That is to say the sound would cut out or come back depending on how much I turned a pot. I think I'll replace those next and maybe the 1uF caps too.

So it's still there but maybe I'm getting closer.

And now that I'm thinking about it, I think I'll replace the RAM on the sound board too. That crappy RAM goes bad all the time.

Almost there... Have the part, just waiting for down time to install. I will likely get to it on Wednesday and I'll update this thread again.

It isn't entirely surprising the machine has been running a bit more stable since implementing all of the other changes. None of the other anomalous behavior has returned--just the very occasional background sound cutting out. But with the static and cut-outs I get from the Sound board when messing with the pots I'm guessing that replacing the pots will fix up the problem nicely.

Stay tuned. Same bat-channel.

So I replaced the sound pots and that seemed to do the trick. I've not been able to replicate the problem since.

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After I replaced the sound pots I did some more work on the Sound board replacing:

-The crystal.
-A number of additional caps.
-The 1K RAM with a NOS part.

Thanks to all for your help and suggestions. Now I'm off to try and repair the lift tilt mechanism (the one with the ball) and get me a playfield support bracket. Apparently they are a unique size on Xenon!

Cheers!