(Topic ID: 206937)

Gottlieb System 3 - Gladiators - mpu troubleshooting

By TheWiz

6 years ago



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  • 8 posts
  • 3 Pinsiders participating
  • Latest reply 6 years ago by TheWiz
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#1 6 years ago

I have a Gottlieb System 3 machine that needs lots of work. Somehow the adjustment pot on the 5volt regulator was missing so the full 12 volts was applied to the 5v rail. Needless to say the board set does not boot. I am going through each board on the bench to get them working, starting with the mpu. What I am looking for is some in depth theory of operation for the mpu. I have read just about everything I can find on the web about these and nothing really explains how it all works, just some tips on common failures and chip swaps. The main issue is that all the chips except the game eprom and ram are soldered in (with every ic leg bent over I might add). I really don't want to have to unsolder and replace every chip if I don't have to.

I do have a Super Mario Bros. Mushroom World game that is working. I repaired this one months ago so I do have something to compare with. My first task is to get the mpu to run on the bench.

The battery was missing altogether on the board so I installed a battery holder and battery. I then found that the DS1210 was bad. I had 3.15 volts from the battery and 5 volts from the supply but it was still not passing 5 volts to the memory. I replaces the DS1210 and that now works. I am still not getting the LED to flash like it should if everything is running, which my good board from SMBMW does. I have replaced the 74HCT123AN which did not help. I also have a jumper on the disable reset line so I do not get constant reset on pin 40 of the cpu.

So, I am looking for some detailed information on the theory of operation on how the circuits is supposed to work. I have an electronics background and the all the tools needed to troubleshoot computers, which I have done for 40 years, so the more detailed the better.

Thanks in advance for any information anyone can provide. If there is nothing out there like what I am asking for I would be happy to provide any learning I might make if folks think it would be helpful.

#4 6 years ago
Quoted from MarAlb:

I did program a testrom for Gottlieb system 3 boards which makes troubleshooting a bit more easy. Send me a PM with your email address if you want to try it.
Marco

Thanks, I will do that once I get verified on Pinside so I can send a PM. I would like to try it out.

#5 6 years ago

I did some more work on the mpu board. After replacing a couple of chips that I thought my logic probe was telling were bad (the Dallas DS1210 was bad) I decided to do what I thought about doing in the beginning which was swap the game ROM with my Super Mario Bros. Mushroom World game ROM. When I did that the board boots and the LED flashes. My next step will be to verify with the logic probe the PIA inputs and outputs and some other signals. Once that is done I will put in it my SMBMW game and see if it functions correctly. If that works out it is on to the other boards.

Thanks to Marco for sending me the test ROM code. I will work on getting my burner setup tonight and making some chips for it. I will try them out later and let folks know how it goes.

Anyone know of the best place to get Gottlieb game ROMs? I don't think the code is available on the web is it?

#7 6 years ago

Thanks to Marco I got a game rom programmed and installed. The board boots on the bench, still has issues in the game so I will go from there.

2 weeks later
#8 6 years ago

After playing with the board with the testrom it appears that the extent of the damage was the Dallas1210 chip, the game rom and the 6264 memory chip. Have it booting up nicely with it configured for 6116 memory until I get some 6264 chips.

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