Quoted from Timmo:
Your missing wire goes down to pin 4 of the coin door connector on my machine, but ends there. It shows up in the cabinet schematic, but looks to be unused.
Thanks very much for that Timmo, I will now assume that wire was never part of my loom as I can't see it anywhere and assume this does not cause some weird matrix issue, but I will hook up a wire to pin 4 of the coin door to test, just in case.
Quoted from Joydivision:
Mine does it occasionally. It just starts up, goes for a few months it seems then stops. Has been normal for a while now.
As other people have experienced this too & you have replaced the boards it looks like it is just an anomaly with Centaur. Must admit I hate it when it starts up, it's really annoying & I would like to know if their is a fix for it too.
Joydivision, you may be correct that it is just a Centaur thing, in fact I hope you are because then I can give up looking for a fix. But I can't help wondering why more people didn't report that theirs does this and why one person said they stopped theirs from doing it? Perhaps theirs was intermittent and they didn't play enough for it to do it again?
It would be great if a few Centaur owners could do this test for me and see if theirs makes the sound. I find that if I take off the glass and start a game and repeatedly activate the top rollover and the left bumper at the same time it will make the sound. Sometimes it will take a couple of minutes to start doing it but then it will do it multiple times in a row. If the Queens chamber drop targets are down while doing this test it will do it much sooner. That is why I have been directing my attention to these areas and have replaced all the diodes on those switches. That is my way of forcing it to make the sound for troubleshooting testing, but it will make the sound sometimes during normal gameplay it just takes longer to test as I can often play 3 or 4 games before it does it.
Here is the link to the sound again, does it a couple of times at about 10secs and a couple at the end 22secs.
Now that I know it still does it with new boards and new connectors I have been wondering if it is something to do with EMI through the wires as others have reported for ghost pop bumper activations. Mine had ghost pops also which I have stopped almost completely by running new power wires to the pop bumpers.
It seems the sound happens when the soundboard is overloaded by too many sounds happening at once, so yeah it could be a code issue, but why are more people not reporting it as normal if that is the case?
I have another issue that has me wondering, when I use my original soundboard the speech callouts work normally. But when I put the new "myPinballs" S&T board in the speech call outs cut out when I press the flippers. I asked applejuice about this and he suggested looking at J4 on my MPU board, but I have put a new connector there and it does it with the original board and the new repro MPU board. I have run new wires from the flipper solenoids to the new Solenoid board and put new diodes on the flipper buttons and the flipper mechs and solenoids are new and I have tried to separate the wires from the loom and used ferrite core31 snap ons to reduce possible EMI so I am running out of options.
Perhaps if I can get others to confirm that the weird sound above is a common thing with Centaur then I will just go back to using my old soundboard which doesn't cut out and forget trying to fix it and see if I can put up with knowing I can't fix it. (Would be a shame as the new soundboard sounds much better apart from cutting out speech)
Unfortunately at the moment this is sucking all the fun out the game for me and I'm not playing it just troubleshooting. In fact it's sucking the fun out of my games room altogether I am even considering giving up and selling it at a loss and buying a different game which would be a shame as Centaur was a grail pin for me and I looked for one for ages and I have put a heap of time and money into fixing it up.