Recent content by mdeverhart

Can you post the code for the clock generator? I’m happy to look on GitHub too if you want to post the code there.

Instead of handling the tri-state in each module, try only handling it at the top level right before the chip IO. Each module will have a data_in, data_out, and oe port which you can use at the top level. If the part actually supports internal tri-states then this will be less efficient than...

Can you post a small code snippet somewhere? Is the tristate/bidir code constrained to the very edge of the design at the IOs?

Awesome! I might have stumbled on that earlier when I was looking at one of your other projects, but I’d forgotten it. Thanks!

If you’re seeing sharp pulses that line up with the edges of adjacent signals - yep, that’s the problem. It would be a great service to the community if you could write up what you’ve learned, maybe as an addendum to the Apple IWM document that clarifies, corrects, and adds more detail where...

It’s been recapped - the original solder would have been much cleaner than that. They also replaced the cap at C36 (top of your picture) with a tantalum instead of the original electrolytic can.

That’s actually how Apple’s service documentation recommended doing it, so that the dangling leg could be moved over and resoldered if the memory configuration ever needed to be changed back.

Thanks. I knew they were bad about that, but I hadn’t considered grabbing a copy for this purpose, and I hadn’t looked into the MAX7000 support. Time to grab it and throw it onto my NAS. From the Service Source it looks like it’s a socketed DIP right next to the socketed DIP ROMs.

Congrats! Verilog is definitely a good tool to have in the toolbox. Good to know! I haven’t done any CPLD designs for Classic Mac hacking, but I’d been considering taking that approach since it’s about the only 5V CPLD available in production anymore.

Out of curiosity, what SCSI IDs are you using for images on your ZuluSCSI? Just one image of ID=0, or are there other images present?

I doubt you’ve fried the LB. There’s a lot that needs to work right in order to get to the point where it shows the blinking question mark floppy, so that’s a really good sign. A few guesses: 1. The floppy probably has a short somewhere, likely introduced when you recapped it. A short on the...

That’s really cool, thanks for sharing!

How does the fan on the power supply seem? Are you running your tests with the lid on or off? I’m not sure which direction the air flows on the IIfx, but you may not be getting airflow over the RAM with the cover off, or with a bunch of other cards installed. You could try balancing a small fan...

What spot welder are you using? I have a number of batteries I want to recell or rebuild in new 3d printed cases, but I’m not sure which spot welder to get. It seems like it’s one of those product categories with infinite options of dubious quality…

Glad you figured it out, that’s great! I’d guess that someone enterprising could take measurements of the battery contacts on the LB and battery and design a 3D-printed alignment tool. I’m sure you can manually tweak it using the battery as a guide, as long as the battery has the same alignment...