Hello all,

We've just finished 'semi-restoring' our TZ. Cleaning the playfield, applying a playfield protector, fixing plastics and all sorts of mod stuffs.

The problem is, that the previous problem is still there: the machine thinks that some balls are powerballs where they are not. Mind you, the problem is not with the proximity sensor in the ballthrough, that one works fine. It is the sensor under the playfield, attached to the subway between the gumball exit and the VUK. The problem is that some balls are missed, and the powerball start procedure begins, but all switches, including the prox. sensor on the subway are working. If I hold a metal ball close to the sensor, it registers. If I hold the powerball close to it, it does not.

In the end it results to a credit dot, with the description 'pinball missing in gumball machine'. It gets kind of annoying after 3 or 4 'powerballs' in one game.

Also, another thing I've observed is that our machine cannot be leveled further down. It plays kind of slow, not my way of playing. We have the backleg adjusters screwed all the way down, and even removed the front adjusters completely, but the machine is still not properly leveled, and the level indicator bubble is still almost all the way up. Could it be that we have the wrong legs, or that they are incorrectly installed?

*edit* As can be read in post #17 the problem was in one of the metal balls. It could not seem to activate the proximity switch well enough. The rest of the balls was fine, but a new set of pinballs will not hurt this machine.

Yes. I fixed the legs, thanks a bunch, I did not see much machines with 3 leg holes. That's one thing down. Any suggestions on the other issue?

Yup, I've tried exactly that. When I drop it from the gumball onward, I get gumball exit, slot proximity, then it lands in the slot kickout switch. Somewhere between there is also the mini-playfield switch in the sub. It goes very fast, but I think all switches trigger. I really don't know why half the time it misses the metal balls.

I'm not nearby at the moment, but let me tell you that it's right against the plastic. I've even thought of mounting it a little further from the plastic, to see if that makes sense, but I have not yet come to that.

Played a few balls just now, and it seemed fine. Metal ball got out of the gumball, through the subway, and out of the scoop. No powerballs. It also went fine with the ceramic ball. But somehow I'm not convinced yet. Lets see where time takes us. At least it proves that all sensors work, and I only need to find out why it sometimes doesn't. Maybe reflow the connectors of the slot prox is a good idea.

Well, I think I found the problem. Upon closer inspection of the slot proximity board, I found a tiny blob of solder, including a little strand of wire between one of the chip's legs. It was not soldered on it, it was merely making contact between two legs of the chip. It was wedged in there, and I could easily take it out with a screwdriver. What I think was happening is that it acted as a cold solder joint, and it could have made contact every now and then, especially as a ball rolled over the subway over the board. I think it is the cause of our intermittent problems, and why it acted up and left every once in a while.

Well, thought that was it, but no dough.

Played a game or two today, and got one "powerball" after another. Seriously how hard can it be? I'm kind of running out of options. I've thought about putting my phone on camera mode in the cabinet facing the slot prox. sensor, then run a couple of balls through the subway. See if the LED of that board lights up at all.

Everything works as it's supposed to, except for properly detecting the type of ball when it comes through the subway. That means it can "miss" when the ball exits from the gumball machine, but also when you hit the camera, and the ball comes back through the slot machine using the same subway. There are no display/screen problems.

I haven't had time to check, as I'd rather play pins than fix them.

Well I recorded from inside the machine in switch test a while ago. It shows that the prox. sensor is working fine. Basically, its always working fine in test mode, but as soon as a game is started, the fun begins, and it is a guessing game which normal ball becomes a special powerball.

All switches seem to be working in the switch test. Could starting a game change something?

Small breakthrough here, thought this was interesting for other people that might have the same problems. As it it is/was still unresolved for so long I figured I post an update.

I was just working on the TZ in question, and once again everything seemed to work. Held a metal ball up to the proximity sensor in the subway, registered. Powerball does not. With the playfield down, threw in some balls in the gumball exit, checked all switches as the ball activates them. Gumball exit -> the camera subway -> proximity switch -> slot machine kickout. All fine.

HOWEVER ... There was one metal ball that consistently did not activate the proximity switch. The rest of the balls seem okay, and do activate it. Did a quick check, and the balls are slightly magnetized. That's not surprizing as there are multiple magnets in this game, but I would never have throught it would cause problems in the proximity switch. It could very well be, as it is an inductive sensor. The whole principle of that sensor is inducing eddy currents in the metal ball that affect the sensor circuit, so it can measure.

I'll give it a couple of tries with that one ball removed. If it plays better, I think it's high time to replace the remaining 5 metal balls as well with brand new shiny ones.

*edit* Aaaand as a matter of fact the problems are gone. Who would've thought it was just one ball indistinguishable from the rest causing problems. Well I'm glad it's resolved.