Jeff, I think that might just be a photo artifact and not a drilled hole. Looks like maybe the backlight is bleeding? Doesn't mean that the LCD isn't the culprit, though! Maybe it's loose.
besser435, you're building a known-working design to run known-working code. That makes your troubleshooting easier, in a way. Either the problem is hardware failure - you've received some component that is defective (pretty unlikely, but not impossible) - or you made a mistake somewhere along the way (much more likely). It's hard to diagnose a mistake from a photo of a breadboard build that doesn't look much different from (actually, it looks nicer than many of) the literally hundreds of other photos of the same kit floating around on Reddit.
The experts who are telling you not to leave CMOS input pins floating and that you need more bypass capacitors are totally right; you should read those links and learn about parasitic capacitance. What's more, it's an easy fix. Adding a bypass cap and a ground return loop to each chip will probably take less than 5 minutes. It might even fix your problem! But I doubt it; Ben's kits usually work in spite of cutting some corners on best practices.
What kind of troubleshooting have you already done? Do you have a digital multimeter? I use this one:
https://www.amazon.com/ANENG-AN8008-Mul ... B076GZK62BIt is not too expensive, and is adequate for a hobbyist. It has a square-wave sense mode, so you can use it to check of your oscillator is working. (It won't tell you how clean your clock signal is, though.) What about the Arduino bus monitor; do you have that? Did you buy a commercial EEPROM programmer, or did you build one? (Or did the EEPROM come pre-programmed?)
I suspect that, since you don't have the clock module, that you've jumped straight into building the final kit, without building along with the videos, step-by-step. I think that might not be the best approach. I'm going to suggest you take a short break from your breadboard 6502 and build a clock module. Not necessarily the one in Ben's kit (read the Primer page on clocking the 6502 for more options) but a 555-timer circuit is an easy and cheap one to make. Take the trouble to really understand how it works! Engage with the circuit; try different resistor and capacitor values and see if you get the pulses you expect. Learn about the bistable and monostable modes of the 555-timer as well. If the output of your timer isn't symmetrical, do you know how to make it symmetrical? A plain 555-timer clock does drive the WDC 65C02, but it's technically not in spec (the rise/fall times are too slow). Do you know how to make them faster? The answer is in Ben's videos, but not always obvious, or delivered directly. (Hint: the secret to cleaning up your clock signal is disclosed in the PS/2 keyboard videos.)
Once you've armed yourself with better tools and better knowledge, you might just try rebuilding the whole kit, one step at a time, verifying as you go. If you take the "isolate and simplify" approach, when something does go wrong you'll have already eliminated many possible explanations. Of course, you should still re-check your previous steps. Just because your address bus was working last step doesn't mean that something hasn't come loose now! But if you know not just where each wire goes but *why* it goes there, what it's for, what it does when it's hooked up right, and what happens when it isn't, then each step will build your confidence and help focus your attention in the right direction when things don't work as expected.
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It looks as if a hole was drilled in it, which very possibly could have severed some of the traces. If so, that could explain the difficulties you're experiencing. It looks to me as if your project is 95% working... but something's gone awry in the very final stage, ie -- displaying the output.
