Friday, October 18, 2019
never ever adjust switches with power on
Finally after a few years I start to work on my pinball machines again. I moved 3 years ago, all my machines were put in the garage.
For a lot of reasons I didn't work on them..
It took me half a year to put them all on legs, but I didn't play almost any if them. I knew most of them were broken, and also needed a cleaning and new pinballs. The only machine I played often was one that I had bought after moving, as that was working and set up..
Now I have finally some time and motivation to start to setup the machines and fix them. Moving pinball machines is not good for them, most of them have some smaller or bigger issue..
Anyway, the game I set up today is Attack From Mars. I played it, it worked mostly correct. Only one coil sometimes works and sometimes doesn't.. I need to replace it, it probably is broken inside, but couldn't as all spare coils are somewhere in a box that I can't reach right now.
About a dozen lamps didn't work. Only one was actually a broken lightbulb, all the others just needed adjustment from the vibrations in moving.
I noticed one popbumper wasn't reacting like it should, a slow ball just rolled past it.
So I thought I would adjust the switch. With the power on, so I could immediately test how sensitive it was. Dumb dumb dumb..
Note that the interlock circuit is not connected on that game - opening the coin door does not cut the coil power. That's something else I need to look at later.
You probably guess what happened. I tell people for all those years now not to do this. Never work at the bottom of a playfield with power on. I thought I could, as I am experienced enough and was careful. And I was very careful, at least in the beginning. After a few minutes I was less careful and shorted something badly.
I am not even sure what I shorted exactly.. coil power to switch matrix or something else ? Only thing I know is I heard a crackling sound in the backbox (I would guess a bad capacitor) and something smelled burnt.
Now I have a game that doesn't boot up anymore. I haven't tested further but it looks like both the cpu (as it doesn't boot disconnected from the rest) and powerdriver board are damaged..
Next step is to check all voltages and test points, but I'm not motivated to do that right now...