I bought a Gottlieb Circus project machine. So far I have gotten the CPU working again with the help of Marco Alba's test chip - Shout-out - Great stuff!

However now, when you turn the game on, it waits 5 seconds and then you get the attract mode. But nothing else, no coin-up, no response from the test switch, or the tilts. The Displays show "000000" but never switch to a high score. ALSO- the credit display has nothing on it - Ever. So there you have it. I was hoping to at least get the sound board to play some notes of encouragement, but not knowing ANYTHING about Gottlieb - System 80 or otherwise - I'm at a loss for where to go from here. I've tested the voltages, and all seems well.

Can someone point me in the right direction? thanks!

-Brian

I don't THINK it's the slam switch - If it's a slam switch problem you get the "Wavy" zeros problem - Right? and the game never boots.

This game boots, and goes into attract mode.

However it doens't respond to any of the switches - Test, Tilt, Coin-up, etc. It DID respond when I flipped switch - 28? The switch that controls whether or not the game should display "Attract Mode" where the playfield lights light sequentially and such. hahah, I'm pretty sure everyone reading this knows what attract mode is!!

Marco on my original thread about the motherboard suggested that it might be one of the 74LS chips that have something to do with the switch matrix. Hell, with all the other chips I've had to replace on this motherboard (I was thinking of calling it a MF board) but yeah- I've replaced the 6502, all three 40 Pin Riots (what a riot that was), and then the 4069, and 4081 chips. That was just to get the board to this point. He gave me some pretty good suggestions on how to test the switch matrix to see if that's getting the "attention" it needs to. Heh.

Thanks everyone!

-Brian

EDIT- Yes, or, I mean no, it's not the Slam Tilt. I know that is the problem a lot of the time on these games, but I tried holding the slam tilt open and sure enough, I got the Wavy Zeros, and the game woudln't boot. Just wanted to clarify that.