Apple-1 RAM Not Working

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Last seen: 2 months 3 weeks ago
Joined: Nov 3 2024 - 10:03
Posts: 15
Apple-1 RAM Not Working

When I try running a simple command on my Apple-1 replica, such as 4F.52 to list blocks of memory, it doesn't seem to be registering that address and always prints the address 0000 with random values. The values are either 88 or 80. Has anyone seeing anything like this before?

 

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Last seen: 4 hours 11 min ago
Joined: Apr 1 2020 - 16:46
Posts: 1031
The WOZmon needs properly working DRAM . . . always.

Oh, this symptom is typical for a bad DRAM, somewhere.

 

But your DRAM  almost  works as otherwise the WOZmon would likely crash (it uses subroutines, which need a properly working stack).

 

I recommend you to run my 'diagnostics page' which you somehow got from your PROM vendor. It will tell you which DRAM is bad.

 

- Uncle Bernie

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Last seen: 2 months 3 weeks ago
Joined: Nov 3 2024 - 10:03
Posts: 15
Good callout. The issue was

Good callout. The issue was that I had populated the W bank partially (I didn't have all of the chips yet) and did not add a jumper for the W bank. Removing the chips from the W bank or adding a jumper for W fixes the issue. My guess is that the W bank was conflicting with the X bank since it had data on it but it wasn't tied to anything.

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