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TZ Phantom Locks

  • Thread starter Thread starter ZeroTheHero
  • Start date Start date
Z

ZeroTheHero

Hi all,

In my quest to actually get to grips with those niggling problems in inaccessible areas...

My TZ has started giving me phantom locks. As far as I can see by looking without disassembling the whole thing, there are optos and then a kickout hole. There's something going on because I will (quite often) get a lock awarded without getting a ball in there, or (if lock is not lit) the kickout solenoid will fire - very irritating and somewhat confusing.

I have unscrewed the microswitch from the bottom of the pf. I know its not always possible to tell if it is working properly or not, but it *seems* OK.

So my question is... should I be looking to replace the microswitch as a first go, or is it likely to be one of the optos? It's another bloody difficult place to get to!

I have tried thumping the pf with the switch test on, and cannot get any of the switches (micro or opto) to fire - is that a clue?

Any ideas appreciated!

Thanks - Jon
 
Hello,

If it was my game I'd go into switch matrix test and check switch 88 (lock lower) which should need the weight of a ball to activate - make sure the metal is bent right and the micro switch isn't being a little bugger. Also check opto 84 (lock centre) and 85 (lock upper).
Maybe also check senoid 15 (lock release) is working ok.

Basically try to isolate the problem.

Paul.
 
If it is an opto, what would be the best way to test them?

Is it more likely to be the opto itself (i.e a replacement job) or a wire somewhere to the opto? Or is that impossible to say?
 
By using a digital camera that doesn't have an IR filter on it, point it at the emitter and poke wiggle the PCB/connector to see if it flickers.
 
When testing phantom switch closures, I tend to put the machine into switch test and leave it for an hour, then have a look an see what the last switch closure was.

Also if in doubt, replace the microswitch. The part is pretty cheap and is probably over 20 years old by now.

I know its not always possible to tell if it is working properly or not, but it *seems* OK.
Click to expand...
It's very, very easy to test whether a microswitch is working or not. Get a multimeter with continuity test, a couple of crocodile clips and test it properly with the machine off. Don't be tempted to use your fingers to trigger the switch, use a ball instead.

Could be flakey wiring, not just on the back of the opto but underneath the playfield as well. Usual rules apply, test the wire end to end (ie from the opto to where it plugs into the boards) with a multimeter. Also might be a flakey lm339 on one of the opto boards.
 
Thanks for the advice everyone. I'll see what I can come up with.

Sonny_Jim said:
It's very, very easy to test whether a microswitch is working or not. Get a multimeter with continuity test, a couple of crocodile clips and test it properly with the machine off. Don't be tempted to use your fingers to trigger the switch, use a ball instead.
Click to expand...

I don't think the point quoted above applies in this case though. It's not that the switch isn't working. I'd always test that with a ball - and indeed it certainly works OK when there actually IS a ball in there...

Sonny_Jim said:
When testing phantom switch closures, I tend to put the machine into switch test and leave it for an hour, then have a look an see what the last switch closure was.
Click to expand...

That seems like a very good idea - although I have a horrible feeling that its only happening during play. That will prove it one way or another though!

I'll report back!

Cheers all!
 
AH ha! So it looks like it's the central lock opto that's flaky. Put it into switch test and occasionally it will go on and off. So that's narrowed it down.

I'll investigate further....
 
Have you tried cleaning them with a cotton bud and some window cleaner?
 
Sonny_Jim said:
Have you tried cleaning them with a cotton bud and some window cleaner?
Click to expand...

That's going to be the second thing I try after making sure all the leads are securely plugged in first.

Not entirely sure how to get to them as yet (without dismantling half the machine!).
 
Sonny_Jim said:
Err, I would forget about the wires and just give em a good clean ;-)
Click to expand...

Cleaned it but no improvement. Checked the wires, but that didn't help either unfortunately. Soldering iron time!

Thanks for the help and ideas everyone, at least I now know which is faulty....
 
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