I'm still working on this thing, it's not working any more. Instead of showing the pattern, the LEDs stay lit and won't turn off.
I checked the ROM, the right data's loaded. That was the problem I had before, but it's not that this time. I checked every power and chip enable pin, they're all connected correctly. I checked all the data and address lines, they're connected properly...

I did find a problem with the clock timer, the 74LS04. it wasn't producing a wave. I don't have the proper equipment to check, I test it by connecting a LED between the chip and the power, then turning it around to see if its producing both positive and negative. First time I tried, it was only producing a positive output. I replaced the chip with a spare and it seemed to work normally, as far as I could tell. it was producing positive and negative output. The computer wasn't working properly though.

That's about all I can think of at the moment. It's got me stumped, it was working last time I checked and now it's not. Can anyone provide any suggestions? Can you see something obvious that i've missed? Anything?

I remember always having problems making an oscillator work using an 'LS' inverter and a crystal. I had better luck using a CMOS 4069 inverter. But if I were you, I would just avoid that situation altogether and buy a can oscillator. They're much more dependable.

Someone here suggested that you can place a AM radio close to your circuit and listen for the activity of the code racing through its paces.

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

Okay... what's a can oscillator? Is that the type with 4 pins? and how would I use the radio? Do I have to tune it to the same frequency as the CPU?

Yes can oscillators have 4 pins, usually Power, Gnd, Output Enable, and Signal Out. Make sure you get one that's 5V power.

What size resistor do you have in series with your LED tester?

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

Are you getting a good reset pulse with a clean (debounced) release? Are IRQ\ and NMI\ pulled up? I see you have a VIA there. Make sure its CS1 and CS2\ are true before phase 2 rises, ie, that you didn't bring phase 2 into the select logic. (You probably did it right if it worked before.)

There might be something helpful on the debugging page of the 6502 primer, at http://wilsonminesco.com/6502primer/debug.html . There are a lot of tips at viewtopic.php?t=342

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

If he was using a LED without a resistor to test signals off the 6502, he may have 'eventually' overloaded the output drivers. This would be my first concern, especially since he had it working. I am unsure of his skill level.

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

When using a voltage source, always have a resistor. Think about what happens when the voltage changes by a small amount, with no resistor, the LED current would shoot up. If it is current source, then you would not need a series resistor because the LED would run at the current source level.

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pcb assembling