I have Gottlieb Arean that plys 100% other than no sound and the dip swithes are not working after the switch matrix was shorted to solenoid voltage. I have a different thread with regards to the sound problem.

So this is what I have so far.

No dip switches are registering. As it says in the manual, when I go to test mode turn on all the even number and turn off the odd dip switches it displays 00 00 00 00 instead of AA AA AA AA. When I turn off the even numbers and turn on the odd numbers it again shows 00 00 00 00 00 instead of 55 55 55 55 55.

So obviously the microprocessor is not seeing any of the switches. I have already replaced U4, and z14. Other than DIP switches not working and no sound, the game plays 100%. The diodes associated with the switch banks test good. I have checked traces between z15 and the the diodes that are connected to the switch banks and they test good. I assume Z33 to be good since the rest of the game and lamps play correctly. Z13 tests good and z15 has both high inputs and outputs in attract mode. (suspicious of Z15 since it is connected to all the switches)

suggestions on what would keep the micro from seeing any of the switches?

(also if anyone wants to explain the function of z15 and z33 and how they interact with the rest of the switch matrix I would appreciate it.)

thanks

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Ed thanks for the reply very helpful.

I did not see the output pin 12 on Z12 go low when reading dip switches. (I am reading dips in test mode. Hitting the credit button to have them read and observing any changes on logic probe). I also did not see pin 16 on U5 go high at any time.

On zZ12 if I force pin 13 high with 5 volts I get nothing on pin 12 on the logic probe. No light or sound. The chip was already socketed so I substituted another and got the same thing. I don't understand that. What do you suggest?

I found that pin 6 of Z15 switch is not toggling hi/lo when I ground the output of z12. All other inputs and outputs of Z15 are acting normal. So I will place an order to get a replacement when GPE opens on Jan 2 and see where that takes us.

I still don't understand why when pin thirteen is forced high on z12 pin twelve does not go low. It is dead, no output at all. If anyone can explain this I would appreciate it.

I changed Z12 with another known working chip and I had the same reading. No output of pin 12 when pin 13 is forced high.

So I am left to suspect that something external is causing this.

However I don't understand how this happens. I understand how a short to ground will drag a pin low. I would assume a short to 5v would force a pin high...not cause no output at all. Could you explain further how this happens? Any obvious places to start checking?

Thank for the help

I have grounded Z12 before (with the chip in) and 2, 5, 9 and 12 of Z15 all went low. I had to do this when I was measuring the outputs of Z15 and this is where I found that output pin 6 of Z15 was not toggling high/low like the other outputs pin 3, pin 8, pin 11.

With regards to output pin 16 on U5...actually I said in earlier post that I have NEVER seen it go high (this must be my problem) thus pin 13 on z12 stays high and pin 12 doesn't go low and the dips never get read.

i will change u5 and see if this doesn't fix things.

with regards to your questions at the end.......When I pulled pin 13 high on z12 of course pin 12 should go low. But what I got was nothing when measuring with my logic probe. Meaning ...dead. No high or low light indicated, and no high or low sound. Nothing. I substituted a known good chip ( z12 is socketed) and got the same result. Nothing. This I don't understand. I tested multiple times and made sure I was on solid with the probe on the pin.

Could forcing a Z12 pin 13 high with a stuck low pin 16 at U5 somehow cause this?? I wouldn't think so but.....

thanks for the replys. it has really helped my understanding of the switch matrix and how the dip switches are read

The game would not boot afterwards and game sounds were played incorrectly then lost entirely.

I changed out u4, u6, z12, z14, z34. I now boots and plays 100%. Except no sound. The YRoms are very hot, and the board is not booting so I assume they have failed. The 6502s test good. The dips are not currently being read.....

This issue has been resolved and the game is now playing 100% including recognizing the dip switch settings. Z15 was the issue.

Prior to pulling any switches high or low I did start with observation. However I thought pin 16 at U5 was ALWAYS low using the logic probe. Upon checking again I could hear the slightest change in tone even though the light never left "low". This change in tone (but not light) was replicated at pin 13 of Z12 and same at pin 12 of Z12. Since I had misread the probe because the change was so fast, I was thrown off.

So now I really suspect Z15 since it is last in line to the dip switches. (The rest of game plays correctly so Z33 must be good...but I checked it anyway...it was)

Just to verify I tested Z15 by mometarily grounding the output of z12. I found that pin 6 of Z15 switch is not toggling hi/lo when this happens. All other inputs and outputs of Z15 tested normal.

Socketed and changed out Z15 and now all is better.

Thanks for the help Cactus Jack and GPE....